1
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Kay AM, Riley DB, Meredith P, Armin A, Sandberg OJ. A New Framework for Understanding Recombination-Limited Charge Extraction in Disordered Semiconductors. J Phys Chem Lett 2024; 15:4416-4421. [PMID: 38626394 PMCID: PMC11057038 DOI: 10.1021/acs.jpclett.4c00218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/05/2024] [Accepted: 04/10/2024] [Indexed: 04/18/2024]
Abstract
Recombination of free charges is a key loss mechanism limiting the performance of organic semiconductor-based photovoltaics such as solar cells and photodetectors. The carrier density-dependence of the rate of recombination and the associated rate coefficients are often estimated using transient charge extraction (CE) experiments. These experiments, however, often neglect the effect of recombination during the transient extraction process. In this work, the validity of the CE experiment for low-mobility devices, such as organic semiconductor-based photovoltaics, is investigated using transient drift-diffusion simulations. We find that recombination leads to incomplete CE, resulting in carrier density-dependent recombination rate constants and overestimated recombination orders; an effect that depends on both the charge carrier mobilities and the resistance-capacitance time constant. To overcome this intrinsic limitation of the CE experiment, we present an analytical model that accounts for charge carrier recombination, validate it using numerical simulations, and employ it to correct the carrier density-dependence observed in experimentally determined bimolecular recombination rate constants.
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Affiliation(s)
- Austin M. Kay
- Sustainable
Advanced Materials (Sêr-SAM), Centre for Integrative Semiconductor
Materials (CISM), Department of Physics, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Drew B. Riley
- Sustainable
Advanced Materials (Sêr-SAM), Centre for Integrative Semiconductor
Materials (CISM), Department of Physics, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Paul Meredith
- Sustainable
Advanced Materials (Sêr-SAM), Centre for Integrative Semiconductor
Materials (CISM), Department of Physics, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Sêr-SAM), Centre for Integrative Semiconductor
Materials (CISM), Department of Physics, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Oskar J. Sandberg
- Physics,
Faculty of Science and Engineering, Åbo
Akademi University, 20500 Turku, Finland
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2
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Oh J, Kim JH, Kim YR, Armin A, Lee S, Park K, Kang H, Lee K. Photopically Transparent Organic Solar Cells with Tungsten Oxide-Based Multilayer Electrodes. ACS Appl Mater Interfaces 2023; 15:42802-42810. [PMID: 37652403 DOI: 10.1021/acsami.3c08028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The tailoring of the average photopic transmittance (APT) of transparent organic solar cells (T-OSCs) has been the greatest challenge in building-integrated photovoltaic applications for future smart solar windows to regulate indoor brightness, maintain a human circadian rhythm, and positively impact human emotions by allowing the observation of the external environment. However, a notorious trade-off exists between the APT and power conversion efficiency (PCE) of T-OSCs, mainly due to the absence of highly conductive and transparent top electrodes, which are a key building block determining the PCE and APT. Herein, we demonstrate a new tungsten oxide (WO3)-based multilayer as a highly conductive and transparent top electrode that provides an excellent APT while maintaining a high PCE in T-OSCs. With the assistance of optical simulation based on a transfer matrix method to calculate the optimum thicknesses of the multilayer electrodes, we achieve the best-performing T-OSC with a PCE of 7.0% and a full device APT of 46.7%, resulting in a high light utilization efficiency of 3.27%, which is superior to that of T-OSCs based on the same photoactive system. Furthermore, superior thermal stability at 85 °C in an N2 atmosphere is observed in WO3-based T-OSCs, maintaining 98% of the initial PCE after about 231 h. Our findings provide new insights into the development of T-OSCs with high efficiency and transparency.
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Affiliation(s)
- Juhui Oh
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Ju-Hyeon Kim
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Yong Ryun Kim
- Department of Physics, Swansea University, Singleton Campus, Swansea SA2 8PP ,U.K
- Department of Engineering, University of Cambridge, Cambridge CB3 0FA, U.K
| | - Ardalan Armin
- Department of Physics, Swansea University, Singleton Campus, Swansea SA2 8PP ,U.K
| | - Sanseong Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Kiyoung Park
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Hongkyu Kang
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Kwanghee Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
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3
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Zarrabi N, Sandberg OJ, Meredith P, Armin A. Subgap Absorption in Organic Semiconductors. J Phys Chem Lett 2023; 14:3174-3185. [PMID: 36961944 PMCID: PMC10084470 DOI: 10.1021/acs.jpclett.3c00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Organic semiconductors have found a broad range of application in areas such as light emission, photovoltaics, and optoelectronics. The active components in such devices are based on molecular and polymeric organic semiconductors, where the density of states is generally determined by the disordered nature of the molecular solid rather than energy bands. Inevitably, there exist states within the energy gap which may include tail states, deep traps caused by unavoidable impurities and defects, as well as intermolecular states due to (radiative) charge transfer states. In this Perspective, we first summarize methods to determine the absorption features due to the subgap states. We then explain how subgap states can be parametrized based upon the subgap spectral line shapes. We finally describe the role of subgap states in the performance metrics of organic semiconductor devices from a thermodynamic viewpoint.
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Affiliation(s)
- Nasim Zarrabi
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Paul Meredith
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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4
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Kim JH, Kim YR, Kim J, Oh CM, Hwang IW, Kim J, Zeiske S, Ki T, Kwon S, Kim H, Armin A, Suh H, Lee K. Efficient and Stable Perovskite Solar Cells with a High Open-Circuit Voltage Over 1.2 V Achieved by a Dual-Side Passivation Layer. Adv Mater 2023; 35:e2300754. [PMID: 37021414 DOI: 10.1002/adma.202300754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
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5
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Shi F, Guo P, Qiao X, Yao G, Zhang T, Lu Q, Wang Q, Wang X, Rikhsibaev J, Wang E, Zhang C, Kwon YW, Woo HY, Wu H, Hou J, Ma D, Armin A, Ma Y, Xia Y. A Nitroxide Radical Conjugated Polymer as an Additive to Reduce Nonradiative Energy Loss in Organic Solar Cells. Adv Mater 2023:e2212084. [PMID: 36924360 DOI: 10.1002/adma.202212084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/23/2023] [Indexed: 05/17/2023]
Abstract
Nonfullerene-acceptor-based organic solar cells (NFA-OSCs) are now set off to the 20% power conversion efficiency milestone. To achieve this, minimizing all loss channels, including nonradiative photovoltage losses, seems a necessity. Nonradiative recombination, to a great extent, is known to be an inherent material property due to vibrationally induced decay of charge-transfer (CT) states or their back electron transfer to the triplet excitons. Herein, it is shown that the use of a new conjugated nitroxide radical polymer with 2,2,6,6-tetramethyl piperidine-1-oxyl side groups (GDTA) as an additive results in an improvement of the photovoltaic performance of NFA-OSCs based on different active layer materials. Upon the addition of GDTA, the open-circuit voltage (VOC ), fill factor (FF), and short-circuit current density (JSC ) improve simultaneously. This approach is applied to several material systems including state-of-the-art donor/acceptor pairs showing improvement from 15.8% to 17.6% (in the case of PM6:Y6) and from 17.5% to 18.3% (for PM6:BTP-eC9). Then, the possible reasons behind the observed improvements are discussed. The results point toward the suppression of the CT state to triplet excitons loss channel. This work presents a facile, promising, and generic approach to further improve the performance of NFA-OSCs.
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Affiliation(s)
- Furong Shi
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Pengzhi Guo
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
- National Green Coating Equipment and Technology Research Centre, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Xianfeng Qiao
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Guo Yao
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Qi Lu
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Qian Wang
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Xiaofeng Wang
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Jasurbek Rikhsibaev
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Ergang Wang
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Chunfeng Zhang
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Young-Wan Kwon
- Department of Chemistry, KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Hongbin Wu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Yuguang Ma
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Yangjun Xia
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
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6
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Riley DB, Sandberg OJ, Zarrabi N, Kim YR, Meredith P, Armin A. Efficient Nanoscale Exciton Transport in Non-Fullerene Organic Solar Cells Enables Reduced Bimolecular Recombination of Free Charges. Adv Mater 2023:e2211174. [PMID: 36922698 DOI: 10.1002/adma.202211174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/05/2023] [Indexed: 05/03/2023]
Abstract
The highest-efficiency organic photovoltaic (OPV)-based solar cells, made from blends of electron-donating and electron-accepting organic semiconductors, are often characterized by strongly reduced (non-Langevin) bimolecular recombination. Although the origins of the reduced recombination are debated, mechanisms related to the charge-transfer (CT) state and free-carrier encounter dynamics controlled by the size of donor and acceptor domains are proposed as underlying factors. Here, a novel photoluminescence-based probe is reported to accurately quantify the donor-acceptor domain size in OPV blends. Specifically, the domain size is measured in high-efficiency non-fullerene acceptor (NFA) systems and a comparative conventional fullerene system. It is found that the NFA-based blends form larger domains but that the expected reductions in bimolecular recombination attributed to the enhanced domain sizes are too small to account for the observed reduction factors. Further, it is shown that the reduction of bimolecular recombination is correlated to enhanced exciton dynamics within the NFA domains. This indicates that the processes responsible for efficient exciton transport also enable strongly non-Langevin recombination in high-efficiency NFA-based solar cells with low-energy offsets.
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Affiliation(s)
- Drew B Riley
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
| | - Nasim Zarrabi
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
| | - Yong Ryun Kim
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
| | - Paul Meredith
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
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7
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Turedi B, Lintangpradipto MN, Sandberg OJ, Yazmaciyan A, Matt GJ, Alsalloum AY, Almasabi K, Sakhatskyi K, Yakunin S, Zheng X, Naphade R, Nematulloev S, Yeddu V, Baran D, Armin A, Saidaminov MI, Kovalenko MV, Mohammed OF, Bakr OM. Single-Crystal Perovskite Solar Cells Exhibit Close to Half A Millimeter Electron-Diffusion Length. Adv Mater 2022; 34:e2202390. [PMID: 36069995 DOI: 10.1002/adma.202202390] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Single-crystal halide perovskites exhibit photogenerated-carriers of high mobility and long lifetime, making them excellent candidates for applications demanding thick semiconductors, such as ionizing radiation detectors, nuclear batteries, and concentrated photovoltaics. However, charge collection depreciates with increasing thickness; therefore, tens to hundreds of volts of external bias is required to extract charges from a thick perovskite layer, leading to a considerable amount of dark current and fast degradation of perovskite absorbers. However, extending the carrier-diffusion length can mitigate many of the anticipated issues preventing the practical utilization of perovskites in the abovementioned applications. Here, single-crystal perovskite solar cells that are up to 400 times thicker than state-of-the-art perovskite polycrystalline films are fabricated, yet retain high charge-collection efficiency in the absence of an external bias. Cells with thicknesses of 110, 214, and 290 µm display power conversion efficiencies (PCEs) of 20.0, 18.4, and 14.7%, respectively. The remarkable persistence of high PCEs, despite the increase in thickness, is a result of a long electron-diffusion length in those cells, which was estimated, from the thickness-dependent short-circuit current, to be ≈0.45 mm under 1 sun illumination. These results pave the way for adapting perovskite devices to optoelectronic applications in which a thick active layer is essential.
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Affiliation(s)
- Bekir Turedi
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Muhammad N Lintangpradipto
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Aren Yazmaciyan
- KAUST Solar Center (KSC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Gebhard J Matt
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Abdullah Y Alsalloum
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Khulud Almasabi
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Kostiantyn Sakhatskyi
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Sergii Yakunin
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Xiaopeng Zheng
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Rounak Naphade
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Saidkhodzha Nematulloev
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Vishal Yeddu
- Department of Chemistry and Department of Electrical & Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Derya Baran
- KAUST Solar Center (KSC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Makhsud I Saidaminov
- Department of Chemistry and Department of Electrical & Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Maksym V Kovalenko
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Omar F Mohammed
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Advanced Membranes and Porous Materials Center (AMPM), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Osman M Bakr
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
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8
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Kim JH, Kim YR, Kim J, Oh CM, Hwang IW, Kim J, Zeiske S, Ki T, Kwon S, Kim H, Armin A, Suh H, Lee K. Efficient and Stable Perovskite Solar Cells with a High Open-Circuit Voltage Over 1.2 V Achieved by a Dual-Side Passivation Layer. Adv Mater 2022; 34:e2205268. [PMID: 36030364 DOI: 10.1002/adma.202205268] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Suppressing nonradiative recombination at the interface between the organometal halide perovskite (PVK) and the charge-transport layer (CTL) is crucial for improving the efficiency and stability of PVK-based solar cells (PSCs). Here, a new bathocuproine (BCP)-based nonconjugated polyelectrolyte (poly-BCP) is synthesized and this is introduced as a "dual-side passivation layer" between the tin oxide (SnO2 ) CTL and the PVK absorber. Poly-BCP significantly suppresses both bulk and interfacial nonradiative recombination by passivating oxygen-vacancy defects from the SnO2 side and simultaneously scavenges ionic defects from the other (PVK) side. Therefore, PSCs with poly-BCP exhibits a high power conversion efficiency (PCE) of 24.4% and a high open-circuit voltage of 1.21 V with a reduced voltage loss (PVK bandgap of 1.56 eV). The non-encapsulated PSCs also show excellent long-term stability by retaining 93% of the initial PCE after 700 h under continuous 1-sun irradiation in nitrogen atmosphere conditions.
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Affiliation(s)
- Ju-Hyeon Kim
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Yong Ryun Kim
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Juae Kim
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University (PNU), Busan, 46241, Republic of Korea
| | - Chang-Mok Oh
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - In-Wook Hwang
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Jehan Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Stefan Zeiske
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Taeyoon Ki
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Sooncheol Kwon
- Department of Energy and Materials Engineering, Dongguk University, Seoul, 04620, Republic of Korea
| | - Heejoo Kim
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
- Graduate School of Energy Convergence, Institute of Integrated Technology, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Hongsuk Suh
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University (PNU), Busan, 46241, Republic of Korea
| | - Kwanghee Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
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9
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Liu Q, Zeiske S, Jiang X, Desta D, Mertens S, Gielen S, Shanivarasanthe R, Boyen HG, Armin A, Vandewal K. Electron-donating amine-interlayer induced n-type doping of polymer:nonfullerene blends for efficient narrowband near-infrared photo-detection. Nat Commun 2022; 13:5194. [PMID: 36057674 DOI: 10.1038/s41467-022-32845-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/21/2022] [Indexed: 11/09/2022] Open
Abstract
Inherently narrowband near-infrared organic photodetectors are highly desired for many applications, including biological imaging and surveillance. However, they suffer from a low photon-to-charge conversion efficiencies and utilize spectral narrowing techniques which strongly rely on the used material or on a nano-photonic device architecture. Here, we demonstrate a general and facile approach towards wavelength-selective near-infrared phtotodetection through intentionally n-doping 500-600 nm-thick nonfullerene blends. We show that an electron-donating amine-interlayer can induce n-doping, resulting in a localized electric field near the anode and selective collection of photo-generated carriers in this region. As only weakly absorbed photons reach this region, the devices have a narrowband response at wavelengths close to the absorption onset of the blends with a high spectral rejection ratio. These spectrally selective photodetectors exhibit zero-bias external quantum efficiencies of ~20-30% at wavelengths of 900-1100 nm, with a full-width-at-half-maximum of ≤50 nm, as well as detectivities of >1012 Jones.
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Affiliation(s)
- Quan Liu
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium. .,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium.
| | - Stefan Zeiske
- Department of Physics, Swansea University, Singleton Campus, Swansea, SA2 8PP, UK
| | - Xueshi Jiang
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Derese Desta
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Sigurd Mertens
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Sam Gielen
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Rachith Shanivarasanthe
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Hans-Gerd Boyen
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Ardalan Armin
- Department of Physics, Swansea University, Singleton Campus, Swansea, SA2 8PP, UK
| | - Koen Vandewal
- Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium. .,IMOMEC Division, IMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium.
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10
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Zeiske S, Sandberg OJ, Zarrabi N, Wolff CM, Raoufi M, Peña-Camargo F, Gutierrez-Partida E, Meredith P, Stolterfoht M, Armin A. Static Disorder in Lead Halide Perovskites. J Phys Chem Lett 2022; 13:7280-7285. [PMID: 35916775 PMCID: PMC9376950 DOI: 10.1021/acs.jpclett.2c01652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/26/2022] [Indexed: 05/27/2023]
Abstract
In crystalline and amorphous semiconductors, the temperature-dependent Urbach energy can be determined from the inverse slope of the logarithm of the absorption spectrum and reflects the static and dynamic energetic disorder. Using recent advances in the sensitivity of photocurrent spectroscopy methods, we elucidate the temperature-dependent Urbach energy in lead halide perovskites containing different numbers of cation components. We find Urbach energies at room temperature to be 13.0 ± 1.0, 13.2 ± 1.0, and 13.5 ± 1.0 meV for single, double, and triple cation perovskite. Static, temperature-independent contributions to the Urbach energy are found to be as low as 5.1 ± 0.5, 4.7 ± 0.3, and 3.3 ± 0.9 meV for the same systems. Our results suggest that, at a low temperature, the dominant static disorder in perovskites is derived from zero-point phonon energy rather than structural disorder. This is unusual for solution-processed semiconductors but broadens the potential application of perovskites further to quantum electronics and devices.
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Affiliation(s)
- Stefan Zeiske
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Nasim Zarrabi
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Christian M. Wolff
- EPFL
STI IEM PV-LAB, Rue de la Maladière 71b, CH-2002 Neuchâtel 2, Switzerland
| | - Meysam Raoufi
- Soft
Matter Physics Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Francisco Peña-Camargo
- Soft
Matter Physics Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Emilio Gutierrez-Partida
- Soft
Matter Physics Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Paul Meredith
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Martin Stolterfoht
- Soft
Matter Physics Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Ardalan Armin
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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11
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Riley DB, Meredith P, Armin A, Sandberg OJ. Role of Exciton Diffusion and Lifetime in Organic Solar Cells with a Low Energy Offset. J Phys Chem Lett 2022; 13:4402-4409. [PMID: 35549280 PMCID: PMC9150110 DOI: 10.1021/acs.jpclett.2c00791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Despite general agreement that the generation of free charges in organic solar cells is driven by an energetic offset, power conversion efficiencies have been improved using low-offset blends. In this work, we explore the interconnected roles that exciton diffusion and lifetime play in the charge generation process under various energetic offsets. A detailed balance approach is used to develop an analytic framework for exciton dissociation and free-charge generation accounting for exciton diffusion to and dissociation at the donor-acceptor interface. For low-offset systems, we find the exciton lifetime to be a pivotal component in the charge generation process, as it influences both the exciton and CT state dissociation. These findings suggest that any novel low-offset material combination must have long diffusion lengths with long exciton lifetimes to achieve optimum charge generation yields.
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12
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Zeiske S, Sandberg OJ, Kurpiers J, Shoaee S, Meredith P, Armin A. Probing Charge Generation Efficiency in Thin-Film Solar Cells by Integral-Mode Transient Charge Extraction. ACS Photonics 2022; 9:1188-1195. [PMID: 35571262 PMCID: PMC9097587 DOI: 10.1021/acsphotonics.1c01532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Indexed: 06/15/2023]
Abstract
The photogeneration of free charges in light-harvesting devices is a multistep process, which can be challenging to probe due to the complexity of contributing energetic states and the competitive character of different driving mechanisms. In this contribution, we advance a technique, integral-mode transient charge extraction (ITCE), to probe these processes in thin-film solar cells. ITCE combines capacitance measurements with the integral-mode time-of-flight method in the low intensity regime of sandwich-type thin-film devices and allows for the sensitive determination of photogenerated charge-carrier densities. We verify the theoretical framework of our method by drift-diffusion simulations and demonstrate the applicability of ITCE to organic and perovskite semiconductor-based thin-film solar cells. Furthermore, we examine the field dependence of charge generation efficiency and find our ITCE results to be in excellent agreement with those obtained via time-delayed collection field measurements conducted on the same devices.
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Affiliation(s)
- Stefan Zeiske
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Jona Kurpiers
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Safa Shoaee
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Paul Meredith
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
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13
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Alqahtani O, Hosseini SM, Ferron T, Murcia V, McAfee T, Vixie K, Huang F, Armin A, Shoaee S, Collins BA. Evidence That Sharp Interfaces Suppress Recombination in Thick Organic Solar Cells. ACS Appl Mater Interfaces 2021; 13:56394-56403. [PMID: 34787408 DOI: 10.1021/acsami.1c15570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Commercialization and scale-up of organic solar cells (OSCs) using industrial solution printing require maintaining maximum performance at active-layer thicknesses >400 nm─a characteristic still not generally achieved in non-fullerene acceptor OSCs. NT812/PC71BM is a rare system, whose performance increases up to these thicknesses due to highly suppressed charge recombination relative to the classic Langevin model. The suppression in this system, however, uniquely depends on device processing, pointing toward the role of nanomorphology. We investigate the morphological origins of this suppressed recombination by combining results from a suite of X-ray techniques. We are surprised to find that while all investigated devices are composed of pure, similarly aggregated nanodomains, Langevin reduction factors can still be tuned from ∼2 to >1000. This indicates that pure aggregated phases are insufficient for non-Langevin (reduced) recombination. Instead, we find that large well-ordered conduits and, in particular, sharp interfaces between domains appear to help to keep opposite charges separated and percolation pathways clear for enhanced charge collection in thick active layers. To our knowledge, this is the first quantitative study to isolate the donor/acceptor interfacial width correlated with non-Langevin charge recombination. This new structure-property relationship will be key to successful commercialization of printed OSCs at scale.
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Affiliation(s)
- Obaid Alqahtani
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
- Department of Physics, Prince Sattam Bin Abdulaziz University, Alkharj 11942, KSA
| | - Seyed Mehrdad Hosseini
- Optoelectronics of Organic Semiconductors Institute, University of Potsdam, Potsdam-Golm 14476, Germany
| | - Thomas Ferron
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
| | - Victor Murcia
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
| | - Terry McAfee
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin Vixie
- Department of Mathematics, Washington State University, Pullman, Washington 99164, United States
| | - Fei Huang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China
| | - Ardalan Armin
- Department of Physics, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, U.K
| | - Safa Shoaee
- Optoelectronics of Organic Semiconductors Institute, University of Potsdam, Potsdam-Golm 14476, Germany
| | - Brian A Collins
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
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14
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Wang P, Li W, Sandberg OJ, Guo C, Sun R, Wang H, Li D, Zhang H, Cheng S, Liu D, Min J, Armin A, Wang T. Tuning of the Interconnecting Layer for Monolithic Perovskite/Organic Tandem Solar Cells with Record Efficiency Exceeding 21. Nano Lett 2021; 21:7845-7854. [PMID: 34505789 DOI: 10.1021/acs.nanolett.1c02897] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The photovoltaic performance of inorganic perovskite solar cells (PSCs) still lags behind the organic-inorganic hybrid PSCs due to limited light absorption of wide bandgap CsPbI3-xBrx under solar illumination. Constructing tandem devices with organic solar cells can effectively extend light absorption toward the long-wavelength region and reduce radiative photovoltage loss. Herein, we utilize wide-bandgap CsPbI2Br semiconductor and narrow-bandgap PM6:Y6-BO blend to fabricate perovskite/organic tandem solar cells with an efficiency of 21.1% and a very small tandem open-circuit voltage loss of 0.06 V. We demonstrate that the hole transport material of the interconnecting layers plays a critical role in determining efficiency, with polyTPD being superior to PBDB-T-Si and D18 due to its low parasitic absorption, sufficient hole mobility and quasi-Ohmic contact to suppress charge accumulation and voltage loss within the tandem device. These perovskite/organic tandem devices also display superior storage, thermal and ultraviolet stabilities.
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Affiliation(s)
- Pang Wang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Wei Li
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, U.K
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, U.K
| | - Chuanhang Guo
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Rui Sun
- The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Hui Wang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Donghui Li
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Huijun Zhang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Shili Cheng
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Dan Liu
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
| | - Jie Min
- The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, U.K
| | - Tao Wang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China
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15
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Kaiser C, Sandberg OJ, Zarrabi N, Li W, Meredith P, Armin A. A universal Urbach rule for disordered organic semiconductors. Nat Commun 2021; 12:3988. [PMID: 34183659 PMCID: PMC8238995 DOI: 10.1038/s41467-021-24202-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
In crystalline semiconductors, absorption onset sharpness is characterized by temperature-dependent Urbach energies. These energies quantify the static, structural disorder causing localized exponential-tail states, and dynamic disorder from electron-phonon scattering. Applicability of this exponential-tail model to disordered solids has been long debated. Nonetheless, exponential fittings are routinely applied to sub-gap absorption analysis of organic semiconductors. Herein, we elucidate the sub-gap spectral line-shapes of organic semiconductors and their blends by temperature-dependent quantum efficiency measurements. We find that sub-gap absorption due to singlet excitons is universally dominated by thermal broadening at low photon energies and the associated Urbach energy equals the thermal energy, regardless of static disorder. This is consistent with absorptions obtained from a convolution of Gaussian density of excitonic states weighted by Boltzmann-like thermally activated optical transitions. A simple model is presented that explains absorption line-shapes of disordered systems, and we also provide a strategy to determine the excitonic disorder energy. Our findings elaborate the meaning of the Urbach energy in molecular solids and relate the photo-physics to static disorder, crucial for optimizing organic solar cells for which we present a revisited radiative open-circuit voltage limit.
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Affiliation(s)
- Christina Kaiser
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
| | - Oskar J. Sandberg
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
| | - Nasim Zarrabi
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
| | - Wei Li
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
| | - Paul Meredith
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
| | - Ardalan Armin
- grid.4827.90000 0001 0658 8800Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, UK
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16
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Zeiske S, Sandberg OJ, Zarrabi N, Li W, Meredith P, Armin A. Direct observation of trap-assisted recombination in organic photovoltaic devices. Nat Commun 2021; 12:3603. [PMID: 34127670 PMCID: PMC8203604 DOI: 10.1038/s41467-021-23870-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 05/20/2021] [Indexed: 11/16/2022] Open
Abstract
Trap-assisted recombination caused by localised sub-gap states is one of the most important first-order loss mechanism limiting the power-conversion efficiency of all solar cells. The presence and relevance of trap-assisted recombination in organic photovoltaic devices is still a matter of some considerable ambiguity and debate, hindering the field as it seeks to deliver ever higher efficiencies and ultimately a viable new solar photovoltaic technology. In this work, we show that trap-assisted recombination loss of photocurrent is universally present under operational conditions in a wide variety of organic solar cell materials including the new non-fullerene electron acceptor systems currently breaking all efficiency records. The trap-assisted recombination is found to be induced by states lying 0.35-0.6 eV below the transport edge, acting as deep trap states at light intensities equivalent to 1 sun. Apart from limiting the photocurrent, we show that the associated trap-assisted recombination via these comparatively deep traps is also responsible for ideality factors between 1 and 2, shedding further light on another open and important question as to the fundamental working principles of organic solar cells. Our results also provide insights for avoiding trap-induced losses in related indoor photovoltaic and photodetector applications.
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Affiliation(s)
- Stefan Zeiske
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK.
| | - Nasim Zarrabi
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Wei Li
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Paul Meredith
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK.
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17
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Zarrabi N, Sandberg OJ, Kaiser C, Subbiah J, Jones DJ, Meredith P, Armin A. Experimental Evidence Relating Charge-Transfer-State Kinetics and Strongly Reduced Bimolecular Recombination in Organic Solar Cells. J Phys Chem Lett 2020; 11:10519-10525. [PMID: 33289568 DOI: 10.1021/acs.jpclett.0c02905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Significantly reduced bimolecular recombination relative to the Langevin recombination rate has been observed in a limited number of donor-acceptor organic semiconductor blends. The strongly reduced recombination has been previously attributed to a high probability for the interfacial charge-transfer (CT) states (formed upon charge encounter) to dissociate back to free charges. However, whether the reduced recombination is due to a suppressed CT-state decay rate or an improved dissociation rate has remained a matter of conjecture. Here we investigate a donor-acceptor material system that exhibits significantly reduced recombination upon solvent annealing. On the basis of detailed balance analysis and the accurate characterization of CT-state parameters, we provide experimental evidence that an increase in the dissociation rate of CT states upon solvent annealing is responsible for the reduced recombination. We attribute this to the presence of purer and more percolated domains in the solvent-annealed system, which may, therefore, have a stronger entropic driving force for CT dissociation.
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Affiliation(s)
- Nasim Zarrabi
- Sustainable Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Christina Kaiser
- Sustainable Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Jegadesan Subbiah
- Bio21 Institute and School of Chemistry, University of Melbourne, Parkville 3010, Australia
| | - David J Jones
- Bio21 Institute and School of Chemistry, University of Melbourne, Parkville 3010, Australia
| | - Paul Meredith
- Sustainable Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Ardalan Armin
- Sustainable Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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18
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Zarrabi N, Sandberg OJ, Zeiske S, Li W, Riley DB, Meredith P, Armin A. Charge-generating mid-gap trap states define the thermodynamic limit of organic photovoltaic devices. Nat Commun 2020; 11:5567. [PMID: 33149193 PMCID: PMC7642445 DOI: 10.1038/s41467-020-19434-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 10/13/2020] [Indexed: 11/19/2022] Open
Abstract
Detailed balance is a cornerstone of our understanding of artificial light-harvesting systems. For next generation organic solar cells, this involves intermolecular charge-transfer (CT) states whose energies set the maximum open circuit voltage VOC. We have directly observed sub-gap states significantly lower in energy than the CT states in the external quantum efficiency spectra of a significant number of organic semiconductor blends. Taking these states into account and using the principle of reciprocity between emission and absorption results in non-physical radiative limits for the VOC. We propose and provide compelling evidence for these states being non-equilibrium mid-gap traps which contribute to photocurrent by a non-linear process of optical release, upconverting them to the CT state. This motivates the implementation of a two-diode model which is often used in emissive inorganic semiconductors. The model accurately describes the dark current, VOC and the long-debated ideality factor in organic solar cells. Additionally, the charge-generating mid-gap traps have important consequences for our current understanding of both solar cells and photodiodes - in the latter case defining a detectivity limit several orders of magnitude lower than previously thought.
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Affiliation(s)
- Nasim Zarrabi
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom
| | - Oskar J Sandberg
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom.
| | - Stefan Zeiske
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom
| | - Wei Li
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom
| | - Drew B Riley
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom
| | - Paul Meredith
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom
| | - Ardalan Armin
- Sustainable Advanced Materials Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, United Kingdom.
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19
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Gielen S, Kaiser C, Verstraeten F, Kublitski J, Benduhn J, Spoltore D, Verstappen P, Maes W, Meredith P, Armin A, Vandewal K. Intrinsic Detectivity Limits of Organic Near-Infrared Photodetectors. Adv Mater 2020; 32:e2003818. [PMID: 33078513 DOI: 10.1002/adma.202003818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/18/2020] [Indexed: 05/15/2023]
Abstract
Organic photodetectors (OPDs) with a performance comparable to that of conventional inorganic ones have recently been demonstrated for the visible regime. However, near-infrared photodetection has proven to be challenging and, to date, the true potential of organic semiconductors in this spectral range (800-2500 nm) remains largely unexplored. In this work, it is shown that the main factor limiting the specific detectivity (D*) is non-radiative recombination, which is also known to be the main contributor to open-circuit voltage losses. The relation between open-circuit voltage, dark current, and noise current is demonstrated using four bulk-heterojunction devices based on narrow-gap donor polymers. Their maximum achievable D* is calculated alongside a large set of devices to demonstrate an intrinsic upper limit of D* as a function of the optical gap. It is concluded that OPDs have the potential to be a useful technology up to 2000 nm, given that high external quantum efficiencies can be maintained at these low photon energies.
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Affiliation(s)
- Sam Gielen
- UHasselt - Hasselt University, Institute for Materials Research (IMO), Agoralaan 1 - Building D, Diepenbeek, 3590, Belgium
- IMEC, Associated Lab IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
| | - Christina Kaiser
- Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Frederik Verstraeten
- UHasselt - Hasselt University, Institute for Materials Research (IMO), Agoralaan 1 - Building D, Diepenbeek, 3590, Belgium
- IMEC, Associated Lab IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
| | - Jonas Kublitski
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Johannes Benduhn
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Donato Spoltore
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Pieter Verstappen
- UHasselt - Hasselt University, Institute for Materials Research (IMO), Agoralaan 1 - Building D, Diepenbeek, 3590, Belgium
- IMEC, Associated Lab IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
| | - Wouter Maes
- UHasselt - Hasselt University, Institute for Materials Research (IMO), Agoralaan 1 - Building D, Diepenbeek, 3590, Belgium
- IMEC, Associated Lab IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
| | - Paul Meredith
- Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Ardalan Armin
- Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Koen Vandewal
- UHasselt - Hasselt University, Institute for Materials Research (IMO), Agoralaan 1 - Building D, Diepenbeek, 3590, Belgium
- IMEC, Associated Lab IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
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20
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Sandberg OJ, Zeiske S, Zarrabi N, Meredith P, Armin A. Charge Carrier Transport and Generation via Trap-Mediated Optical Release in Organic Semiconductor Devices. Phys Rev Lett 2020; 124:128001. [PMID: 32281832 DOI: 10.1103/physrevlett.124.128001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/13/2020] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
The impact of intermixed donor-acceptor domains in organic bulk heterojunction (BHJ) solar cells, using low-donor-content devices as model systems, is clarified. At low donor contents, the devices are found to exhibit anomalously high open-circuit voltages independent of the donor-acceptor energetics. These observations can be consistently explained by a theoretical model based on optical release of trapped holes, assuming the donors behave as trap sites in the gap of the acceptor. Our findings provide guidelines for reducing the large open-circuit voltage losses in organic solar cells and avoiding morphology-induced losses in state-of-the-art BHJ solar cells and photodetectors.
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Affiliation(s)
- Oskar J Sandberg
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
| | - Stefan Zeiske
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
| | - Nasim Zarrabi
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
| | - Paul Meredith
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
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21
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Schwarz KN, Geraghty PB, Mitchell VD, Khan SUZ, Sandberg OJ, Zarrabi N, Kudisch B, Subbiah J, Smith TA, Rand BP, Armin A, Scholes GD, Jones DJ, Ghiggino KP. Reduced Recombination and Capacitor-like Charge Buildup in an Organic Heterojunction. J Am Chem Soc 2020; 142:2562-2571. [PMID: 31922408 DOI: 10.1021/jacs.9b12526] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Organic photovoltaic (OPV) efficiencies continue to rise, raising their prospects for solar energy conversion. However, researchers have long considered how to suppress the loss of free carriers by recombination-poor diffusion and significant Coulombic attraction can cause electrons and holes to encounter each other at interfaces close to where they were photogenerated. Using femtosecond transient spectroscopies, we report the nanosecond grow-in of a large transient Stark effect, caused by nanoscale electric fields of ∼487 kV/cm between photogenerated free carriers in the device active layer. We find that particular morphologies of the active layer lead to an energetic cascade for charge carriers, suppressing pathways to recombination, which is ∼2000 times less than predicted by Langevin theory. This in turn leads to the buildup of electric charge in donor and acceptor domains-away from the interface-resistant to bimolecular recombination. Interestingly, this signal is only experimentally obvious in thick films due to the different scaling of electroabsorption and photoinduced absorption signals in transient absorption spectroscopy. Rather than inhibiting device performance, we show that devices up to 600 nm thick maintain efficiencies of >8% because domains can afford much higher carrier densities. These observations suggest that with particular nanoscale morphologies the bulk heterojunction can go beyond its established role in charge photogeneration and can act as a capacitor, where adjacent free charges are held away from the interface and can be protected from bimolecular recombination.
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Affiliation(s)
| | | | | | | | - Oskar J Sandberg
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | - Nasim Zarrabi
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | | | | | | | | | - Ardalan Armin
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
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22
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Hood S, Zarrabi N, Meredith P, Kassal I, Armin A. Measuring Energetic Disorder in Organic Semiconductors Using the Photogenerated Charge-Separation Efficiency. J Phys Chem Lett 2019; 10:3863-3870. [PMID: 31246471 DOI: 10.1021/acs.jpclett.9b01304] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quantifying energetic disorder in organic semiconductors continues to attract attention because of its significant impact on the transport physics of these technologically important materials. Here, we show that the energetic disorder of organic semiconductors can be determined from the relationship between the internal quantum efficiency of charge generation and the frequency of the incident light. Our results for a number of materials suggest that energetic disorder in organic semiconductors could be greater than previously reported, and we advance ideas as to why this may be the case.
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Affiliation(s)
- Samantha Hood
- Centre for Engineered Quantum Systems and School of Mathematics and Physics , The University of Queensland , Brisbane , QLD 4072 , Australia
| | - Nasim Zarrabi
- Department of Physics , Swansea University , Singleton Park , Swansea SA2 8PP , Wales , United Kingdom
| | - Paul Meredith
- Department of Physics , Swansea University , Singleton Park , Swansea SA2 8PP , Wales , United Kingdom
| | - Ivan Kassal
- School of Chemistry and University of Sydney Nano Institute , University of Sydney , Sydney , NSW 2006 , Australia
| | - Ardalan Armin
- Department of Physics , Swansea University , Singleton Park , Swansea SA2 8PP , Wales , United Kingdom
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23
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Abstract
Ultrasound sensors have wide applications across science and technology. However, improved sensitivity is required for both miniaturisation and increased spatial resolution. Here, we introduce cavity optomechanical ultrasound sensing, where dual optical and mechanical resonances enhance the ultrasound signal. We achieve noise equivalent pressures of 8-300 μPa Hz-1/2 at kilohertz to megahertz frequencies in a microscale silicon-chip-based sensor with >120 dB dynamic range. The sensitivity far exceeds similar sensors that use an optical resonance alone and, normalised to the sensing area, surpasses previous air-coupled ultrasound sensors by several orders of magnitude. The noise floor is dominated by collisions from molecules in the gas within which the acoustic wave propagates. This approach to acoustic sensing could find applications ranging from biomedical diagnostics, to autonomous navigation, trace gas sensing, and scientific exploration of the metabolism-induced-vibrations of single cells.
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Affiliation(s)
- Sahar Basiri-Esfahani
- ARC Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Ardalan Armin
- ARC Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK
| | - Stefan Forstner
- ARC Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Warwick P Bowen
- ARC Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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24
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Abstract
The dynamics of exciton quenching are critical to the operational performance of organic optoelectronic devices, but their measurement and elucidation remain ongoing challenges. Here, we present a method for quantifying small photoluminescence quenching efficiencies of organic semiconductors under steady-state conditions. Exciton quenching efficiencies of three different organic semiconductors, PC70BM, P3HT, and PCDTBT, are measured at different bulk quencher densities under continuous low-irradiance illumination. By implementing a steady-state bulk-quenching model, we determine exciton diffusion lengths for the studied materials. At low quencher densities we find that a secondary quenching mechanism is in effect, which is responsible for approximately 20% of the total quenched excitons. This quenching mechanism is observed in all three studied materials and exhibits quenching volumes on the order of several thousand cubic nanometers. The exact origin of this quenching process is not clear, but it may be indicative of delocalized excitons being quenched prior to thermalization.
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Affiliation(s)
- Nasim Zarrabi
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | - Aren Yazmaciyan
- School of Mathematics and Physics , The University of Queensland , St. Lucia , QLD 4072 , Australia
| | - Paul Meredith
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | - Ivan Kassal
- School of Chemistry and the University of Sydney Nano Institute , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Ardalan Armin
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
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25
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26
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Zhang S, Stolterfoht M, Armin A, Lin Q, Zu F, Sobus J, Jin H, Koch N, Meredith P, Burn PL, Neher D. Interface Engineering of Solution-Processed Hybrid Organohalide Perovskite Solar Cells. ACS Appl Mater Interfaces 2018; 10:21681-21687. [PMID: 29856202 DOI: 10.1021/acsami.8b02503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Engineering the interface between the perovskite absorber and the charge-transporting layers has become an important method for improving the charge extraction and open-circuit voltage ( VOC) of hybrid perovskite solar cells. Conjugated polymers are particularly suited to form the hole-transporting layer, but their hydrophobicity renders it difficult to solution-process the perovskite absorber on top. Herein, oxygen plasma treatment is introduced as a simple means to change the surface energy and work function of hydrophobic polymer interlayers for use as p-contacts in perovskite solar cells. We find that upon oxygen plasma treatment, the hydrophobic surfaces of different prototypical p-type polymers became sufficiently hydrophilic to enable subsequent perovskite junction processing. In addition, the oxygen plasma treatment also increased the ionization potential of the polymer such that it became closer to the valance band energy of the perovskite. It was also found that the oxygen plasma treatment could increase the electrical conductivity of the p-type polymers, facilitating more efficient charge extraction. On the basis of this concept, inverted MAPbI3 perovskite devices with different oxygen plasma-treated polymers such as P3HT, P3OT, polyTPD, or PTAA were fabricated with power conversion efficiencies of up to 19%.
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Affiliation(s)
- Shanshan Zhang
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics , The University of Queensland , Brisbane 4072 , Australia
- Institute of Physics and Astronomy , University of Potsdam , Karl-Liebknecht-Str. 24-25 , D-14476 Potsdam-Golm , Germany
| | - Martin Stolterfoht
- Institute of Physics and Astronomy , University of Potsdam , Karl-Liebknecht-Str. 24-25 , D-14476 Potsdam-Golm , Germany
| | - Ardalan Armin
- Department of Physics , Swansea University , Singleton Park , Swansea SA2 8PP , Wales , United Kingdom
| | - Qianqian Lin
- Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China , Wuhan University , Wuhan 430072 , P. R. China
| | - Fengshuo Zu
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
| | - Jan Sobus
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics , The University of Queensland , Brisbane 4072 , Australia
| | - Hui Jin
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics , The University of Queensland , Brisbane 4072 , Australia
| | - Norbert Koch
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
| | - Paul Meredith
- Department of Physics , Swansea University , Singleton Park , Swansea SA2 8PP , Wales , United Kingdom
| | - Paul L Burn
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics , The University of Queensland , Brisbane 4072 , Australia
| | - Dieter Neher
- Institute of Physics and Astronomy , University of Potsdam , Karl-Liebknecht-Str. 24-25 , D-14476 Potsdam-Golm , Germany
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27
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Gendron D, Maasoumi F, Armin A, Pattison K, Burn PL, Meredith P, Namdas EB, Powell BJ. A thiocarbonyl-containing small molecule for optoelectronics. RSC Adv 2017. [DOI: 10.1039/c7ra00693d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report the synthesis, characterization, and device properties of a novel thiocarbonyl iso-DPP derivative, namely 1,3,4,6-tetraphenylpyrrolo[3,2-b]pyrrole-2,5(1H,4H)-dithione.
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Affiliation(s)
- David Gendron
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences
- The University of Queensland
- Australia
| | - Fatemeh Maasoumi
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences
- The University of Queensland
- Australia
| | - Ardalan Armin
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences
- The University of Queensland
- Australia
| | - Katherine Pattison
- Centre for Organic Photonics & Electronics
- School of Mathematics and Physics
- The University of Queensland
- Australia
| | - Paul L. Burn
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences
- The University of Queensland
- Australia
| | - Paul Meredith
- Centre for Organic Photonics & Electronics
- School of Mathematics and Physics
- The University of Queensland
- Australia
| | - Ebinazar B. Namdas
- Centre for Organic Photonics & Electronics
- School of Mathematics and Physics
- The University of Queensland
- Australia
| | - Benjamin J. Powell
- Centre for Organic Photonics & Electronics
- School of Mathematics and Physics
- The University of Queensland
- Australia
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28
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Stolterfoht M, Armin A, Philippa B, Neher D. The Role of Space Charge Effects on the Competition between Recombination and Extraction in Solar Cells with Low-Mobility Photoactive Layers. J Phys Chem Lett 2016; 7:4716-4721. [PMID: 27790908 DOI: 10.1021/acs.jpclett.6b02106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The competition between charge extraction and nongeminate recombination critically determines the current-voltage characteristics of organic solar cells (OSCs) and their fill factor. As a measure of this competition, several figures of merit (FOMs) have been put forward; however, the impact of space charge effects has been either neglected, or not specifically addressed. Here we revisit recently reported FOMs and discuss the role of space charge effects on the interplay between recombination and extraction. We find that space charge effects are the primary cause for the onset of recombination in so-called non-Langevin systems, which also depends on the slower carrier mobility and recombination coefficient. The conclusions are supported with numerical calculations and experimental results of 25 different donor/acceptor OSCs with different charge transport parameters, active layer thicknesses or composition ratios. The findings represent a conclusive understanding of bimolecular recombination for drift dominated photocurrents and allow one to minimize these losses for given device parameters.
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Affiliation(s)
- Martin Stolterfoht
- Institute of Physics and Astronomy, University of Potsdam , Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany
- Centre for Organic Photonics & Electronics (COPE), School of Mathematics and Physics, The University of Queensland , Brisbane 4072, Australia
| | - Ardalan Armin
- Centre for Organic Photonics & Electronics (COPE), School of Mathematics and Physics, The University of Queensland , Brisbane 4072, Australia
| | - Bronson Philippa
- College of Science and Engineering, James Cook University , Cairns 4878, Australia
| | - Dieter Neher
- Institute of Physics and Astronomy, University of Potsdam , Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany
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29
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Stoltzfus DM, Donaghey JE, Armin A, Shaw PE, Burn PL, Meredith P. Charge Generation Pathways in Organic Solar Cells: Assessing the Contribution from the Electron Acceptor. Chem Rev 2016; 116:12920-12955. [DOI: 10.1021/acs.chemrev.6b00126] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dani M. Stoltzfus
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
| | - Jenny E. Donaghey
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
| | - Ardalan Armin
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
| | - Paul E. Shaw
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
| | - Paul L. Burn
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
| | - Paul Meredith
- Centre for Organic Photonics & Electronics, The University of Queensland, St Lucia, QLD 4072 Australia
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30
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Stolterfoht M, Armin A, Shoaee S, Kassal I, Burn P, Meredith P. Slower carriers limit charge generation in organic semiconductor light-harvesting systems. Nat Commun 2016; 7:11944. [PMID: 27324720 PMCID: PMC4919513 DOI: 10.1038/ncomms11944] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/16/2016] [Indexed: 01/28/2023] Open
Abstract
Blends of electron-donating and -accepting organic semiconductors are widely used as photoactive materials in next-generation solar cells and photodetectors. The yield of free charges in these systems is often determined by the separation of interfacial electron-hole pairs, which is expected to depend on the ability of the faster carrier to escape the Coulomb potential. Here we show, by measuring geminate and non-geminate losses and key transport parameters in a series of bulk-heterojunction solar cells, that the charge-generation yield increases with increasing slower carrier mobility. This is in direct contrast with the well-established Braun model where the dissociation rate is proportional to the mobility sum, and recent models that underscore the importance of fullerene aggregation for coherent electron propagation. The behaviour is attributed to the restriction of opposite charges to different phases, and to an entropic contribution that favours the joint separation of both charge carriers.
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Affiliation(s)
- Martin Stolterfoht
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ardalan Armin
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Safa Shoaee
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ivan Kassal
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia.,Centre for Engineered Quantum Systems, Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul Burn
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul Meredith
- Centre for Organic Photonics &Electronics, School of Mathematics and Physics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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31
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Jansen-van Vuuren RD, Armin A, Pandey AK, Burn PL, Meredith P. Organic Photodiodes: The Future of Full Color Detection and Image Sensing. Adv Mater 2016; 28:4766-4802. [PMID: 27111541 DOI: 10.1002/adma.201505405] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/16/2015] [Indexed: 06/05/2023]
Abstract
Major growth in the image sensor market is largely as a result of the expansion of digital imaging into cameras, whether stand-alone or integrated within smart cellular phones or automotive vehicles. Applications in biomedicine, education, environmental monitoring, optical communications, pharmaceutics and machine vision are also driving the development of imaging technologies. Organic photodiodes (OPDs) are now being investigated for existing imaging technologies, as their properties make them interesting candidates for these applications. OPDs offer cheaper processing methods, devices that are light, flexible and compatible with large (or small) areas, and the ability to tune the photophysical and optoelectronic properties - both at a material and device level. Although the concept of OPDs has been around for some time, it is only relatively recently that significant progress has been made, with their performance now reaching the point that they are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity. This review covers the progress made in the OPD field, describing their development as well as the challenges and opportunities.
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Affiliation(s)
- Ross D Jansen-van Vuuren
- Center for Organic Photonics & Electronics, the University of Queensland, Queensland, 4072, Australia
| | - Ardalan Armin
- Center for Organic Photonics & Electronics, the University of Queensland, Queensland, 4072, Australia
| | - Ajay K Pandey
- Center for Organic Photonics & Electronics, the University of Queensland, Queensland, 4072, Australia
| | - Paul L Burn
- Center for Organic Photonics & Electronics, the University of Queensland, Queensland, 4072, Australia
| | - Paul Meredith
- Center for Organic Photonics & Electronics, the University of Queensland, Queensland, 4072, Australia
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32
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Abstract
Lead-based organohalide perovskites have recently emerged as arguably the most promising of all next generation thin film solar cell technologies. Power conversion efficiencies have reached 20% in less than 5 years, and their application to other optoelectronic device platforms such as photodetectors and light emitting diodes is being increasingly reported. Organohalide perovskites can be solution processed or evaporated at low temperatures to form simple thin film photojunctions, thus delivering the potential for the holy grail of high efficiency, low embedded energy, and low cost photovoltaics. The initial device-driven "perovskite fever" has more recently given way to efforts to better understand how these materials work in solar cells, and deeper elucidation of their structure-property relationships. In this Account, we focus on this element of organohalide perovskite chemistry and physics in particular examining critical electro-optical, morphological, and architectural phenomena. We first examine basic crystal and chemical structure, and how this impacts important solar-cell related properties such as the optical gap. We then turn to deeper electronic phenomena such as carrier mobilities, trap densities, and recombination dynamics, as well as examining ionic and dielectric properties and how these two types of physics impact each other. The issue of whether organohalide perovskites are predominantly nonexcitonic at room temperature is currently a matter of some debate, and we summarize the evidence for what appears to be the emerging field consensus: an exciton binding energy of order 10 meV. Having discussed the important basic chemistry and physics we turn to more device-related considerations including processing, morphology, architecture, thin film electro-optics and interfacial energetics. These phenomena directly impact solar cell performance parameters such as open circuit voltage, short circuit current density, internal and external quantum efficiency, fill factor, and ultimately the all-important power conversion efficiency. Finally, we address the key challenges pertinent to actually delivering a new and viable solar cell technology. These include long-term cell stability, scaling to the module level, and the toxicity associated with lead. Organohalide perovskites not only offer exciting possibilities for next generation optoelectronics and photovoltaics, but are an intriguing class of material crossing the boundaries of molecular solids and banded inorganic semiconductors. This is a potential area of rich new chemistry, materials science, and physics.
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Affiliation(s)
- Qianqian Lin
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, and School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia 4072
| | - Ardalan Armin
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, and School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia 4072
| | - Paul L. Burn
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, and School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia 4072
| | - Paul Meredith
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, and School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia 4072
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Donaghey JE, Armin A, Stoltzfus DM, Burn PL, Meredith P. Correction: Dielectric constant enhancement of non-fullerene acceptors via side-chain modification. Chem Commun (Camb) 2016; 52:13714-13715. [DOI: 10.1039/c6cc90512a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for ‘Dielectric constant enhancement of non-fullerene acceptors via side-chain modification’ by Jenny E. Donaghey et al., Chem. Commun., 2015, 51, 14115–14118.
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Affiliation(s)
- Jenny E. Donaghey
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences and School of Mathematics and Physics
- The University of Queensland
- Brisbane 4072
- Australia
| | - Ardalan Armin
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences and School of Mathematics and Physics
- The University of Queensland
- Brisbane 4072
- Australia
| | - Dani M. Stoltzfus
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences and School of Mathematics and Physics
- The University of Queensland
- Brisbane 4072
- Australia
| | - Paul L. Burn
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences and School of Mathematics and Physics
- The University of Queensland
- Brisbane 4072
- Australia
| | - Paul Meredith
- Centre for Organic Photonics & Electronics
- School of Chemistry and Molecular Biosciences and School of Mathematics and Physics
- The University of Queensland
- Brisbane 4072
- Australia
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Donaghey JE, Armin A, Burn PL, Meredith P. Dielectric constant enhancement of non-fullerene acceptors via side-chain modification. Chem Commun (Camb) 2015; 51:14115-8. [PMID: 26255993 DOI: 10.1039/c5cc05853h] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The low dielectric constants of conventional organic semiconductors leads to poor charge carrier photogeneration in homojunction organic solar cells due to large exciton binding energies. Increasing the dielectric constant can potentially enhance the spontaneous exciton dissociation rate at room temperature in homojunction cells, and decrease the charge carrier recombination in heterojunction solar cells comprising blends of electron donors and acceptors. We report that substituting the ubiquitous alkyl solubilizing groups with short glycol chains can give non-fullerene electron acceptors with a static dielectric constant of up to 9.8.
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Affiliation(s)
- Jenny E Donaghey
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, St Lucia Campus, Brisbane 4072, Australia.
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Basiri-Esfahani S, Myers CR, Armin A, Combes J, Milburn GJ. Integrated quantum photonic sensor based on Hong-Ou-Mandel interference. Opt Express 2015; 23:16008-16023. [PMID: 26193575 DOI: 10.1364/oe.23.016008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Photonic-crystal-based integrated optical systems have been used for a broad range of sensing applications with great success. This has been motivated by several advantages such as high sensitivity, miniaturization, remote sensing, selectivity and stability. Many photonic crystal sensors have been proposed with various fabrication designs that result in improved optical properties. In parallel, integrated optical systems are being pursued as a platform for photonic quantum information processing using linear optics and Fock states. Here we propose a novel integrated Fock state optical sensor architecture that can be used for force, refractive index and possibly local temperature detection. In this scheme, two coupled cavities behave as an "effective beam splitter". The sensor works based on fourth order interference (the Hong-Ou-Mandel effect) and requires a sequence of single photon pulses and consequently has low pulse power. Changes in the parameter to be measured induce variations in the effective beam splitter reflectivity and result in changes to the visibility of interference. We demonstrate this generic scheme in coupled L3 photonic crystal cavities as an example and find that this system, which only relies on photon coincidence detection and does not need any spectral resolution, can estimate forces as small as 10(-7) Newtons and can measure one part per million change in refractive index using a very low input power of 10(-10)W. Thus linear optical quantum photonic architectures can achieve comparable sensor performance to semiclassical devices.
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Stolterfoht M, Armin A, Philippa B, White RD, Burn PL, Meredith P, Juška G, Pivrikas A. Photocarrier drift distance in organic solar cells and photodetectors. Sci Rep 2015; 5:9949. [PMID: 25919439 PMCID: PMC4412075 DOI: 10.1038/srep09949] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/23/2015] [Indexed: 11/09/2022] Open
Abstract
Light harvesting systems based upon disordered materials are not only widespread in nature, but are also increasingly prevalent in solar cells and photodetectors. Examples include organic semiconductors, which typically possess low charge carrier mobilities and Langevin-type recombination dynamics--both of which negatively impact the device performance. It is accepted wisdom that the "drift distance" (i.e., the distance a photocarrier drifts before recombination) is defined by the mobility-lifetime product in solar cells. We demonstrate that this traditional figure of merit is inadequate for describing the charge transport physics of organic light harvesting systems. It is experimentally shown that the onset of the photocarrier recombination is determined by the electrode charge and we propose the mobility-recombination coefficient product as an alternative figure of merit. The implications of these findings are relevant to a wide range of light harvesting systems and will necessitate a rethink of the critical parameters of charge transport.
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Affiliation(s)
- Martin Stolterfoht
- Centre For Organic Photonics &Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia
| | - Ardalan Armin
- Centre For Organic Photonics &Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia
| | - Bronson Philippa
- College of Science, Technology and Engineering, James Cook University, Townsville 4811, Australia
| | - Ronald D White
- College of Science, Technology and Engineering, James Cook University, Townsville 4811, Australia
| | - Paul L Burn
- Centre For Organic Photonics &Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia
| | - Paul Meredith
- Centre For Organic Photonics &Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia
| | - Gytis Juška
- Department of Solid State Electronics Vilnius University 10222 Vilnius, Lithuania
| | - Almantas Pivrikas
- 1] Centre For Organic Photonics &Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia [2] School of Engineering and Information Technology, Murdoch University, Perth 6150, Australia
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Lin Q, Armin A, Lyons DM, Burn PL, Meredith P. Low noise, IR-blind organohalide perovskite photodiodes for visible light detection and imaging. Adv Mater 2015; 27:2060-2064. [PMID: 25677496 DOI: 10.1002/adma.201405171] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/14/2014] [Indexed: 06/04/2023]
Abstract
Solution-processed organohalide perov-skite photodiodes that have performance metrics matching silicon, but are infrared-blind are reported. The perovskite photodiodes operate in the visible band, have low dark current and noise, high specific detectivity, large linear dynamic range, and fast temporal response. Their properties make them promising candidates for imaging applications.
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Affiliation(s)
- Qianqian Lin
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, 4072, Australia
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Ullah M, Armin A, Tandy K, Yambem SD, Burn PL, Meredith P, Namdas EB. Defining the light emitting area for displays in the unipolar regime of highly efficient light emitting transistors. Sci Rep 2015; 5:8818. [PMID: 25743444 PMCID: PMC4351517 DOI: 10.1038/srep08818] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 01/26/2015] [Indexed: 11/25/2022] Open
Abstract
Light-emitting field effect transistors (LEFETs) are an emerging class of multifunctional optoelectronic devices. It combines the light emitting function of an OLED with the switching function of a transistor in a single device architecture. The dual functionality of LEFETs has the potential applications in active matrix displays. However, the key problem of existing LEFETs thus far has been their low EQEs at high brightness, poor ON/OFF and poorly defined light emitting area - a thin emissive zone at the edge of the electrodes. Here we report heterostructure LEFETs based on solution processed unipolar charge transport and an emissive polymer that have an EQE of up to 1% at a brightness of 1350 cd/m2, ON/OFF ratio > 104 and a well-defined light emitting zone suitable for display pixel design. We show that a non-planar hole-injecting electrode combined with a semi-transparent electron-injecting electrode enables to achieve high EQE at high brightness and high ON/OFF ratio. Furthermore, we demonstrate that heterostructure LEFETs have a better frequency response (fcut-off = 2.6 kHz) compared to single layer LEFETs. The results presented here therefore are a major step along the pathway towards the realization of LEFETs for display applications.
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Affiliation(s)
- Mujeeb Ullah
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Ardalan Armin
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Kristen Tandy
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Soniya D Yambem
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Paul L Burn
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Paul Meredith
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
| | - Ebinazar B Namdas
- Centre for Organic Photonics &Electronics, The University of Queensland, Australia
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Armin A, Jansen-van Vuuren RD, Kopidakis N, Burn PL, Meredith P. Narrowband light detection via internal quantum efficiency manipulation of organic photodiodes. Nat Commun 2015; 6:6343. [DOI: 10.1038/ncomms7343] [Citation(s) in RCA: 332] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 01/21/2015] [Indexed: 01/23/2023] Open
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Armin A, Kassal I, Shaw PE, Hambsch M, Stolterfoht M, Lyons DM, Li J, Shi Z, Burn PL, Meredith P. Spectral dependence of the internal quantum efficiency of organic solar cells: effect of charge generation pathways. J Am Chem Soc 2014; 136:11465-72. [PMID: 25089640 DOI: 10.1021/ja505330x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conventional picture of photocurrent generation in organic solar cells involves photoexcitation of the electron donor, followed by electron transfer to the acceptor via an interfacial charge-transfer state (Channel I). It has been shown that the mirror-image process of acceptor photoexcitation leading to hole transfer to the donor is also an efficient means to generate photocurrent (Channel II). The donor and acceptor components may have overlapping or distinct absorption characteristics. Hence, different excitation wavelengths may preferentially activate one channel or the other, or indeed both. As such, the internal quantum efficiency (IQE) of the solar cell may likewise depend on the excitation wavelength. We show that several model high-efficiency organic solar cell blends, notably PCDTBT:PC70BM and PCPDTBT:PC60/70BM, exhibit flat IQEs across the visible spectrum, suggesting that charge generation is occurring either via a dominant single channel or via both channels but with comparable efficiencies. In contrast, blends of the narrow optical gap copolymer DPP-DTT with PC70BM show two distinct spectrally flat regions in their IQEs, consistent with the two channels operating at different efficiencies. The observed energy dependence of the IQE can be successfully modeled as two parallel photodiodes, each with its own energetics and exciton dynamics but both having the same extraction efficiency. Hence, an excitation-energy dependence of the IQE in this case can be explained as the interplay between two photocurrent-generating channels, without recourse to hot excitons or other exotic processes.
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Affiliation(s)
- Ardalan Armin
- Centre for Organic Photonics & Electronics (COPE), School of Mathematics and Physics, and School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane 4072, Australia
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Clulow AJ, Armin A, Lee KH, Pandey AK, Tao C, Velusamy M, James M, Nelson A, Burn PL, Gentle IR, Meredith P. Determination of fullerene scattering length density: a critical parameter for understanding the fullerene distribution in bulk heterojunction organic photovoltaic devices. Langmuir 2014; 30:1410-1415. [PMID: 24467334 DOI: 10.1021/la403951j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fullerene derivatives are commonly used as electron acceptors in combination with (macro)molecular electron donors in bulk heterojunction (BHJ) organic photovoltaic (OPV) devices. Understanding the BHJ structure at different electron donor/acceptor ratios is critical to the continued improvement and development of OPVs. The high neutron scattering length densities (SLDs) of the fullerenes provide effective contrast for probing the distribution of the fullerene within the blend in a nondestructive way. However, recent neutron scattering studies on BHJ films have reported a wide range of SLDs ((3.6-4.4) × 10(-6) Å(-2)) for the fullerenes 60-PCBM and 70-PCBM, leading to differing interpretations of their distribution in thin films. In this article, we describe an approach for determining more precisely the scattering length densities of the fullerenes within a polymer matrix in order to accurately quantify their distribution within the active layers of OPV devices by neutron scattering techniques.
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Affiliation(s)
- Andrew J Clulow
- Centre for Organic Photonics & Electronics, The University of Queensland , St. Lucia, QLD 4072, Australia
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Armin A, Zhang Y, Burn PL, Meredith P, Pivrikas A. Measuring internal quantum efficiency to demonstrate hot exciton dissociation. Nat Mater 2013; 12:593. [PMID: 23782983 DOI: 10.1038/nmat3692] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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Lauter C, Snyder M, Armin A, Jaiyesimi I, Kolins M, Burdakin J, Les K. Eosinophilic Leukemoid Reaction in a Woman with Spindle Cell Sarcoma of the Leg. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.12.238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Armour EP, White JR, Armin A, Corry PM, Coffey M, DeWitt C, Martinez A. Pulsed low dose rate brachytherapy in a rat model: dependence of late rectal injury on radiation pulse size. Int J Radiat Oncol Biol Phys 1997; 38:825-34. [PMID: 9240652 DOI: 10.1016/s0360-3016(97)89478-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE Clinical protocols utilizing pulsed low dose rate brachytherapy (PDR) to replace traditional continuous low dose rate brachytherapy (CLDR) employ irradiation in individual pulses given at intervals of a few hours. A critical factor in determining whether PDR will produce equivalent or greater late-occurring normal tissue toxicity is the dose per pulse. A rat rectal model was used to determine the role of pulse size in modifying dose effectiveness in producing late-occurring toxicity. METHODS AND MATERIALS A rat model in which the rectum is irradiated with 192Ir sources was used in conjunction with an intracavitary applicator. A section of rectum 1.3 cm in length was irradiated with either 0.75 Gy/h CLDR or one of five schemes of PDR. The schemes applied 0.375, 0.75, 1.5, 3.0, or 6.0 Gy pulses at 0.5, 1.0, 2.0, 4.0, or 8.0 h intervals, respectively. Rats were observed for up to 300 days after completion of irradiation for rectal obstruction. Rectal specimens were taken at the time of sacrifice for obstruction or at the end of follow-up and analyzed histologically for injury. RESULTS Effectiveness of irradiation was analyzed by calculating the ED50 for incidence of obstruction and severe histological injury. The ED50 for obstruction after treatment with CLDR and pulse sizes of 0.375, 0.75, and 1.5 Gy were 70.5, 68.0, 68.6, and 68.8 Gy, respectively. These values were not significantly different. Compared to CLDR, the ED50 for obstruction after pulse sizes of 3.0 and 6.0 Gy were significantly different at 60.9 and 46.3 Gy, respectively. The relative changes in ED50 for the different radiation schemes in producing ulceration, fibrosis, and vascular sclerosis injury were similar to that observed for obstruction. The endpoints of colitis cystica profunda and atypical epithelial regeneration varied less with increasing pulse size. CONCLUSIONS We have demonstrated that for late rat rectal injury, dose responses to PDR pulse sizes up to 1.5 Gy at 2-h intervals are not distinguishable from that seen with CLDR at a dose rate of 0.75 Gy/h.
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Affiliation(s)
- E P Armour
- Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI 48073, USA
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Abstract
A 67-year-old white man with esophageal adenocarcinoma presented with Peutz-Jeghers-like macules on the lips, face, nipples, and rectal mucosa. Pathological examination of the macules showed atypical melanocytes in the epidermis. The pleomorphic large melanocytes resembled the neoplastic cells seen in melanoma in situ. This is the first report of proliferation of atypical melanocytes in Peutz-Jeghers-like melanosis associated with a primary esophageal adenocarcinoma.
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Affiliation(s)
- A Eng
- Department of Pathology, Loyola University Medical Center, Maywood, Illinois 60153
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Massa MC, Greaney V, Kron T, Armin A. Malignant transformation of oral lichen planus: case report and review of the literature. Cutis 1990; 45:45-7. [PMID: 2404699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lichen planus is a mucocutaneous disorder well known to both dermatologists and dentists. Traditional belief holds that oral lichen planus predisposes to the development of squamous cell carcinoma of the oral cavity. We present a case that illustrates such a malignant transformation in a patient who smoked and had actinically damaged skin.
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Affiliation(s)
- M C Massa
- Section of Dermatology, Loyola University Medical Center, Maywood, Illinois 60153
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Abstract
Eleven biopsy specimens of Kaposi's sarcoma (KS) removed from the skin and oral mucosa were examined immunohistochemically with monoclonal antibodies PAL-E and EN-4, specific for human vascular endothelial cells, and with LN-3 monoclonal antibody reactive with immune-associated (Ia) antigens in the HLA-DR locus. The early lesions of KS, corresponding to the patch phase, contained hyperplastic venules and an increased number of lymphatic capillaries. The lymphatic capillary endothelium was reactive with EN-4, whereas, PAL-E reacted only with blood vessel endothelial cells. The spindle cells, like lymphatic endothelial cells, were non-reactive with PAL-E but showed positive reaction with EN-4 antibodies. The observed morphologic pattern of vasculogenesis and the demonstrated immune-reactivity in KS support an origin from the venule-lymphatic junction. This is an aberrant pattern but reminiscent of normal embryonal lymphatic channel development. The lymphatic capillaries and vascular slits were nonreactive with LN-3 antibody, but it was positive on cell membranes in a number of spindle cells, suggesting the focal expression of Ia-antigens.
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Affiliation(s)
- H Nadimi
- Loyola University Medical Center, Maywood, Illinois 60153
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Paloyan RG, Dado DV, Armin A. Cysticercosis. IMJ Ill Med J 1988; 173:259-61. [PMID: 2896658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Ott RA, McCall AR, McHenry C, Jarosz H, Armin A, Lawrence AM, Paloyan E. The incidence of thyroid carcinoma in Hashimoto's thyroiditis. Am Surg 1987; 53:442-5. [PMID: 3605864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The incidence of thyroid carcinoma in Hashimoto's thyroiditis has been a widely debated issue. Previous authors have reported on this topic by analyzing series of patients with Hashimoto's thyroiditis or patients with thyroid carcinoma, but not both of those populations in the same series. The population consists of a consecutive series of 800 patients operated on for thyroid nodules not associated with a radiation history. Among 161 patients with the diagnosis of thyroid carcinoma, 61 (38%) had coexistent Hashimoto's thyroiditis. In comparison, among 161 sex- and age-matched patients with colloid nodules in the same population, 18 (11%) had Hashimoto's thyroiditis. Furthermore, in the series as a whole, the incidence of Hashimoto's thyroiditis in 423 patients with colloid nodules was 10 per cent. From the perspective of the Hashimoto's thyroiditis population in the same series of 800 thyroidectomies, among 267 patients with Hashimoto's thyroiditis 61 (23%) had coexistent carcinoma. In comparison, among 267 age- and sex-matched patients with colloid nodules there were only ten coexistent carcinomas for an incidence of 4 per cent. The high incidence of carcinoma of the thyroid in Hashimoto's thyroiditis lends credence to the hypothesis that Hashimoto's thyroiditis is a predisposing factor in the development of thyroid carcinoma.
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Abstract
Multiple different tumors of follicular origin within the same patient are an infrequently reported phenomenon. We present a patient with nevus comedonicus associated with widespread, well-differentiated cutaneous tumors of follicular origin that have histologic features of trichofolliculoma, Winer's pore, and pilar sheath acanthoma.
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