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Huang YT, Nodari D, Furlan F, Zhang Y, Rusu M, Dai L, Andaji-Garmaroudi Z, Darvill D, Guo X, Rimmele M, Unold T, Heeney M, Stranks SD, Sirringhaus H, Rao A, Gasparini N, Hoye RLZ. Fast Near-Infrared Photodetectors Based on Nontoxic and Solution-Processable AgBiS 2. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2310199. [PMID: 38063859 DOI: 10.1002/smll.202310199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 11/17/2023] [Indexed: 05/03/2024]
Abstract
Solution-processable near-infrared (NIR) photodetectors are urgently needed for a wide range of next-generation electronics, including sensors, optical communications and bioimaging. However, it is rare to find photodetectors with >300 kHz cut-off frequencies, especially in the NIR region, and many of the emerging inorganic materials explored are comprised of toxic elements, such as lead. Herein, solution-processed AgBiS2 photodetectors with high cut-off frequencies under both white light (>1 MHz) and NIR (approaching 500 kHz) illumination are developed. These high cut-off frequencies are due to the short transit distances of charge-carriers in the ultrathin photoactive layer of AgBiS2 photodetectors, which arise from the strong light absorption of this material, such that film thicknesses well below 120 nm are sufficient to absorb >65% of NIR to visible light. It is also revealed that ion migration plays a critical role in the photo-response speed of these devices, and its detrimental effects can be mitigated by finely tuning the thickness of the photoactive layer, which is important for achieving low dark current densities as well. These outstanding characteristics enable the realization of air-stable, real-time heartbeat sensors based on NIR AgBiS2 photodetectors, which strongly motivates their future integration in high-throughput systems.
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Affiliation(s)
- Yi-Teng Huang
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
| | - Davide Nodari
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, White City Campus, London, W12 0BZ, UK
| | - Francesco Furlan
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, White City Campus, London, W12 0BZ, UK
| | - Youcheng Zhang
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
| | - Marin Rusu
- Struktur und Dynamik von Energiematerialien, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109, Berlin, Germany
| | - Linjie Dai
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
| | | | - Daniel Darvill
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Xiaoyu Guo
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Martina Rimmele
- KAUST Solar Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Thomas Unold
- Struktur und Dynamik von Energiematerialien, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109, Berlin, Germany
| | - Martin Heeney
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, White City Campus, London, W12 0BZ, UK
- KAUST Solar Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Samuel D Stranks
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Henning Sirringhaus
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
| | - Nicola Gasparini
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, White City Campus, London, W12 0BZ, UK
| | - Robert L Z Hoye
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
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Sabbah H, Abdel Baki Z, Mezher R, Arayro J. SCAPS-1D Modeling of Hydrogenated Lead-Free Cs 2AgBiBr 6 Double Perovskite Solar Cells with a Remarkable Efficiency of 26.3. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 14:48. [PMID: 38202505 PMCID: PMC10780520 DOI: 10.3390/nano14010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/11/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024]
Abstract
In this investigation, we employ a numerical simulation approach to model a hydrogenated lead-free Cs2AgBiBr6 double perovskite solar cell with a p-i-n inverted structure, utilizing SCAPS-1D. Contrary to traditional lead-based perovskite solar cells, the Cs2AgBiBr6 double perovskite exhibits reduced toxicity and enhanced stability, boasting a maximum power conversion efficiency of 6.37%. Given its potential for improved environmental compatibility, achieving higher efficiency is imperative for its practical implementation in solar cells. This paper offers a comprehensive quantitative analysis of the hydrogenated lead-free Cs2AgBiBr6 double perovskite solar cell, aiming to optimize its structural parameters. Our exploration involves an in-depth investigation of various electron transport layer materials to augment efficiency. Variables that affect the photovoltaic efficiency of the perovskite solar cell are closely examined, including the absorber layer's thickness and doping concentration, the hole transport layer, and the absorber defect density. We also investigate the impact of the doping concentration of the electron transport layer and the energy level alignment between the absorber and the interface on the photovoltaic output of the cell. After careful consideration, zinc oxide is chosen to serve as the electron transport layer. This optimized configuration surpasses the original structure by over four times, resulting in an impressive power conversion efficiency of 26.3%, an open-circuit voltage of 1.278 V, a fill factor of 88.21%, and a short-circuit current density of 23.30 mA.cm-2. This study highlights the critical role that numerical simulations play in improving the chances of commercializing Cs2AgBiBr6 double perovskite solar cells through increased structural optimization and efficiency.
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Affiliation(s)
- Hussein Sabbah
- College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait; (Z.A.B.); (R.M.); (J.A.)
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Lee J, Kim B, Kim C, Lee MH, Kozakci I, Cho S, Kim B, Lee SY, Kim J, Oh J, Lee JY. Unlocking the Potential of Colloidal Quantum Dot/Organic Hybrid Solar Cells: Band Tunable Interfacial Layer Approach. ACS APPLIED MATERIALS & INTERFACES 2023; 15:39408-39416. [PMID: 37555937 DOI: 10.1021/acsami.3c08419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Hybrid colloidal quantum dot (CQD)/organic architectures are promising candidates for emerging optoelectronic devices having high performance and inexpensive fabrication. For unlocking the potential of CQD/organic hybrid devices, enhancing charge extraction properties at electron transport layer (ETL)/CQD interfaces is crucial. Hence, we carefully adjust the interface properties between the ETL and CQD layer by incorporating an interfacial layer for the ETL (EIL) using several types of cinnamic acid ligands. The EIL having a cascading band offset (ΔEC) between the ETL and CQD layer suppresses the potential barrier and the local charge accumulation at ETL/CQD interfaces, thereby reducing the bimolecular recombination. An optimal EIL effectively expands the depletion region that facilitates charge extraction between the ETL and CQD layer while preventing the formation of shallow traps. Representative devices with an EIL exhibit a maximum power conversion efficiency of 14.01% and retain over 80% of initial performances after 300 h under continuous maximum power point operation.
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Affiliation(s)
- Jihyung Lee
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Byeongsu Kim
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Changjo Kim
- Information and Electronics Research Institute, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Min-Ho Lee
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Irem Kozakci
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sungjun Cho
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Beomil Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sang Yeon Lee
- Information and Electronics Research Institute, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Junho Kim
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jihun Oh
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jung-Yong Lee
- School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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Sabbah H, Baki ZA. Device Simulation of Highly Stable and 29% Efficient FA0.75MA0.25Sn0.95Ge0.05I3-Based Perovskite Solar Cell. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13091537. [PMID: 37177082 PMCID: PMC10180862 DOI: 10.3390/nano13091537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/15/2023]
Abstract
A new type of perovskite solar cell based on mixed tin and germanium has the potential to achieve good power conversion efficiency and extreme air stability. However, improving its efficiency is crucial for practical application in solar cells. This paper presents a quantitative analysis of lead-free FA0.75MA0.25Sn0.95Ge0.05I3 using a solar cell capacitance simulator to optimize its structure. Various electron transport layer materials were thoroughly investigated to enhance efficiency. The study considered the impact of energy level alignment between the absorber and electron transport layer interface, thickness and doping concentration of the electron transport layer, thickness and defect density of the absorber, and the rear metal work function. The optimized structures included poly (3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS) as the hole transport layer and either zinc oxide (ZnO) or zinc magnesium oxide (Zn0.7Mg0.3O) as the electron transport layer. The power conversion efficiency obtained was 29%, which was over three times higher than the initial structure. Performing numerical simulations on FA0.75MA0.25Sn0.95Ge0.05I3 can significantly enhance the likelihood of its commercialization. The optimized values resulting from the conducted parametric study are as follows: a short-circuit current density of 30.13 mA·cm-2), an open-circuit voltage of 1.08 V, a fill factor of 86.56%, and a power conversion efficiency of 28.31% for the intended solar cell.
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Affiliation(s)
- Hussein Sabbah
- College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait
| | - Zaher Abdel Baki
- College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait
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Fang S, Huang J, Tao R, Wei Q, Ding X, Yajima S, Chen Z, Zhu W, Liu C, Li Y, Yin N, Song L, Liu Y, Shi G, Wu H, Gao Y, Wen X, Chen Q, Shen Q, Li Y, Liu Z, Li Y, Ma W. Open-Shell Diradical-Sensitized Electron Transport Layer for High-Performance Colloidal Quantum Dot Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2212184. [PMID: 36870078 DOI: 10.1002/adma.202212184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/17/2023] [Indexed: 05/26/2023]
Abstract
The zinc oxide (ZnO) nanoparticles (NPs) are well-documented as an excellent electron transport layer (ETL) in optoelectronic devices. However, the intrinsic surface flaw of the ZnO NPs can easily result in serious surface recombination of carriers. Exploring effective passivation methods of ZnO NPs is essential to maximize the device's performance. Herein, a hybrid strategy is explored for the first time to improve the quality of ZnO ETL by incorporating stable organic open-shell donor-acceptor type diradicaloids. The high electron-donating feature of the diradical molecules can efficiently passivate the deep-level trap states and improve the conductivity of ZnO NP film. The unique advantage of the radical strategy is that its passivation effectiveness is highly correlated with the electron-donating ability of radical molecules, which can be precisely controlled by the rational design of molecular chemical structures. The well-passivated ZnO ETL is applied in lead sulfide (PbS) colloidal quantum dot solar cells, delivering a power conversion efficiency of 13.54%. More importantly, as a proof-of-concept study, this work will inspire the exploration of general strategies using radical molecules to construct high-efficiency solution-processed optoelectronic devices.
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Affiliation(s)
- Shiwen Fang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Jiaxing 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
| | - Ran Tao
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Qi Wei
- 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
| | - Xiaobo Ding
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Shota Yajima
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Zhongxin Chen
- 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
| | - Weiya Zhu
- 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
| | - Cheng Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Yusheng Li
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Ni Yin
- i-Lab, CAS Key Laboratory of Nanophotonic Materials and Devices, Suzhou Institute of Nano-Tech and Nano-Bionics, Suzhou, 215123, China
| | - Leliang Song
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Yang Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Guozheng Shi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Hao Wu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Yiyuan Gao
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Xin Wen
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Qi Chen
- i-Lab, CAS Key Laboratory of Nanophotonic Materials and Devices, Suzhou Institute of Nano-Tech and Nano-Bionics, Suzhou, 215123, China
| | - Qing Shen
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Youyong Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
| | - Zeke Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Yuan Li
- 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
| | - Wanli Ma
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
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Improving the photovoltaic performance for PbS QD thin film solar cells through interface engineering. J Colloid Interface Sci 2022; 627:562-568. [PMID: 35870408 DOI: 10.1016/j.jcis.2022.07.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 11/21/2022]
Abstract
Interfaces exist between functional layers inside thin film optoelectronic devices, and it is very important to minimize the energy loss when electrons move across the interfaces to improve the photovoltaic performance. For PbS quantum dots (QDs) solar cells with the classical n-i-p device architecture, it is particularly challenging to tune the electron transfer process due to limited material choices for each functional layer. Here, we introduce materials to tune the electron transfer across the three interfaces inside the PbS-QD solar cell: (1) the interface between the ZnO electron transport layer and the n-type iodide capped PbS QD layer (PbS-I QD layer), (2) the interface between the n-type PbS-I layer and the p-type 1,2-ethanedithiol (EDT) treated PbS QD layer (PbS-EDT QD layer), (3) the interface between the PbS-EDT layer and the Au electrode. After passivating the ZnO layer through APTES treating; tuning the band alignment through varying the QD size of PbS -EDT QD layer and a carbazole layer to tune the hole transport process, a power conversion efficiency of 9.23% (Voc of 0.62 V) under simulated AM1.5 sunlight is demonstrated for PbS QD solar cells. Our results highlights the profound influence of interface engineering on the electron transfer inside the PbS QD solar cells, exemplified by its impact on the photovoltaic performance of PbS QD devices.
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7
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Yuan M, Wang X, Chen X, He J, Li K, Song B, Hu H, Gao L, Lan X, Chen C, Tang J. Phase-Transfer Exchange Lead Chalcogenide Colloidal Quantum Dots: Ink Preparation, Film Assembly, and Solar Cell Construction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2102340. [PMID: 34561947 DOI: 10.1002/smll.202102340] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/23/2021] [Indexed: 06/13/2023]
Abstract
Solution-processed colloidal quantum dots (CQDs) are promising candidates for the third-generation photovoltaics due to their low cost and spectral tunability. The development of CQD solar cells mainly relies on high-quality CQD ink, smooth and dense film, and charge-extraction-favored device architectures. In particular, advances in the processing of CQDs are essential for high-quality QD solids. The phase transfer exchange (PTE), in contrast with traditional solid-state ligand exchange, has demonstrated to be the most promising approach for high-quality QD solids in terms of charge transport and defect passivation. As a result, the efficiencies of Pb chalcogenide CQD solar cells have been rapidly improved to 14.0%. In this review, the development of the PTE method is briefly reviewed for lead chalcogenide CQD ink preparation, film assembly, and device construction. Particularly, the key roles of lead halides and additional additives are emphasized for defect passivation and charge transport improvement. In the end, several potential directions for future research are proposed.
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Affiliation(s)
- Mohan Yuan
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Xia Wang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Xiao Chen
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Jungang He
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Kanghua Li
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Boxiang Song
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Huicheng Hu
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Liang Gao
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Xinzheng Lan
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Chao Chen
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Jiang Tang
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
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8
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Armstrong C, Delumeau LV, Muñoz-Rojas D, Kursumovic A, MacManus-Driscoll J, Musselman KP. Tuning the band gap and carrier concentration of titania films grown by spatial atomic layer deposition: a precursor comparison. NANOSCALE ADVANCES 2021; 3:5908-5918. [PMID: 34746646 PMCID: PMC8507900 DOI: 10.1039/d1na00563d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Spatial atomic layer deposition retains the advantages of conventional atomic layer deposition: conformal, pinhole-free films and excellent control over thickness. Additionally, it allows higher deposition rates and is well-adapted to depositing metal oxide nanofilms for photovoltaic cells and other devices. This study compares the morphological, electrical and optical properties of titania thin films deposited by spatial atomic layer deposition from titanium isopropoxide (TTIP) and titanium tetrachloride (TiCl4) over the temperature range 100-300 °C, using the oxidant H2O. Amorphous films were deposited at temperatures as low as 100 °C from both precursors: the approach is suitable for applying films to temperature-sensitive devices. An amorphous-to-crystalline transition temperature was observed for both precursors resulting in surface roughening, and agglomerates for TiCl4. Both precursors formed conformal anatase films at 300 °C, with growth rates of 0.233 and 0.153 nm s-1 for TiCl4 and TTIP. A drawback of TiCl4 use is the HCl by-product, which was blamed for agglomeration in the films. Cl contamination was the likely cause of band gap narrowing and higher defect densities compared to TTIP-grown films. The carrier concentration of the nanofilms was found to increase with deposition temperature. The films were tested in hybrid bilayer solar cells to demonstrate their appropriateness for photovoltaic devices.
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Affiliation(s)
- Claire Armstrong
- Department of Materials Science & Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Louis-Vincent Delumeau
- Department of Mechanical and Mechatronics Engineering, University of Waterloo 200 University Ave. West Waterloo Canada
- Waterloo Institute for Nanotechnology 200 University Ave. West Waterloo Canada
| | - David Muñoz-Rojas
- Laboratoire des Materiaux et du Genie Physique, CNRS, MINATEC 3 Parvis Louis Neel Grenoble 38016 France
| | - Ahmed Kursumovic
- Department of Materials Science & Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Judith MacManus-Driscoll
- Department of Materials Science & Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Kevin P Musselman
- Department of Mechanical and Mechatronics Engineering, University of Waterloo 200 University Ave. West Waterloo Canada
- Waterloo Institute for Nanotechnology 200 University Ave. West Waterloo Canada
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9
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Liu J, Xian K, Ye L, Zhou Z. Open-Circuit Voltage Loss in Lead Chalcogenide Quantum Dot Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008115. [PMID: 34085736 DOI: 10.1002/adma.202008115] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/09/2021] [Indexed: 06/12/2023]
Abstract
Lead chalcogenide colloidal quantum dot solar cells (CQDSCs) have received considerable attention due to their broad and tunable absorption and high stability. Presently, lead chalcogenide CQDSC has achieved a power conversion efficiency of ≈14%. However, the state-of-the-art lead chalcogenide CQDSC still has an open-circuit voltage (Voc ) loss of ≈0.45 V, which is significantly higher than those of c-Si and perovskite solar cells. Such high Voc loss severely limits the performance improvement and commercialization of lead chalcogenide CQDSCs. In this review, the Voc loss is first analyzed via detailed balance theory and the origin of Voc loss from both solar absorber and interface is summarized. Subsequently, various strategies for improving the Voc from the solar absorber, including the passivation strategies during the synthesis and ligand exchange are overviewed. The great impact of the ligand exchange process on CQD passivation is highlighted and the corresponding strategies to further reduce the Voc loss are summarized. Finally, various strategies are discussed to reduce interface Voc loss from charge transport layers. More importantly, the great potential of achieving performance breakthroughs via various organic hole transport layers is highlighted and the existing challenges toward commercialization are discussed.
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Affiliation(s)
- Junwei Liu
- School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Kaihu Xian
- School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Long Ye
- School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Zhihua Zhou
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
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10
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Yang Y, Su L, Feng N, Liu A, Xing X, Lu M, Yu WW. Balanced charge transport and enhanced performance of blue quantum dot light-emitting diodes via electron transport layer doping. NANOTECHNOLOGY 2021; 32:335203. [PMID: 33971629 DOI: 10.1088/1361-6528/abff8c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
The unbalanced charge transport is always a key influencing factor on the device performance of quantum dot light-emitting diodes (QLEDs), particularly for the blue QLEDs due to their large optical band gap. Here, a method of electron transport layer (ETL) doping was developed to regulate the energy levels and the carrier mobility of the ETL, which resulted in more balanced charge injection, transport and recombination in the blue emitting CdZnS/ZnS core/shell QLEDs. Consequently, an enhanced performance of blue QLEDs was achieved by modulating the charge balance through ETL doping. The maximum external quantum efficiency and luminance was dramatically increased from 2.2% to 7.3% and from 3786 cd m-2to 9108 cd m-2, respectively. The results illustrate that charge transport layer doping is a simple and effective strategy to regulate the charge injection barrier and carrier mobility of QLEDs.
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Affiliation(s)
- Yue Yang
- State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
| | - Liang Su
- State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
| | - Nannan Feng
- State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
| | - Anqi Liu
- State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
| | - Xiaoxue Xing
- College of Electronic Information Engineering, Changchun University, Changchun 130022, People's Republic of China
| | - Min Lu
- State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
| | - William W Yu
- Department of Chemistry and Physics, Louisiana State University, Shreveport, LA 71115, United States of America
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11
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Mistry K, Jones A, Kao M, Yeow TWK, Yavuz M, Musselman KP. In-situ observation of nucleation and property evolution in films grown with an atmospheric pressure spatial atomic layer deposition system. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/ab976c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Abstract
Atmospheric pressure—spatial atomic layer deposition (AP-SALD) is a promising open-air deposition technique for high-throughput manufacturing of nanoscale films, yet the nucleation and property evolution in these films has not been studied in detail. In this work, in situ reflectance spectroscopy was implemented in an AP-SALD system to measure the properties of Zinc oxide (ZnO) and Aluminum oxide (Al2O3) films during their deposition. For the first time, this revealed a substrate nucleation period for this technique, where the length of the nucleation time was sensitive to the deposition parameters. The in situ characterization of thickness showed that varying the deposition parameters can achieve a wide range of growth rates (0.1–3 nm/cycle), and the evolution of optical properties throughout film growth was observed. For ZnO, the initial bandgap increased when deposited at lower temperatures and subsequently decreased as the film thickness increased. Similarly, for Al2O3 the refractive index was lower for films deposited at a lower temperature and subsequently increased as the film thickness increased. Notably, where other implementations of reflectance spectroscopy require previous knowledge of the film’s optical properties to fit the spectra to optical dispersion models, the approach developed here utilizes a large range of initial guesses that are inputted into a Levenberg-Marquardt fitting algorithm in parallel to accurately determine both the film thickness and complex refractive index.
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12
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Physical Properties of Sn-Doped PbSe Nanostructures as Photovoltaic Application. J Inorg Organomet Polym Mater 2020. [DOI: 10.1007/s10904-019-01261-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Kim M, Han CY, Yang H, Park B. Band to Band Tunneling at the Zinc Oxide (ZnO) and Lead Selenide (PbSe) Quantum Dot Contact; Interfacial Charge Transfer at a ZnO/PbSe/ZnO Probe Device. MATERIALS 2019; 12:ma12142289. [PMID: 31319559 PMCID: PMC6678409 DOI: 10.3390/ma12142289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/11/2019] [Accepted: 07/15/2019] [Indexed: 11/16/2022]
Abstract
We provide a comprehensive understanding of interfacial charge transfer at the lead selenide (PbSe) quantum dot (QD)/zinc oxide (ZnO) interface, proposing band to band tunneling process as a charge transfer mechanism in which initial hopping of carriers from ZnO to PbSe QDs is independent of temperature. Using the transmission line method (TLM) in a ZnO/PbSe/ZnO geometry device, we measured the ZnO/PbSe electrical contact resistance, a measure of charge transfer efficiency. Fabrication of a highly conductive ZnO film through Al doping allows for the formation of ZnO source and drain electrodes, replacing conventional metal electrodes. We found that band to band tunneling at the PbSe QD/ZnO interface governs charge transfer based on temperature-independent PbSe QD/ZnO contact resistance. In contrast, the PbSe QD channel sheet resistance decreased as the temperature increased, indicating thermally activated transport process in the PbSe QD film. These results demonstrate that, at the ZnO/PbSe QD interface, temperature-independent tunneling process initiates carrier injection followed by thermally activated carrier hopping, determining the electrical contact resistance.
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Affiliation(s)
- Minkyong Kim
- Department of Materials Science and Engineering, Hongik University 72-1, Sangsu-dong, Mapo-gu, Seoul 04066, Korea
| | - Chang-Yeol Han
- Department of Materials Science and Engineering, Hongik University 72-1, Sangsu-dong, Mapo-gu, Seoul 04066, Korea
| | - Heesun Yang
- Department of Materials Science and Engineering, Hongik University 72-1, Sangsu-dong, Mapo-gu, Seoul 04066, Korea.
| | - Byoungnam Park
- Department of Materials Science and Engineering, Hongik University 72-1, Sangsu-dong, Mapo-gu, Seoul 04066, Korea.
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14
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Gao Y, Patterson R, Hu L, Yuan L, Zhang Z, Hu Y, Chen Z, Teh ZL, Conibeer G, Huang S. MgCl 2 passivated ZnO electron transporting layer to improve PbS quantum dot solar cells. NANOTECHNOLOGY 2019; 30:085403. [PMID: 30248023 DOI: 10.1088/1361-6528/aae3de] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The unique tunable bandgaps and straightforward synthesis of colloidal quantum dots make them promising low-cost materials for photovoltaics. High-performance colloidal quantum dot solar cells rely on good-quality electron transporting layers (ETLs) to make carrier selective contacts. Despite extensive use of n-type oxides as ETLs, a detailed understanding of their surface and interface states as well as mechanisms to improve their optical properties are still under development. Here, we report a simple procedure to produce MgCl2 passivated ZnO nanoparticles ETLs that show improved device performance. The MgCl2 treated ZnO electron transporting layers boost the PbS colloidal quantum dot cell efficiency from 6.3% to 8.2%. The cell exhibits reduced defects leading to significant improvements of both FF and J sc. This low-temperature MgCl2 treated ZnO electron transporting layer may be applied in solution processed tandem cells as a promising strategy to further increase cell efficiencies.
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Affiliation(s)
- Yijun Gao
- Australian Centre for Advanced Photovoltaics, School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
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15
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Ding C, Zhang Y, Liu F, Kitabatake Y, Hayase S, Toyoda T, Wang R, Yoshino K, Minemoto T, Shen Q. Understanding charge transfer and recombination by interface engineering for improving the efficiency of PbS quantum dot solar cells. NANOSCALE HORIZONS 2018; 3:417-429. [PMID: 32254129 DOI: 10.1039/c8nh00030a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In quantum dot heterojunction solar cells (QDHSCs), the QD active layer absorbs sunlight and then transfers the photogenerated electrons to an electron-transport layer (ETL). It is generally believed that the conduction band minimum (CBM) of the ETL should be lower than that of the QDs to enable efficient charge transfer from the QDs to the collection electrode (here, FTO) through the ETL. However, by employing Mg-doped ZnO (Zn1-xMgxO) as a model ETL in PbS QDHSCs, we found that an ETL with a lower CBM is not necessary to realize efficient charge transfer in QDHSCs. The existence of shallow defect states in the Zn1-xMgxO ETL can serve as additional charge-transfer pathways. In addition, the conduction band offset (CBO) between the ETL and the QD absorber has been, for the first time, revealed to significantly affect interfacial recombination in QDHSCs. We demonstrate that a spike in the band structure at the ETL/QD interface is useful for suppressing interfacial recombination and improving the open-circuit voltage. By varying the Mg doping level in ZnO, we were able to tune the CBM, defect distribution and carrier concentration in the ETL, which play key roles in charge transfer and recombination and therefore the device performance. PbS QDHSCs based on the optimized Zn1-xMgxO ETL exhibited a high power conversion efficiency of 10.6%. Our findings provide important guidance for enhancing the photovoltaic performance of QD-based solar cells.
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Affiliation(s)
- Chao Ding
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
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16
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Prasad AK, Jain M. Breakdown of Kasha's Rule in a Ubiquitous, Naturally Occurring, Wide Bandgap Aluminosilicate (Feldspar). Sci Rep 2018; 8:810. [PMID: 29339737 PMCID: PMC5770446 DOI: 10.1038/s41598-017-17466-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/27/2017] [Indexed: 11/08/2022] Open
Abstract
Excitation-energy-dependent emission (EDE) is well known from photoluminescence (PL) studies of polar solvents and carbon-based nanostructures. In polar solvents, this effect known as the 'red edge effect' (REE) is understood to arise from solute-solvent interactions, whereas, in case of carbon-based nanostructures, the origin is highly debated. Understanding this effect has important bearings on the potential applications of these materials. EDE has never been reported from large crystalline materials, except very recently by our group. Here, we make detailed investigations to understand the universality and the mechanism behind the EDE in a wide band gap aluminosilicate (feldspar), which comprises more than half of the Earth's crust, and is widely used in geophotonics (e.g., optical dating). We observe EDE up to 150 nm at room temperature in our samples, which is unprecedented in rigid macroscopic structures. Based on PL investigations at 295 K and 7 K, we present a novel model that is based on photoionisation of a deep lying defect and subsequent transport/relaxation of free electrons in the sub-conduction band tail states. Our model has important implications for potential photonic applications using feldspar, measurement of band tail width in wide bandgap materials, and understanding the EDE effect in other materials.
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Affiliation(s)
- Amit Kumar Prasad
- Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, Roskilde, 4000, Denmark.
- Schulich Faculty of Chemistry and Solid State Institute, Technion-Israel Institute of Technology, Haifa, 32000, Israel.
| | - Mayank Jain
- Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, Roskilde, 4000, Denmark
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17
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Tang N, Li Y, Chen F, Han Z. In situ fabrication of a direct Z-scheme photocatalyst by immobilizing CdS quantum dots in the channels of graphene-hybridized and supported mesoporous titanium nanocrystals for high photocatalytic performance under visible light. RSC Adv 2018; 8:42233-42245. [PMID: 35558760 PMCID: PMC9092058 DOI: 10.1039/c8ra08008a] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/23/2018] [Indexed: 12/22/2022] Open
Abstract
We report the considerable advantages of direct Z-scheme photocatalysts by immobilizing high-quality CdS quantum dots (QDs) in the channels of graphene-hybridized and supported mesoporous titania (GMT) nanocrystals (CdS@GMT/GR) under facile hydrothermal conditions. The photocatalysts have been characterized by XRD, PL, XPS, SEM, DRS, TEM, EIS, and N2 adsorption. CdS QDs primarily serve as photosensitizers with a unique pore-embedded structure for the effective utilization of the light source. This direct Z-scheme CdS@GMT/GR exhibits higher photocatalytic activity than CdS/GR, GMT/GR, or CdS@MT. In addition, the rate constant of CdS@GMT/GR-2 is approximately twice the sum of those of CdS@MT and GMT/GR, because GR played the role of hole-transporting and collection layer as well as the hybridization level formation in terms of hybridizing MT and serving as a support. Therefore, the GR content tunes the energy band, affects the surface area, and controls the interfacial hole transfer and collection rate of the direct Z-scheme system. Furthermore, CdS@GMT/GR retains its high performance in repeated photocatalytic processes. This can be attributed to the fact that GR prevents QDs from photocorrosion by means of the hole-transporting and collection effect. A possible reaction mechanism is proposed. This work provides a promising strategy for the construction of highly efficient visible-light-driven photocatalysts to reduce the growing menace of environmental pollution. CdS@GMT/GR exhibits high photocatalytic activity due to its direct Z-scheme structure obtained by immobilizing CdS quantum dots in the channels of GMT nanocrystals.![]()
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Affiliation(s)
- Ningmei Tang
- College of Chemistry and Chemical Engineering
- Jishou University
- P. R. China
| | - Youji Li
- College of Chemistry and Chemical Engineering
- Jishou University
- P. R. China
| | - Feitai Chen
- College of Chemistry and Chemical Engineering
- Jishou University
- P. R. China
| | - Zhenying Han
- College of Chemistry and Chemical Engineering
- Jishou University
- P. R. China
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18
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Hoye RLZ, Lee LC, Kurchin RC, Huq TN, Zhang KHL, Sponseller M, Nienhaus L, Brandt RE, Jean J, Polizzotti JA, Kursumović A, Bawendi MG, Bulović V, Stevanović V, Buonassisi T, MacManus-Driscoll JL. Strongly Enhanced Photovoltaic Performance and Defect Physics of Air-Stable Bismuth Oxyiodide (BiOI). ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1702176. [PMID: 28715091 DOI: 10.1002/adma.201702176] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Bismuth-based compounds have recently gained increasing attention as potentially nontoxic and defect-tolerant solar absorbers. However, many of the new materials recently investigated show limited photovoltaic performance. Herein, one such compound is explored in detail through theory and experiment: bismuth oxyiodide (BiOI). BiOI thin films are grown by chemical vapor transport and found to maintain the same tetragonal phase in ambient air for at least 197 d. The computations suggest BiOI to be tolerant to antisite and vacancy defects. All-inorganic solar cells (ITO|NiOx |BiOI|ZnO|Al) with negligible hysteresis and up to 80% external quantum efficiency under select monochromatic excitation are demonstrated. The short-circuit current densities and power conversion efficiencies under AM 1.5G illumination are nearly double those of previously reported BiOI solar cells, as well as other bismuth halide and chalcohalide photovoltaics recently explored by many groups. Through a detailed loss analysis using optical characterization, photoemission spectroscopy, and device modeling, direction for future improvements in efficiency is provided. This work demonstrates that BiOI, previously considered to be a poor photocatalyst, is promising for photovoltaics.
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Affiliation(s)
- Robert L Z Hoye
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, UK
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Lana C Lee
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
| | - Rachel C Kurchin
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tahmida N Huq
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
| | - Kelvin H L Zhang
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
| | | | - Lea Nienhaus
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Riley E Brandt
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Joel Jean
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Ahmed Kursumović
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
| | - Moungi G Bawendi
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Vladimir Bulović
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Vladan Stevanović
- Colorado School of Mines, Golden, CO, 80401, USA
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Tonio Buonassisi
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Judith L MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK
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19
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Choi J, Kim Y, Jo JW, Kim J, Sun B, Walters G, García de Arquer FP, Quintero-Bermudez R, Li Y, Tan CS, Quan LN, Kam APT, Hoogland S, Lu Z, Voznyy O, Sargent EH. Chloride Passivation of ZnO Electrodes Improves Charge Extraction in Colloidal Quantum Dot Photovoltaics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28671721 DOI: 10.1002/adma.201702350] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/28/2017] [Indexed: 05/04/2023]
Abstract
The tunable bandgap of colloidal quantum dots (CQDs) makes them an attractive material for photovoltaics (PV). The best present-day CQD PV devices employ zinc oxide (ZnO) as an electron transport layer; however, it is found herein that ZnO's surface defect sites and unfavorable electrical band alignment prevent devices from realizing their full potential. Here, chloride (Cl)-passivated ZnO generated from a solution of presynthesized ZnO nanoparticles treated using an organic-solvent-soluble Cl salt is reported. These new ZnO electrodes exhibit decreased surface trap densities and a favorable electronic band alignment, improving charge extraction from the CQD layer and achieving the best-cell power conversion efficiency (PCE) of 11.6% and an average PCE of 11.4 ± 0.2%.
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Affiliation(s)
- Jongmin Choi
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Younghoon Kim
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Jea Woong Jo
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Junghwan Kim
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Bin Sun
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Grant Walters
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - F Pelayo García de Arquer
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Rafael Quintero-Bermudez
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Yiying Li
- Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario, M5S 3E4, Canada
| | - Chih Shan Tan
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Li Na Quan
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Andrew Pak Tao Kam
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Sjoerd Hoogland
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Zhenghong Lu
- Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario, M5S 3E4, Canada
| | - Oleksandr Voznyy
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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20
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Musselman KP, Muñoz-Rojas D, Hoye RLZ, Sun H, Sahonta SL, Croft E, Böhm ML, Ducati C, MacManus-Driscoll JL. Rapid open-air deposition of uniform, nanoscale, functional coatings on nanorod arrays. NANOSCALE HORIZONS 2017; 2:110-117. [PMID: 32260672 DOI: 10.1039/c6nh00197a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Coating of high-aspect-ratio nanostructures has previously been achieved using batch processes poorly suited for high-throughput manufacturing. It is demonstrated that uniform, nanoscale coatings can be rapidly deposited on zinc oxide nanorod arrays in open-air using an atmospheric pressure spatial deposition system. The morphology of the metal oxide coatings is examined and good electrical contact with the underlying nanorods is observed. The functionality of the coatings is demonstrated in colloidal quantum dot and hybrid solar cells.
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Affiliation(s)
- K P Musselman
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo, N2L 3G1, Canada.
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21
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Hinzmann C, Magen O, Hofstetter YJ, Hopkinson PE, Tessler N, Vaynzof Y. Effect of Injection Layer Sub-Bandgap States on Electron Injection in Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2017; 9:6220-6227. [PMID: 28098451 DOI: 10.1021/acsami.6b14594] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
It is generally considered that the injection of charges into an active layer of an organic light-emitting diode (OLED) is solely determined by the energetic injection barrier formed at the device interfaces. Here, we demonstrate that the density of surface states of the electron-injecting ZnO layer has a profound effect on both the charge injection and the overall performance of the OLED device. Introducing a dopant into ZnO reduces both the energy depth and density of surface states without altering the position of the energy levels-thus, the magnitude of the injection barrier formed at the organic/ZnO interface remains unchanged. Changes observed in the density of surface states result in an improved electron injection and enhanced luminescence of the device. We implemented a numerical simulation, modeling the effects of energetics and the density of surface states on the electron injection, demonstrating that both contributions should be considered when choosing the appropriate injection layer.
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Affiliation(s)
| | - Osnat Magen
- Sara and Moshe Zisapel Nano-Electronic Center, Department of Electrical Engineering, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | | | | | - Nir Tessler
- Sara and Moshe Zisapel Nano-Electronic Center, Department of Electrical Engineering, Technion-Israel Institute of Technology , Haifa 32000, Israel
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22
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Crisp RW, Pach GF, Kurley JM, France RM, Reese MO, Nanayakkara SU, MacLeod BA, Talapin DV, Beard MC, Luther JM. Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe-ZnO Tunnel Junction. NANO LETTERS 2017; 17:1020-1027. [PMID: 28068765 DOI: 10.1021/acs.nanolett.6b04423] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We developed a monolithic CdTe-PbS tandem solar cell architecture in which both the CdTe and PbS absorber layers are solution-processed from nanocrystal inks. Due to their tunable nature, PbS quantum dots (QDs), with a controllable band gap between 0.4 and ∼1.6 eV, are a promising candidate for a bottom absorber layer in tandem photovoltaics. In the detailed balance limit, the ideal configuration of a CdTe (Eg = 1.5 eV)-PbS tandem structure assumes infinite thickness of the absorber layers and requires the PbS band gap to be 0.75 eV to theoretically achieve a power conversion efficiency (PCE) of 45%. However, modeling shows that by allowing the thickness of the CdTe layer to vary, a tandem with efficiency over 40% is achievable using bottom cell band gaps ranging from 0.68 and 1.16 eV. In a first step toward developing this technology, we explore CdTe-PbS tandem devices by developing a ZnTe-ZnO tunnel junction, which appropriately combines the two subcells in series. We examine the basic characteristics of the solar cells as a function of layer thickness and bottom-cell band gap and demonstrate open-circuit voltages in excess of 1.1 V with matched short circuit current density of 10 mA/cm2 in prototype devices.
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Affiliation(s)
- Ryan W Crisp
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
- Department of Physics, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Gregory F Pach
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
- Department of Electrical, Computer, and Energy Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - J Matthew Kurley
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
| | - Ryan M France
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Matthew O Reese
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | | | - Bradley A MacLeod
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Dmitri V Talapin
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Matthew C Beard
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Joseph M Luther
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
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23
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Ou KL, Ehamparam R, MacDonald G, Stubhan T, Wu X, Shallcross RC, Richards R, Brabec CJ, Saavedra SS, Armstrong NR. Characterization of ZnO Interlayers for Organic Solar Cells: Correlation of Electrochemical Properties with Thin-Film Morphology and Device Performance. ACS APPLIED MATERIALS & INTERFACES 2016; 8:19787-19798. [PMID: 27362429 DOI: 10.1021/acsami.6b02792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This report focuses on the evaluation of the electrochemical properties of both solution-deposited sol-gel (sg-ZnO) and sputtered (sp-ZnO) zinc oxide thin films, intended for use as electron-collecting interlayers in organic solar cells (OPVs). In the electrochemical studies (voltammetric and impedance studies), we used indium-tin oxide (ITO) over coated with either sg-ZnO or sp-ZnO interlayers, in contact with either plain electrolyte solutions, or solutions with probe redox couples. The electroactive area of exposed ITO under the ZnO interlayer was estimated by characterizing the electrochemical response of just the oxide interlayer and the charge transfer resistance from solutions with the probe redox couples. Compared to bare ITO, the effective electroactive area of ITO under sg-ZnO films was ca. 70%, 10%, and 0.3% for 40, 80, and 120 nm sg-ZnO films. More compact sp-ZnO films required only 30 nm thicknesses to achieve an effective electroactive ITO area of ca. 0.02%. We also examined the electrochemical responses of these same ITO/ZnO heterojunctions overcoated with device thickness pure poly(3-hexylthiophehe) (P3HT), and donor/acceptor blended active layers (P3HT:PCBM). Voltammetric oxidation/reduction of pure P3HT thin films on ZnO/ITO contacts showed that pinhole pathways exist in ZnO films that permit dark oxidation (ITO hole injection into P3HT). In P3HT:PCBM active layers, however, the electrochemical activity for P3HT oxidation is greatly attenuated, suggesting PCBM enrichment near the ZnO interface, effectively blocking P3HT interaction with the ITO contact. The shunt resistance, obtained from dark current-voltage behavior in full P3HT/PCBM OPVs, was dependent on both (i) the porosity of the sg-ZnO or sp-ZnO films (as revealed by probe molecule electrochemistry) and (ii) the apparent enrichment of PCBM at ZnO/P3HT:PCBM interfaces, both effects conveniently revealed by electrochemical characterization. We anticipate that these approaches will be applicable to a wider array of solution-processed interlayers for "printable" solar cells.
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Affiliation(s)
- Kai-Lin Ou
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Ramanan Ehamparam
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Gordon MacDonald
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Tobias Stubhan
- Institute of Materials for Electronics and Energy Technology, Friedrich-Alexander-University Erlangen-Nuremberg , Martensstrasse 7, 91058 Erlangen, Germany
| | - Xin Wu
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - R Clayton Shallcross
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Robin Richards
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Christoph J Brabec
- Institute of Materials for Electronics and Energy Technology, Friedrich-Alexander-University Erlangen-Nuremberg , Martensstrasse 7, 91058 Erlangen, Germany
| | - S Scott Saavedra
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Neal R Armstrong
- Department of Chemistry & Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
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24
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Ievskaya Y, Hoye RLZ, Sadhanala A, Musselman KP, MacManus-Driscoll JL. Improved Heterojunction Quality in Cu2O-based Solar Cells Through the Optimization of Atmospheric Pressure Spatial Atomic Layer Deposited Zn1-xMgxO. J Vis Exp 2016. [PMID: 27500923 PMCID: PMC5091704 DOI: 10.3791/53501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Atmospheric pressure spatial atomic layer deposition (AP-SALD) was used to deposit n-type ZnO and Zn1-xMgxO thin films onto p-type thermally oxidized Cu2O substrates outside vacuum at low temperature. The performance of photovoltaic devices featuring atmospherically fabricated ZnO/Cu2O heterojunction was dependent on the conditions of AP-SALD film deposition, namely, the substrate temperature and deposition time, as well as on the Cu2O substrate exposure to oxidizing agents prior to and during the ZnO deposition. Superficial Cu2O to CuO oxidation was identified as a limiting factor to heterojunction quality due to recombination at the ZnO/Cu2O interface. Optimization of AP-SALD conditions as well as keeping Cu2O away from air and moisture in order to minimize Cu2O surface oxidation led to improved device performance. A three-fold increase in the open-circuit voltage (up to 0.65 V) and a two-fold increase in the short-circuit current density produced solar cells with a record 2.2% power conversion efficiency (PCE). This PCE is the highest reported for a Zn1-xMgxO/Cu2O heterojunction formed outside vacuum, which highlights atmospheric pressure spatial ALD as a promising technique for inexpensive and scalable fabrication of Cu2O-based photovoltaics.
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Affiliation(s)
- Yulia Ievskaya
- Department of Materials Science and Metallurgy, University of Cambridge;
| | - Robert L Z Hoye
- Department of Materials Science and Metallurgy, University of Cambridge
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25
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Scheunemann D, Wilken S, Parisi J, Borchert H. Charge carrier loss mechanisms in CuInS2/ZnO nanocrystal solar cells. Phys Chem Chem Phys 2016; 18:16258-65. [PMID: 27250665 DOI: 10.1039/c6cp01015f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heterojunction solar cells based on colloidal nanocrystals (NCs) have shown remarkable improvements in performance in the last decade, but this progress is limited to merely two materials, PbS and PbSe. However, solar cells based on other material systems such as copper-based compounds show lower power conversion efficiencies and much less effort has been made to develop a better understanding of factors limiting their performance. Here, we study charge carrier loss mechanisms in solution-processed CuInS2/ZnO NC solar cells by combining steady-state measurements with transient photocurrent and photovoltage measurements. We demonstrate the presence of an extraction barrier at the CuInS2/ZnO interface, which can be reduced upon illumination with UV light. However, trap-assisted recombination in the CuInS2 layer is shown to be the dominant decay process in these devices.
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Affiliation(s)
- Dorothea Scheunemann
- Energy and Semiconductor Research Laboratory, Department of Physics, University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany.
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26
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Ultrasensitive photoelectrochemical aptasensing of miR-155 using efficient and stable CH3NH3PbI3 quantum dots sensitized ZnO nanosheets as light harvester. Biosens Bioelectron 2016; 85:142-150. [PMID: 27162145 DOI: 10.1016/j.bios.2016.04.099] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/28/2016] [Accepted: 04/29/2016] [Indexed: 11/22/2022]
Abstract
An ultrasensitive photoelectrochemical (PEC) aptasensor based on a novel signal amplification strategy was developed for the quantitative determination of microRNA (miR)-155. CH3NH3PbI3 quantum dots (QDs) functionalized ZnO nanosheets (NSs) were employed as the light harvester. Owing to the synergetic effect between CH3NH3PbI3 QDs and ZnO NSs, ZnO@CH3NH3PbI3 can provide an obviously increasing PEC signal by forming the heterojunction. Due to the larger steric hindrance, the sensitive decrease of the PEC signal can be achieved by the specific recognition between the primers and ssDNA of miR-155. In this sense, this developed aptasensor can achieve a high sensitivity (especially in the presence of the low concentrations of miR-155) and a wide detection range (0.01fmol/L to 20,000pmol/L). Under the optimal conditions, the proposed aptasensor offered an ultrasensitive and specific determination of miR-155 down to 0.005fmol/L. This aptassay method would open up a new promising platform at ultralow levels for early diagnose of different miRNA.
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27
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Armstrong CL, Price MB, Muñoz-Rojas D, Davis NJKL, Abdi-Jalebi M, Friend RH, Greenham NC, MacManus-Driscoll JL, Böhm ML, Musselman KP. Influence of an Inorganic Interlayer on Exciton Separation in Hybrid Solar Cells. ACS NANO 2015; 9:11863-71. [PMID: 26548399 PMCID: PMC4690195 DOI: 10.1021/acsnano.5b05934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/08/2015] [Indexed: 05/26/2023]
Abstract
It has been shown that in hybrid polymer-inorganic photovoltaic devices not all the photogenerated excitons dissociate at the interface immediately, but can instead exist temporarily as bound charge pairs (BCPs). Many of these BCPs do not contribute to the photocurrent, as their long lifetime as a bound species promotes various charge carrier recombination channels. Fast and efficient dissociation of BCPs is therefore considered a key challenge in improving the performance of polymer-inorganic cells. Here we investigate the influence of an inorganic energy cascading Nb2O5 interlayer on the charge carrier recombination channels in poly(3-hexylthiophene-2,5-diyl) (P3HT)-TiO2 and PbSe colloidal quantum dot-TiO2 photovoltaic devices. We demonstrate that the additional Nb2O5 film leads to a suppression of BCP formation at the heterojunction of the P3HT cells and also a reduction in the nongeminate recombination mechanisms in both types of cells. Furthermore, we provide evidence that the reduction in nongeminate recombination in the P3HT-TiO2 devices is due in part to the passivation of deep midgap trap states in the TiO2, which prevents trap-assisted Shockley-Read-Hall recombination. Consequently a significant increase in both the open-circuit voltage and the short-circuit current was achieved, in particular for P3HT-based solar cells, where the power conversion efficiency increased by 39%.
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Affiliation(s)
- Claire L. Armstrong
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS, Cambridge, U.K.
| | - Michael B. Price
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
| | - David Muñoz-Rojas
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS, Cambridge, U.K.
- Laboratoire des Matériaux et du Génie Physique, Université Grenoble-Alpes, CNRS, 3 Parvis Louis Néel, 38016 Grenoble, France
| | | | - Mojtaba Abdi-Jalebi
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
| | - Richard H. Friend
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
| | - Neil C. Greenham
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
| | - Judith L. MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS, Cambridge, U.K.
| | - Marcus L. Böhm
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
| | - Kevin P. Musselman
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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28
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Wu H, Zhang X, Zhang Y, Yan L, Gao W, Zhang T, Wang Y, Zhao J, Yu WW. Colloidal PbSe Solar Cells with Molybdenum Oxide Modified Graphene Anodes. ACS APPLIED MATERIALS & INTERFACES 2015; 7:21082-21088. [PMID: 26355262 DOI: 10.1021/acsami.5b03894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
With good electrical conductivity, optical transparency, and mechanical compliance, graphene films have shown great potential in application for photovoltaic devices as electrodes. However, photovoltaic devices employing graphene anodes usually suffer from poor hole collection efficiency because of the mismatch of energy levels between the anode and light-harvesting layers. Here, a simple solution treatment and a low-cost solution-processed molybdenum oxide (MoOx) film were used to modify the work function of graphene and the interfacial morphology, respectively, yielding highly efficient hole transfer. As a result, the graphene/MoOx anodes demonstrated low surface roughness and high electrical conductivity. Using the graphene/MoOx anodes in PbSe nanocrystal solar cells, we achieved 1 sun power conversion efficiency of 3.56%. Compared to the control devices with indium tin oxide anodes, the graphene/MoOx-based devices show excellent performance, demonstrating the great potential of the graphene/MoOx anodes for use in optoelectronics.
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Affiliation(s)
- Hua Wu
- College of Material Science and Engineering, Qingdao University of Science and Technology , Qingdao 266042, China
| | | | | | | | | | | | | | - Jun Zhao
- Department of Chemistry and Physics, Louisiana State University , Shreveport, Louisiana 71115, United States
| | - William W Yu
- College of Material Science and Engineering, Qingdao University of Science and Technology , Qingdao 266042, China
- Department of Chemistry and Physics, Louisiana State University , Shreveport, Louisiana 71115, United States
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29
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Sadhanala A, Ahmad S, Zhao B, Giesbrecht N, Pearce PM, Deschler F, Hoye RLZ, Gödel KC, Bein T, Docampo P, Dutton SE, De Volder MFL, Friend RH. Blue-Green Color Tunable Solution Processable Organolead Chloride-Bromide Mixed Halide Perovskites for Optoelectronic Applications. NANO LETTERS 2015; 15:6095-101. [PMID: 26236949 PMCID: PMC4762541 DOI: 10.1021/acs.nanolett.5b02369] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/22/2015] [Indexed: 05/19/2023]
Abstract
Solution-processed organo-lead halide perovskites are produced with sharp, color-pure electroluminescence that can be tuned from blue to green region of visible spectrum (425-570 nm). This was accomplished by controlling the halide composition of CH3NH3Pb(BrxCl1-x)3 [0 ≤ x ≤ 1] perovskites. The bandgap and lattice parameters change monotonically with composition. The films possess remarkably sharp band edges and a clean bandgap, with a single optically active phase. These chloride-bromide perovskites can potentially be used in optoelectronic devices like solar cells and light emitting diodes (LEDs). Here we demonstrate high color-purity, tunable LEDs with narrow emission full width at half maxima (FWHM) and low turn on voltages using thin-films of these perovskite materials, including a blue CH3NH3PbCl3 perovskite LED with a narrow emission FWHM of 5 nm.
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Affiliation(s)
- Aditya Sadhanala
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
- E-mail:
| | - Shahab Ahmad
- Department of Engineering, Cambridge University, 17 Charles Babbage Road, CB3 0FS, Cambridge, United Kingdom
| | - Baodan Zhao
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Nadja Giesbrecht
- Department of Chemistry and Center for
NanoScience, Ludwig-Maximilians-Universität
München, Butenandtstraße
5-13, 81377 München, Germany
| | - Phoebe M. Pearce
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Felix Deschler
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Robert L. Z. Hoye
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Karl C. Gödel
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Thomas Bein
- Department of Chemistry and Center for
NanoScience, Ludwig-Maximilians-Universität
München, Butenandtstraße
5-13, 81377 München, Germany
| | - Pablo Docampo
- Department of Chemistry and Center for
NanoScience, Ludwig-Maximilians-Universität
München, Butenandtstraße
5-13, 81377 München, Germany
| | - Siân E. Dutton
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Michael F. L. De Volder
- Department of Engineering, Cambridge University, 17 Charles Babbage Road, CB3 0FS, Cambridge, United Kingdom
| | - Richard H. Friend
- Cavendish Laboratory, JJ Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
- E-mail:
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30
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Marshall AR, Young MR, Nozik AJ, Beard MC, Luther JM. Exploration of Metal Chloride Uptake for Improved Performance Characteristics of PbSe Quantum Dot Solar Cells. J Phys Chem Lett 2015; 6:2892-2899. [PMID: 26267176 DOI: 10.1021/acs.jpclett.5b01214] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We explored the uptake of metal chloride salts with +1 to +3 metals of Na(+), K(+), Zn(2+), Cd(2+), Sn(2+), Cu(2+), and In(3+) by PbSe QD solar cells. We also compared CdCl2 to Cd acetate and Cd nitrate treatments. PbSe QD solar cells fabricated with a CdCl2 treatment are stable for more than 270 days stored in air. We studied how temperature and immersion times affect optoelectronic properties and photovoltaic cell performance. Uptake of Cd(2+) and Zn(2+) increase open circuit voltage, whereas In(3+) and K(+) increase the photocurrent without influencing the spectral response or first exciton peak position. Using the most beneficial treatments we varied the bandgap of PbSe QD solar cells from 0.78 to 1.3 eV and find the improved VOC is more prevalent for lower bandgap QD solar cells.
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Affiliation(s)
- Ashley R Marshall
- †National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- ‡Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Matthew R Young
- †National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Arthur J Nozik
- †National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- ‡Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Matthew C Beard
- †National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Joseph M Luther
- †National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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31
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Carey GH, Abdelhady AL, Ning Z, Thon SM, Bakr OM, Sargent EH. Colloidal Quantum Dot Solar Cells. Chem Rev 2015; 115:12732-63. [DOI: 10.1021/acs.chemrev.5b00063] [Citation(s) in RCA: 844] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Graham H. Carey
- Department
of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
| | - Ahmed L. Abdelhady
- Division of Physical Sciences and Engineering, Solar & Photovoltaics Engineering Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Zhijun Ning
- School
of Physical Science and Technology, ShanghaiTech University, 100 Haike
Road, Shanghai 201210, China
| | - Susanna M. Thon
- Department
of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Osman M. Bakr
- Division of Physical Sciences and Engineering, Solar & Photovoltaics Engineering Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Edward H. Sargent
- Department
of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
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32
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Hoye RLZ, Muñoz-Rojas D, Musselman KP, Vaynzof Y, MacManus-Driscoll JL. Synthesis and modeling of uniform complex metal oxides by close-proximity atmospheric pressure chemical vapor deposition. ACS APPLIED MATERIALS & INTERFACES 2015; 7:10684-10694. [PMID: 25939729 DOI: 10.1021/am5073589] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A close-proximity atmospheric pressure chemical vapor deposition (AP-CVD) reactor is developed for synthesizing high quality multicomponent metal oxides for electronics. This combines the advantages of a mechanically controllable substrate-manifold spacing and vertical gas flows. As a result, our AP-CVD reactor can rapidly grow uniform crystalline films on a variety of substrate types at low temperatures without requiring plasma enhancements or low pressures. To demonstrate this, we take the zinc magnesium oxide (Zn(1-x)Mg(x)O) system as an example. By introducing the precursor gases vertically and uniformly to the substrate across the gas manifold, we show that films can be produced with only 3% variation in thickness over a 375 mm(2) deposition area. These thicknesses are significantly more uniform than for films from previous AP-CVD reactors. Our films are also compact, pinhole-free, and have a thickness that is linearly controllable by the number of oscillations of the substrate beneath the gas manifold. Using photoluminescence and X-ray diffraction measurements, we show that for Mg contents below 46 at. %, single phase Zn(1-x)Mg(x)O was produced. To further optimize the growth conditions, we developed a model relating the composition of a ternary oxide with the bubbling rates through the metal precursors. We fitted this model to the X-ray photoelectron spectroscopy measured compositions with an error of Δx = 0.0005. This model showed that the incorporation of Mg into ZnO can be maximized by using the maximum bubbling rate through the Mg precursor for each bubbling rate ratio. When applied to poly(3-hexylthiophene-2,5-diyl) hybrid solar cells, our films yielded an open-circuit voltage increase of over 100% by controlling the Mg content. Such films were deposited in short times (under 2 min over 4 cm(2)).
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Affiliation(s)
- Robert L Z Hoye
- †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - David Muñoz-Rojas
- †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
- ‡LMGP, University Grenoble-Alpes, CNRS, F-38000 Grenoble, France
| | - Kevin P Musselman
- †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
- §Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Yana Vaynzof
- §Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Judith L MacManus-Driscoll
- †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
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33
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Chuang CHM, Maurano A, Brandt RE, Hwang GW, Jean J, Buonassisi T, Bulović V, Bawendi MG. Open-circuit voltage deficit, radiative sub-bandgap states, and prospects in quantum dot solar cells. NANO LETTERS 2015; 15:3286-94. [PMID: 25927871 PMCID: PMC4754979 DOI: 10.1021/acs.nanolett.5b00513] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Quantum dot photovoltaics (QDPV) offer the potential for low-cost solar cells. To develop strategies for continued improvement in QDPVs, a better understanding of the factors that limit their performance is essential. Here, we study carrier recombination processes that limit the power conversion efficiency of PbS QDPVs. We demonstrate the presence of radiative sub-bandgap states and sub-bandgap state filling in operating devices by using photoluminescence (PL) and electroluminescence (EL) spectroscopy. These sub-bandgap states are most likely the origin of the high open-circuit-voltage (VOC) deficit and relatively limited carrier collection that have thus far been observed in QDPVs. Combining these results with our perspectives on recent progress in QDPV, we conclude that eliminating sub-bandgap states in PbS QD films has the potential to show a greater gain than may be attainable by optimization of interfaces between QDs and other materials. We suggest possible future directions that could guide the design of high-performance QDPVs.
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Affiliation(s)
- Chia-Hao Marcus Chuang
- Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, United States
| | - Andrea Maurano
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Riley E. Brandt
- Department of Mechanical Engineering, Massachusetts 02139, United States
| | - Gyu Weon Hwang
- Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, United States
| | - Joel Jean
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Tonio Buonassisi
- Department of Mechanical Engineering, Massachusetts 02139, United States
| | - Vladimir Bulović
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Moungi G. Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Corresponding Author:
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Chang J, Kuga Y, Mora-Seró I, Toyoda T, Ogomi Y, Hayase S, Bisquert J, Shen Q. High reduction of interfacial charge recombination in colloidal quantum dot solar cells by metal oxide surface passivation. NANOSCALE 2015; 7:5446-5456. [PMID: 25732872 DOI: 10.1039/c4nr07521h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bulk heterojunction (BHJ) solar cells based on colloidal QDs and metal oxide nanowires (NWs) possess unique and outstanding advantages in enhancing light harvesting and charge collection in comparison to planar architectures. However, the high surface area of the NW structure often brings about a large amount of recombination (especially interfacial recombination) and limits the open-circuit voltage in BHJ solar cells. This problem is solved here by passivating the surface of the metal oxide component in PbS colloidal quantum dot solar cells (CQDSCs). By coating thin TiO2 layers onto ZnO-NW surfaces, the open-circuit voltage and power conversion efficiency have been improved by over 40% in PbS CQDSCs. Characterization by transient photovoltage decay and impedance spectroscopy indicated that the interfacial recombination was significantly reduced by the surface passivation strategy. An efficiency as high as 6.13% was achieved through the passivation approach and optimization for the length of the ZnO-NW arrays (device active area: 16 mm2). All solar cells were tested in air, and exhibited excellent air storage stability (without any performance decline over more than 130 days). This work highlights the significance of metal oxide passivation in achieving high performance BHJ solar cells. The charge recombination mechanism uncovered in this work could shed light on the further improvement of PbS CQDSCs and/or other types of solar cells.
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Affiliation(s)
- Jin Chang
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
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Hoye RLZ, Chua MR, Musselman KP, Li G, Lai ML, Tan ZK, Greenham NC, MacManus-Driscoll JL, Friend RH, Credgington D. Enhanced performance in fluorene-free organometal halide perovskite light-emitting diodes using tunable, low electron affinity oxide electron injectors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:1414-9. [PMID: 25573086 PMCID: PMC4515082 DOI: 10.1002/adma.201405044] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 11/27/2014] [Indexed: 05/17/2023]
Abstract
Fluorene-free perovskite light-emitting diodes (LEDs) with low turn-on voltages, higher luminance and sharp, color-pure electroluminescence are obtained by replacing the F8 electron injector with ZnO, which is directly deposited onto the CH3NH3PbBr3 perovskite using spatial atmospheric atomic layer deposition. The electron injection barrier can also be reduced by decreasing the ZnO electron affinity through Mg incorporation, leading to lower turn-on voltages.
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Affiliation(s)
- Robert L Z Hoye
- Department of Materials Science & Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Matthew R Chua
- Department of Materials Science & Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge, CB3 0FS, UK
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Kevin P Musselman
- Department of Materials Science & Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge, CB3 0FS, UK
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Guangru Li
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - May-Ling Lai
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Zhi-Kuang Tan
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Neil C Greenham
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Judith L MacManus-Driscoll
- Department of Materials Science & Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Richard H Friend
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Dan Credgington
- Department of Physics, University of CambridgeJJ Thomson Avenue, Cambridge, CB3 0HE, UK
- E-mail:
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Su F, Lv X, Miao M. High-performance two-ply yarn supercapacitors based on carbon nanotube yarns dotted with Co3 O4 and NiO nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:854-61. [PMID: 25277293 DOI: 10.1002/smll.201401862] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/27/2014] [Indexed: 05/24/2023]
Abstract
Yarn supercapacitors are promising power sources for flexible electronic applications that require conventional fabric-like durability and wearer comfort. Carbon nanotube (CNT) yarn is an attractive choice for constructing yarn supercapacitors used in wearable textiles because of its high strength and flexibility. However, low capacitance and energy density limits the use of pure CNT yarn in wearable high-energy density devices. Here, transitional metal oxide pseudocapacitive materials NiO and Co3 O4 are deposited on as-spun CNT yarn surface using a simple electrodeposition process. The Co3 O4 deposited on the CNT yarn surface forms a uniform hybridized CNT@Co3 O4 layer. The two-ply supercapacitors formed from the CNT@Co3 O4 composite yarns display excellent electrochemical properties with very high capacitance of 52.6 mF cm(-2) and energy density of 1.10 μWh cm(-2) . The high performance two-ply CNT@Co3 O4 yarn supercapacitors are mechanically and electrochemically robust to meet the high performance requirements of power sources for wearable electronics.
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Affiliation(s)
- Fenghua Su
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
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Zhang X, Zhang Y, Yan L, Wu H, Gao W, Zhao J, Yu WW. PbSe nanocrystal solar cells using bandgap engineering. RSC Adv 2015. [DOI: 10.1039/c5ra10715f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A 12.8% improvement in power conversion efficiency of PbSe nanocrystal-based solar cells was achieved using bandgap engineering.
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Affiliation(s)
- Xiaoyu Zhang
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Yu Zhang
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Long Yan
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Hua Wu
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
| | - Wenzhu Gao
- State Key Laboratory of Superhard Materials
- College of Physics
- Jilin University
- Changchun 130012
- China
| | - Jun Zhao
- College of Material Science and Engineering
- Qingdao University of Science and Technology
- Qingdao 266042
- China
- Department of Chemistry and Physics
| | - William W. Yu
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- China
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Hoye RZ, Heffernan S, Ievskaya Y, Sadhanala A, Flewitt A, Friend RH, MacManus-Driscoll JL, Musselman KP. Engineering Schottky contacts in open-air fabricated heterojunction solar cells to enable high performance and ohmic charge transport. ACS APPLIED MATERIALS & INTERFACES 2014; 6:22192-22198. [PMID: 25418326 PMCID: PMC4333600 DOI: 10.1021/am5058663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 11/24/2014] [Indexed: 05/31/2023]
Abstract
The efficiencies of open-air processed Cu2O/Zn(1-x)Mg(x)O heterojunction solar cells are doubled by reducing the effect of the Schottky barrier between Zn(1-x)Mg(x)O and the indium tin oxide (ITO) top contact. By depositing Zn(1-x)Mg(x)O with a long band-tail, charge flows through the Zn(1-x)Mg(x)O/ITO Schottky barrier without rectification by hopping between the sub-bandgap states. High current densities are obtained by controlling the Zn(1-x)Mg(x)O thickness to ensure that the Schottky barrier is spatially removed from the p-n junction, allowing the full built-in potential to form, in addition to taking advantage of the increased electrical conductivity of the Zn(1-x)Mg(x)O films with increasing thickness. This work therefore shows that the Zn(1-x)Mg(x)O window layer sub-bandgap state density and thickness are critical parameters that can be engineered to minimize the effect of Schottky barriers on device performance. More generally, these findings show how to improve the performance of other photovoltaic system reliant on transparent top contacts, e.g., CZTS and CIGS.
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Affiliation(s)
- Robert
L. Z. Hoye
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Shane Heffernan
- Electrical
Engineering Division, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Yulia Ievskaya
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Aditya Sadhanala
- Department
of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Andrew Flewitt
- Electrical
Engineering Division, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Richard H. Friend
- Department
of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Judith L. MacManus-Driscoll
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Kevin P. Musselman
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
- Department
of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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