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Pruksawan S, Lin Z, Lee YL, Chee HL, Wang F. 4D-Printed Hydrogel Actuators through Diffusion-Path Architecture Design. ACS Appl Mater Interfaces 2023; 15:46388-46399. [PMID: 37738306 DOI: 10.1021/acsami.3c10112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Recently, smart hydrogels have garnered considerable attention as biomedical devices, and several approaches have been introduced for their fabrication, including the incorporation of stimulus-responsive additives, utilization of molecular imprinting techniques, and application of multilayered hydrogels. However, the nonuniform properties resulting from these approaches limit the practical applications of hydrogels by causing inconsistent performance and behavior. In this study, we propose a novel approach to manipulating the swelling kinetics of hydrogels by engineering their diffusion-path architecture. By simply adjusting the diffusion path length within the hydrogel, we achieved a significant change in swelling kinetics. This approach enables precise control over the diffusion and transport processes within the hydrogel, resulting in enhanced swelling kinetics when reducing the diffusion path length. Furthermore, by strategically designing the diffusion-path architecture of a 3D-printed hydrogel specimen, we can fabricate smart hydrogel actuators that exhibit reversible shape transformations during swelling and deswelling through a nonequilibrium differential swelling. The proposed approach eliminates the need to modify the spatial properties of hydrogel structures such as cross-linking density, polymer, or additive compositions, thereby achieving uniform properties throughout the hydrogel and creating new possibilities for the development of advanced 4D-printed biomedical devices.
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Affiliation(s)
- Sirawit Pruksawan
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Zehuang Lin
- Department of Materials Science and Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, Singapore 117575, Republic of Singapore
| | - Yock Leng Lee
- Department of Biomedical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583, Republic of Singapore
| | - Heng Li Chee
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - FuKe Wang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
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2
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Segura-Sanchis E, García-Aboal R, Fenollosa R, Ramiro-Manzano F, Atienzar P. Scanning Photocurrent Microscopy in Single Crystal Multidimensional Hybrid Lead Bromide Perovskites. Nanomaterials (Basel) 2023; 13:2570. [PMID: 37764599 PMCID: PMC10535732 DOI: 10.3390/nano13182570] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/08/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023]
Abstract
We investigated solution-grown single crystals of multidimensional 2D-3D hybrid lead bromide perovskites using spatially resolved photocurrent and photoluminescence. Scanning photocurrent microscopy (SPCM) measurements where the electrodes consisted of a dip probe contact and a back contact. The crystals revealed significant differences between 3D and multidimensional 2D-3D perovskites under biased detection, not only in terms of photocarrier decay length values but also in the spatial dynamics across the crystal. In general, the photocurrent maps indicate that the closer the border proximity, the shorter the effective decay length, thus suggesting a determinant role of the border recombination centers in monocrystalline samples. In this case, multidimensional 2D-3D perovskites exhibited a simple fitting model consisting of a single exponential, while 3D perovskites demonstrated two distinct charge carrier migration dynamics within the crystal: fast and slow. Although the first one matches that of the 2D-3D perovskite, the long decay of the 3D sample exhibits a value two orders of magnitude larger. This difference could be attributed to the presence of interlayer screening and a larger exciton binding energy of the multidimensional 2D-3D perovskites with respect to their 3D counterparts.
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Affiliation(s)
| | | | | | - Fernando Ramiro-Manzano
- Instituto de Tecnología Química, Consejo Superior de Investigaciones Científicas, Universitat Politècnica de València, Avenida de los Naranjos s/n, 46022 Valencia, Spain; (E.S.-S.); (R.G.-A.); (R.F.)
| | - Pedro Atienzar
- Instituto de Tecnología Química, Consejo Superior de Investigaciones Científicas, Universitat Politècnica de València, Avenida de los Naranjos s/n, 46022 Valencia, Spain; (E.S.-S.); (R.G.-A.); (R.F.)
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3
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John P, Gómez Ruiz M, van Deurzen L, Lähnemann J, Trampert A, Geelhaar L, Brandt O, Auzelle T. Growth kinetics and substrate stability during high-temperature molecular beam epitaxy of AlN nanowires. Nanotechnology 2023; 34. [PMID: 37579739 DOI: 10.1088/1361-6528/acefd8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/13/2023] [Indexed: 08/16/2023]
Abstract
We study the molecular beam epitaxy of AlN nanowires between 950 °C and 1215 °C, well above the usual growth temperatures, to identify optimal growth conditions. The nanowires are grown by self-assembly on TiN(111) films sputtered onto Al2O3. Above 1100 °C, the TiN film is seen to undergo grain growth and its surface exhibits {111} facets where AlN nucleation preferentially occurs. Modeling of the nanowire elongation rate measured at different temperatures shows that the Al adatom diffusion length maximizes at 1150 °C, which appears to be the optimum growth temperature. However, analysis of the nanowire luminescence shows a steep increase in the deep-level signal already above 1050 °C, associated with O incorporation from the Al2O3substrate. Comparison with AlN nanowires grown on Si, MgO and SiC substrates suggests that heavy doping of Si and O by interdiffusion from the TiN/substrate interface increases the nanowire internal quantum efficiency, presumably due to the formation of a SiNxor AlOxpassivation shell. The outdiffusion of Si and O would also cause the formation of the inversion domains observed in the nanowires. It follows that for optoelectronic and piezoelectric applications, optimal AlN nanowire ensembles should be prepared at 1150 °C on TiN/SiC substrates and will require anex situsurface passivation.
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Affiliation(s)
- P John
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - M Gómez Ruiz
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L van Deurzen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, United States of America
| | - J Lähnemann
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - A Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - O Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - T Auzelle
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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4
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Caporale AS, Nezzo M, Di Trani MG, Maiuro A, Miano R, Bove P, Mauriello A, Manenti G, Capuani S. Acquisition Parameters Influence Diffusion Metrics Effectiveness in Probing Prostate Tumor and Age-Related Microstructure. J Pers Med 2023; 13:jpm13050860. [PMID: 37241031 DOI: 10.3390/jpm13050860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/18/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
This study aimed to investigate the Diffusion-Tensor-Imaging (DTI) potential in the detection of microstructural changes in prostate cancer (PCa) in relation to the diffusion weight (b-value) and the associated diffusion length lD. Thirty-two patients (age range = 50-87 years) with biopsy-proven PCa underwent Diffusion-Weighted-Imaging (DWI) at 3T, using single non-zero b-value or groups of b-values up to b = 2500 s/mm2. The DTI maps (mean-diffusivity, MD; fractional-anisotropy, FA; axial and radial diffusivity, D// and D┴), visual quality, and the association between DTI-metrics and Gleason Score (GS) and DTI-metrics and age were discussed in relation to diffusion compartments probed by water molecules at different b-values. DTI-metrics differentiated benign from PCa tissue (p ≤ 0.0005), with the best discriminative power versus GS at b-values ≥ 1500 s/mm2, and for b-values range 0-2000 s/mm2, when the lD is comparable to the size of the epithelial compartment. The strongest linear correlations between MD, D//, D┴, and GS were found at b = 2000 s/mm2 and for the range 0-2000 s/mm2. A positive correlation between DTI parameters and age was found in benign tissue. In conclusion, the use of the b-value range 0-2000 s/mm2 and b-value = 2000 s/mm2 improves the contrast and discriminative power of DTI with respect to PCa. The sensitivity of DTI parameters to age-related microstructural changes is worth consideration.
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Affiliation(s)
- Alessandra Stella Caporale
- Department of Neuroscience, Imaging and Clinical Sciences, 'G. d'Annunzio' University of Chieti-Pescara, 66100 Chieti, Italy
- Institute for Advanced Biomedical Technologies (ITAB), 'G. d'Annunzio' University of Chieti-Pescara, 66100 Chieti, Italy
| | - Marco Nezzo
- Interventional Radiology Unit, Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Maria Giovanna Di Trani
- Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, 00184 Rome, Italy
| | - Alessandra Maiuro
- CNR ISC, c/o Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Roberto Miano
- Division of Urology, Department of Surgical Sciences, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Pierluigi Bove
- Division of Urology, Department of Surgical Sciences, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Alessandro Mauriello
- Anatomic Pathology, Department of Experimental Medicine, PTV Foundation, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Guglielmo Manenti
- Department of Biomedicine and Prevention, UOC Radiology PTV Foundation, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Silvia Capuani
- CNR ISC, c/o Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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5
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Turedi B, Lintangpradipto MN, Sandberg OJ, Yazmaciyan A, Matt GJ, Alsalloum AY, Almasabi K, Sakhatskyi K, Yakunin S, Zheng X, Naphade R, Nematulloev S, Yeddu V, Baran D, Armin A, Saidaminov MI, Kovalenko MV, Mohammed OF, Bakr OM. Single-Crystal Perovskite Solar Cells Exhibit Close to Half A Millimeter Electron- Diffusion Length. Adv Mater 2022; 34:e2202390. [PMID: 36069995 DOI: 10.1002/adma.202202390] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Single-crystal halide perovskites exhibit photogenerated-carriers of high mobility and long lifetime, making them excellent candidates for applications demanding thick semiconductors, such as ionizing radiation detectors, nuclear batteries, and concentrated photovoltaics. However, charge collection depreciates with increasing thickness; therefore, tens to hundreds of volts of external bias is required to extract charges from a thick perovskite layer, leading to a considerable amount of dark current and fast degradation of perovskite absorbers. However, extending the carrier-diffusion length can mitigate many of the anticipated issues preventing the practical utilization of perovskites in the abovementioned applications. Here, single-crystal perovskite solar cells that are up to 400 times thicker than state-of-the-art perovskite polycrystalline films are fabricated, yet retain high charge-collection efficiency in the absence of an external bias. Cells with thicknesses of 110, 214, and 290 µm display power conversion efficiencies (PCEs) of 20.0, 18.4, and 14.7%, respectively. The remarkable persistence of high PCEs, despite the increase in thickness, is a result of a long electron-diffusion length in those cells, which was estimated, from the thickness-dependent short-circuit current, to be ≈0.45 mm under 1 sun illumination. These results pave the way for adapting perovskite devices to optoelectronic applications in which a thick active layer is essential.
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Affiliation(s)
- Bekir Turedi
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Muhammad N Lintangpradipto
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Oskar J Sandberg
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Aren Yazmaciyan
- KAUST Solar Center (KSC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Gebhard J Matt
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Abdullah Y Alsalloum
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Khulud Almasabi
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Kostiantyn Sakhatskyi
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Sergii Yakunin
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Xiaopeng Zheng
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Rounak Naphade
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Saidkhodzha Nematulloev
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Vishal Yeddu
- Department of Chemistry and Department of Electrical & Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Derya Baran
- KAUST Solar Center (KSC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Makhsud I Saidaminov
- Department of Chemistry and Department of Electrical & Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Maksym V Kovalenko
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Omar F Mohammed
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Advanced Membranes and Porous Materials Center (AMPM), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Osman M Bakr
- KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
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Zohar A, Kulbak M, Turren-Cruz SH, Nayak PK, Kama A, Hagfeldt A, Snaith HJ, Hodes G, Cahen D. In Operando, Photovoltaic, and Microscopic Evaluation of Recombination Centers in Halide Perovskite-Based Solar Cells. ACS Appl Mater Interfaces 2022; 14:34171-34179. [PMID: 34460226 DOI: 10.1021/acsami.1c08675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The origin of the low densities of electrically active defects in Pb halide perovskite (HaP), a crucial factor for their use in photovoltaics, light emission, and radiation detection, remains a matter of discussion, in part because of the difficulty in determining these densities. Here, we present a powerful approach to assess the defect densities, based on electric field mapping in working HaP-based solar cells. The minority carrier diffusion lengths were deduced from the electric field profile, measured by electron beam-induced current (EBIC). The EBIC method was used earlier to get the first direct evidence for the n-i-p junction structure, at the heart of efficient HaP-based PV cells, and later by us and others for further HaP studies. This manuscript includes EBIC results on illuminated cell cross sections (in operando) at several light intensities to compare optoelectronic characteristics of different cells made by different groups in several laboratories. We then apply a simple, effective single-level defect model that allows deriving the densities (Nr) of the defect acting as recombination center. We find Nr ≈ 1 × 1013 cm-3 for mixed A cation lead bromide-based HaP films and ∼1 × 1014 cm-3 for MAPbBr3(Cl). As EBIC photocurrents are similar at the grain bulk and boundaries, we suggest that the defects are at the interfaces with selective contacts rather than in the HaP film. These results are relevant for photovoltaic devices as the EBIC responses distinguish clearly between high- and low-efficiency devices. The most efficient devices have n-i-p structures with a close-to-intrinsic HaP film, and the selective contacts then dictate the electric field strength throughout the HaP absorber.
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Affiliation(s)
- Arava Zohar
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael Kulbak
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Silver H Turren-Cruz
- École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Institute of Advanced Materials (INAM), Jaume I University, Castelló de la Plana 12071, Spain
| | - Pabitra K Nayak
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad 500046, India
| | - Adi Kama
- Chemistry Department and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Anders Hagfeldt
- École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Henry J Snaith
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Gary Hodes
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Cahen
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
- Chemistry Department and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
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7
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Lahreche A, Babichev AV, Beggah Y, Tchernycheva M. Modeling of the electron beam induced current signal in nanowires with an axial p-n junction. Nanotechnology 2022; 33:395701. [PMID: 35700698 DOI: 10.1088/1361-6528/ac7887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
A tridimensional mathematical model to calculate the electron beam induced current (EBIC) of an axial p-n nanowire junction is proposed. The effect of the electron beam and junction parameters on the distribution of charge carriers and on the collected EBIC current is reported. We demonstrate that the diffusion of charge carriers within the wire is strongly influenced by the electrical state of its lateral surface which is characterized by a parameter called surface recombination velocity (vr). When the surface recombination is weak (i.e. lowvrvalue), the diffusion of charge carriers occurs in one dimension (1D) along the wire axis, and, in this case, the use of bulk EBIC models to extract the diffusion length (L) of charge carriers is justified. However, when the surface effects are strong (i.e. highvrvalues), the diffusion happens in three dimensions (3D). In this case, the EBIC profiles depend onvrvalue and two distinct cases can be defined. If theLis larger than the nanowire radius (ra), the EBIC profiles show a strong dependency with this parameter. This gives evidence that the recombination of generated carriers on the surface throughvris the dominant process. In this situation, a decrease of two orders of magnitude in the EBIC profiles computed with a high and a lowvrvalue is observed in neutral regions of the junction. For the case ofLsmaller thanrathe dependency of the EBIC profiles on thevris weak, and the prevalent recombination mechanism is the bulk recombination process.
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Affiliation(s)
- Abderrezak Lahreche
- Department de technologie, Université A.Mira de Bejaia, 6000 Bejaia, Algérie
- Laboratoire Matériaux: Elaborations-Propriétés - Applications (LMEPA), Université Jijel, 18000 Jijel, Algérie
| | - Andrey V Babichev
- Saint Petersburg Electrotechnical University "LETI", 197376 St. Petersburg, Russia
- ITMO University, 197101 St. Petersburg, Russia
| | - Yamina Beggah
- Laboratoire Matériaux: Elaborations-Propriétés - Applications (LMEPA), Université Jijel, 18000 Jijel, Algérie
| | - Maria Tchernycheva
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, University Paris-Saclay, F-91120 Palaiseau, France
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8
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Dutta R, Pradhan A, Mondal P, Kakkar S, Sai TP, Ghosh A, Basu JK. Enhancing Carrier Diffusion Length and Quantum Efficiency through Photoinduced Charge Transfer in Layered Graphene-Semiconducting Quantum Dot Devices. ACS Appl Mater Interfaces 2021; 13:24295-24303. [PMID: 33998798 DOI: 10.1021/acsami.1c04254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hybrid devices consisting of graphene or transition metal dichalcogenides (TMDs) and semiconductor quantum dots (QDs) were widely studied for potential photodetector and photovoltaic applications, while for photodetector applications, high internal quantum efficiency (IQE) is required for photovoltaic applications and enhanced carrier diffusion length is also desirable. Here, we reported the electrical measurements on hybrid field-effect optoelectronic devices consisting of compact QD monolayer at controlled separations from single-layer graphene, and the structure is characterized by high IQE and large enhancement of minority carrier diffusion length. While the IQE ranges from 10.2% to 18.2% depending on QD-graphene separation, ds, the carrier diffusion length, LD, estimated from scanning photocurrent microscopy (SPCM) measurements, could be enhanced by a factor of 5-8 as compared to that of pristine graphene. IQE and LD could be tuned by varying back gate voltage and controlling the extent of charge separation from the proximal QD layer due to photoexcitation. The obtained IQE values were remarkably high, considering that only a single QD layer was used, and the parameters could be further enhanced in such devices significantly by stacking multiple layers of QDs. Our results could have significant implications for utilizing these hybrid devices as photodetectors and active photovoltaic materials with high efficiency.
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Affiliation(s)
- Riya Dutta
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Avradip Pradhan
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Praloy Mondal
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Saloni Kakkar
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - T Phanindra Sai
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Arindam Ghosh
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Jaydeep Kumar Basu
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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9
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Zhou C, Chen W, Yang S, Ou Q, Gan Z, Bao Q, Jia B, Wen X. Determining In-Plane Carrier Diffusion in Two-Dimensional Perovskite Using Local Time-Resolved Photoluminescence. ACS Appl Mater Interfaces 2020; 12:26384-26390. [PMID: 32400152 DOI: 10.1021/acsami.0c05539] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The diffusion length of photogenerated carriers is a crucial parameter in semiconductors for optoelectronic applications. However, it is a challenging task to determine the diffusion length in layered nanoplatelets due to their anisotropic diffusion of photogenerated carriers and nanometer-thin thickness. Here, we demonstrate a novel method to determine the in-plane diffusion length of photogenerated carriers in layered nanoplatelets using local time-resolved photoluminescence. Also, the in-plane carrier diffusion length of 1.82 μm is obtained for an exfoliated (BA)2PbI4 (BA = CH3(CH2)3NH3) perovskite nanoplatelet. This method is particularly useful for weak luminescent materials and the materials that are easily damaged by long-term laser beam because of the high detection sensitivity. This technique is extendable to other layered materials and therefore plays a valuable role in the development and optimization of two-dimensional (2D) and three-dimensional (3D) semiconductor materials and devices for photovoltaic and photonic applications.
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Affiliation(s)
- Chunhua Zhou
- Centre for Translational Atomaterials, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, Melbourne, Victoria 3122, Australia
| | - Weijian Chen
- Centre for Translational Atomaterials, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, Melbourne, Victoria 3122, Australia
| | - Shuang Yang
- School of Materials Science and Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Qingdong Ou
- Department of Materials Science and Engineering, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Scenic Blvd & Wellington Road, Clayton, Victoria 3800, Australia
| | - Zhixing Gan
- Key Laboratory of Optoelectronic Technology of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Qiaoliang Bao
- Department of Materials Science and Engineering, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Scenic Blvd & Wellington Road, Clayton, Victoria 3800, Australia
| | - Baohua Jia
- Centre for Translational Atomaterials, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, Melbourne, Victoria 3122, Australia
| | - Xiaoming Wen
- Centre for Translational Atomaterials, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, Melbourne, Victoria 3122, Australia
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10
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Kim DK, Choi D, Park M, Jeong KS, Choi JH. Cesium Lead Bromide Quantum Dot Light-Emitting Field-Effect Transistors. ACS Appl Mater Interfaces 2020; 12:21944-21951. [PMID: 32319744 DOI: 10.1021/acsami.0c06904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solution-processable perovskite quantum dots are considered as promising optical materials for light-emitting optoelectronics. Light-emitting field-effect transistors (LEFETs) that can be operated under a relatively lower potential with a high energy conversion efficiency are yet to be realized with perovskite quantum dots. Here, we present the CsPbBr3 quantum dot-based LEFET. Surprisingly, unipolar transport characteristics with strong electroluminescence were observed at the interface of the CsPbBr3 QD-LEFET along with an exceptionally wide recombination zone of 80 μm, an order of magnitude larger than that of organic/polymer LEFETs. Based on the systematic analysis for the electroluminescence of the CsPbBr3 NC-LEFET, we revealed that the increased diffusion length determined by the majority carrier mobility and the lifetime well explains the remarkably wide recombination zone. Furthermore, it was found that the energy-level matching and transport geometry of the heterostructure also determine the charge distribution and recombination, substantially affecting the performance of the CsPbBr3 QD LEFET.
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Affiliation(s)
- Dae-Kyu Kim
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, Republic of Korea
| | - Dongsun Choi
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, Republic of Korea
| | - Mihyeon Park
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, Republic of Korea
| | - Kwang Seob Jeong
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, Republic of Korea
| | - Jong-Ho Choi
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, Republic of Korea
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11
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Singh J, Jadhav S, Avasthi S, Sen P. Designing Photocatalytic Nanostructured Antibacterial Surfaces: Why Is Black Silica Better than Black Silicon? ACS Appl Mater Interfaces 2020; 12:20202-20213. [PMID: 32283016 DOI: 10.1021/acsami.0c02854] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The efficiency of photocatalytic antibacterial surfaces is limited by the absorption of light in it. Light absorption in photocatalytic surfaces can be enhanced by structuring it, leading to increased generation of reactive oxygen species (ROS) and hence improved bactericidal efficacy. A second, more passive methodology to kill bacteria involves the use of sharp nanostructures that mechanically disrupt the bacterial membrane. Recently, these two mechanisms were combined to form photoactive nanostructured surfaces with better antibacterial efficacy. However, the design rules for fabricating the optimal photoactive nanostructured surfaces have not been articulated. Here we show that for optimal performance it is very important to account for optoelectrical properties and geometry of the photoactive coating and the underlying pillar. We show that TiO2-coated nanopillars arrays made of SiO2, a material with a low extinction coefficient, have 73% higher bactericidal efficacies than those made of Si, a material with a high extinction coefficient. The finite element method (FEM) shows that despite the higher absorption in higher aspect ratio nanopillars, their performance is not always better. The concentration of bulk ROS saturates around 5 μm. For taller pillars, the improvement in surface ROS concentration is minimal due to the diffusion bottleneck. Simulation results corroborate with the experimentally observed methylene blue degradation and bacterial count measurements and provide an explanation of the observed phenomenon. The guidelines for designing these optically activated photocatalyst nanopillars can be extended to other photocatalytic material after adjusting for their respective properties.
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Affiliation(s)
- Jagriti Singh
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Shubham Jadhav
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sushobhan Avasthi
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Prosenjit Sen
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
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12
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Yang J, Lee J, Lee J, Yi W. Improving Charge Collection from Colloidal Quantum Dot Photovoltaics by Single-Walled Carbon Nanotube Incorporation. ACS Appl Mater Interfaces 2019; 11:33759-33769. [PMID: 31430430 DOI: 10.1021/acsami.9b07089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Improving charge collection is one of the key issues for high-performance PbS colloidal quantum dot photovoltaics (CQDPVs) due to the considerable charge loss resulting from the low mobility and large defect densities of the 1,2-ethanedithiol-treated PbS quantum dot hole-transporting layer (HTL). To overcome these limitations, single-walled carbon nanotubes (SWNTs) and C60-encapsulated SWNTs (C60@SWNTs) are incorporated into the HTL in CQDPVs. SWNT-incorporated CQDPV demonstrates a significantly improved short-circuit current density (JSC), and C60@SWNT-incorporated CQDPV exhibits an even higher JSC than that of pristine SWNT. Both result in improved power-conversion efficiencies. Hole-selective, photoinduced charge extraction with linearly increasing voltage measurements demonstrates that SWNT or C60@SWNT incorporation improves hole-transporting behavior, rendering suppressed charge recombination and enhanced mobility of the HTL. The enhanced p-type characteristics and the improved hole diffusion lengths of SWNT- or C60@SWNT-incorporated HTL bring improvement of the entire hole-transporting length and enable lossless hole collection, which results in the JSC enhancement of the CQDPVs.
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Affiliation(s)
- Jonghee Yang
- Research Institute for Natural Sciences and Department of Chemistry , Hanyang University , Seoul 04763 , Republic of Korea
| | - Jongtaek Lee
- Research Institute for Natural Sciences and Department of Chemistry , Hanyang University , Seoul 04763 , Republic of Korea
| | - Junyoung Lee
- Research Institute for Natural Sciences and Department of Chemistry , Hanyang University , Seoul 04763 , Republic of Korea
| | - Whikun Yi
- Research Institute for Natural Sciences and Department of Chemistry , Hanyang University , Seoul 04763 , Republic of Korea
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13
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Li P, Zhang Y, Liang C, Xing G, Liu X, Li F, Liu X, Hu X, Shao G, Song Y. Phase Pure 2D Perovskite for High-Performance 2D-3D Heterostructured Perovskite Solar Cells. Adv Mater 2018; 30:e1805323. [PMID: 30387210 DOI: 10.1002/adma.201805323] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/14/2018] [Indexed: 06/08/2023]
Abstract
Three-dimensional (3D) metal-halide perovskite solar cells (PSCs) have demonstrated exceptional high efficiency. However, instability of the 3D perovskite is the main challenge for industrialization. Incorporation of some long organic cations into perovskite crystal to terminate the lattice, and function as moisture and oxygen passivation layer and ion migration blocking layer, is proven to be an effective method to enhance the perovskite stability. Unfortunately, this method typically sacrifices charge-carrier extraction efficiency of the perovskites. Even in 2D-3D vertically aligned heterostructures, a spread of bandgaps in the 2D due to varying degrees of quantum confinement also results in charge-carrier localization and carrier mobility reduction. A trade-off between the power conversion efficiency and stability is made. Here, by introducing 2D C6 H18 N2 O2 PbI4 (EDBEPbI4 ) microcrystals into the precursor solution, the grain boundaries of the deposited 3D perovskite film are vertically passivated with phase pure 2D perovskite. The phases pure (inorganic layer number n = 1) 2D perovskite can minimize photogenerated charge-carrier localization in the low-dimensional perovskite. The dominant vertical alignment does not affect charge-carrier extraction. Therefore, high-efficiency (21.06%) and ultrastable (retain 90% of the initial efficiency after 3000 h in air) planar PSCs are demonstrated with these 2D-3D mixtures.
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Affiliation(s)
- Pengwei Li
- Key Laboratory of Green Printing CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yiqiang Zhang
- State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, ZhengZhou University, ZhengZhou, 450001, P. R. China
| | - Chao Liang
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau, 999078, P. R. China
| | - Guichuan Xing
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau, 999078, P. R. China
| | - Xiaolong Liu
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Fengyu Li
- Key Laboratory of Green Printing CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
| | - Xiaotao Liu
- State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, ZhengZhou University, ZhengZhou, 450001, P. R. China
| | - Xiaotian Hu
- Key Laboratory of Green Printing CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Guosheng Shao
- State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, ZhengZhou University, ZhengZhou, 450001, P. R. China
| | - Yanlin Song
- Key Laboratory of Green Printing CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
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14
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Adhyaksa GWP, Brittman S, Āboliņš H, Lof A, Li X, Keelor JD, Luo Y, Duevski T, Heeren RMA, Ellis SR, Fenning DP, Garnett EC. Understanding Detrimental and Beneficial Grain Boundary Effects in Halide Perovskites. Adv Mater 2018; 30:e1804792. [PMID: 30368936 DOI: 10.1002/adma.201804792] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Grain boundaries play a key role in the performance of thin-film optoelectronic devices and yet their effect in halide perovskite materials is still not understood. The biggest factor limiting progress is the inability to identify grain boundaries. Noncrystallographic techniques can misidentify grain boundaries, leading to conflicting literature reports about their influence; however, the gold standard - electron backscatter diffraction (EBSD) - destroys halide perovskite thin films. Here, this problem is solved by using a solid-state EBSD detector with 6000 times higher sensitivity than the traditional phosphor screen and camera. Correlating true grain size with photoluminescence lifetime, carrier diffusion length, and mobility shows that grain boundaries are not benign but have a recombination velocity of 1670 cm s-1 , comparable to that of crystalline silicon. Amorphous grain boundaries are also observed that give rise to locally brighter photoluminescence intensity and longer lifetimes. This anomalous grain boundary character offers a possible explanation for the mysteriously long lifetime and record efficiency achieved in small grain halide perovskite thin films. It also suggests a new approach for passivating grain boundaries, independent of surface passivation, to lead to even better performance in optoelectronic devices.
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Affiliation(s)
- Gede W P Adhyaksa
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
| | - Sarah Brittman
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
| | - Haralds Āboliņš
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
| | - Andries Lof
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
| | - Xueying Li
- Department of Nanoengineering, University of California San Diego, CA, 92093, USA
| | - Joel D Keelor
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, 6229, ER, Maastricht, The Netherlands
| | - Yanqi Luo
- Department of Nanoengineering, University of California San Diego, CA, 92093, USA
| | - Teodor Duevski
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
| | - Ron M A Heeren
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, 6229, ER, Maastricht, The Netherlands
| | - Shane R Ellis
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, 6229, ER, Maastricht, The Netherlands
| | - David P Fenning
- Department of Nanoengineering, University of California San Diego, CA, 92093, USA
| | - Erik C Garnett
- Center for Nanophotonics, AMOLF, Science Park 104, 1098, XG, Amsterdam, The Netherlands
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15
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Kim YC, Nguyen VT, Lee S, Park JY, Ahn YH. Evaluation of Transport Parameters in MoS 2/Graphene Junction Devices Fabricated by Chemical Vapor Deposition. ACS Appl Mater Interfaces 2018; 10:5771-5778. [PMID: 29355012 DOI: 10.1021/acsami.7b16177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrated imaging of the depletion layer in a MoS2/graphene heterojunction fabricated by chemical vapor deposition and obtained their transport parameters such as diffusion length, lifetime, and mobility by using scanning photocurrent microscopy (SPCM). The device exhibited a n-type operation, which was determined by the MoS2 layer with a lower mobility. The SPCM revealed the presence of the depletion layer at the heterojunction, whereas graphene provided an excellent electrical contact for the MoS2 layer without resulting in a rectifying behavior, even if they were anchored within a very short range. The polarity of the photocurrent signal switched when we applied a drain-source bias voltage, from which we extracted the potential barrier at the junction. More importantly, a bias-dependent SPCM allowed us to simultaneously record the diffusion lengths of both majority and minority carriers for the respective MoS2 and graphene layers. By combining the diffusion lengths with the lifetimes measured by femtosecond SPCM, we determined the electron and hole mobilities in each layer, from which we found that the electron mobility (160 cm2 V-1 s-1) was higher than the hole mobility (80 cm2 V-1 s-1) in MoS2, whereas the hole mobility (15 000 cm2 V-1 s-1) was relatively higher in graphene.
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Affiliation(s)
- Young Chul Kim
- Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 16499, Korea
| | - Van Tu Nguyen
- Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 16499, Korea
| | - Soonil Lee
- Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 16499, Korea
| | - Ji-Yong Park
- Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 16499, Korea
| | - Yeong Hwan Ahn
- Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 16499, Korea
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16
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Shargaieva O, Lang F, Rappich J, Dittrich T, Klaus M, Meixner M, Genzel C, Nickel NH. Influence of the Grain Size on the Properties of CH 3NH 3PbI 3 Thin Films. ACS Appl Mater Interfaces 2017; 9:38428-38435. [PMID: 29039197 DOI: 10.1021/acsami.7b10056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hybrid perovskites have already shown a huge success as an absorber in solar cells, resulting in the skyrocketing rise in the power conversion efficiency to more than η = 22%. Recently, it has been established that the crystal quality is one of the most important parameters to obtain devices with high efficiencies. However, the influence of the crystal quality on the material properties is not fully understood. Here, the influence of the morphology on electronic properties of CH3NH3PbI3 thin films is investigated. Postannealing was used to vary the average grain size continuously from ≈150 to ≈1000 nm. Secondary grain growth is thermally activated with an activation energy of Ea = 0.16 eV. The increase in the grain size leads to an enhancement of the photoluminescence, indicating an improvement in the material quality. According to surface photovoltage measurements, the charge-carrier transport length exhibits a linear increase with increasing grain size. The charge-carrier diffusion length is limited by grain boundaries. Moreover, an improved morphology leads to a drastic increase in power conversion efficiency of the devices.
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Affiliation(s)
- Oleksandra Shargaieva
- Institute Silicon Photovoltaics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Kekuléstr. 5, 12489 Berlin, Germany
| | - Felix Lang
- Institute Silicon Photovoltaics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Kekuléstr. 5, 12489 Berlin, Germany
| | - Jörg Rappich
- Institute Silicon Photovoltaics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Kekuléstr. 5, 12489 Berlin, Germany
| | - Thomas Dittrich
- Institute Silicon Photovoltaics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Kekuléstr. 5, 12489 Berlin, Germany
| | - Manuela Klaus
- Department of Microstructure and Residual Stress Analysis, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Matthias Meixner
- Department of Microstructure and Residual Stress Analysis, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Christoph Genzel
- Department of Microstructure and Residual Stress Analysis, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Norbert H Nickel
- Institute Silicon Photovoltaics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Kekuléstr. 5, 12489 Berlin, Germany
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17
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Abstract
Lead sulfide quantum dots (PbS QDs) are an attractive material system for the development of low-cost photovoltaics (PV) due to their ease of processing and stability in air, with certified power conversion efficiencies exceeding 11%. However, even the best PbS QD PV devices are limited by diffusive transport, as the optical absorption length exceeds the minority carrier diffusion length. Understanding minority carrier transport in these devices will therefore be critical for future efficiency improvement. We utilize cross-sectional electron beam-induced current (EBIC) microscopy and develop methodology to quantify minority carrier diffusion length in PbS QD PV devices. We show that holes are the minority carriers in tetrabutylammonium iodide (TBAI)-treated PbS QD films due to the formation of a p-n junction with an ethanedithiol (EDT)-treated QD layer, whereas a heterojunction with n-type ZnO forms a weaker n+-n junction. This indicates that modifying the standard device architecture to include a p-type window layer would further boost the performance of PbS QD PV devices. Furthermore, quantitative EBIC measurements yield a lower bound of 110 nm for the hole diffusion length in TBAI-treated PbS QD films, which informs design rules for planar and ordered bulk heterojunction PV devices. Finally, the low-energy EBIC approach developed in our work is generally applicable to other emerging thin-film PV absorber materials with nanoscale diffusion lengths.
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Affiliation(s)
- Paul H Rekemeyer
- Department of Materials Science and Engineering and ‡Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02141, United States
| | - Chia-Hao M Chuang
- Department of Materials Science and Engineering and ‡Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02141, United States
| | - Moungi G Bawendi
- Department of Materials Science and Engineering and ‡Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02141, United States
| | - Silvija Gradečak
- Department of Materials Science and Engineering and ‡Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02141, United States
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18
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Koleilat GI, Vosgueritchian M, Lei T, Zhou Y, Lin DW, Lissel F, Lin P, To JWF, Xie T, England K, Zhang Y, Bao Z. Surpassing the Exciton Diffusion Limit in Single-Walled Carbon Nanotube Sensitized Solar Cells. ACS Nano 2016; 10:11258-11265. [PMID: 28024326 DOI: 10.1021/acsnano.6b06358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Semiconducting single-walled carbon nanotube (s-SWNT) light sensitized devices, such as infrared photodetectors and solar cells, have recently been widely reported. Despite their excellent individual electrical properties, efficient carrier transport from one carbon nanotube to another remains a fundamental challenge. Specifically, photovoltaic devices with active layers made from s-SWNTs have suffered from low efficiencies caused by three main challenges: the overwhelming presence of high-bandgap polymers in the films, the weak bandgap offset between the LUMO of the s-SWNTs and the acceptor C60, and the limited exciton diffusion length from one SWNT to another of around 5 nm that limits the carrier extraction efficiency. Herein, we employ a combination of processing and device architecture design strategies to address each of these transport challenges and fabricate photovoltaic devices with s-SWNT films well beyond the exciton diffusion limit of 5 nm. While our solution processing method minimizes the presence of undesired polymers in our active films, our interfacial designs led to a significant increase in current generation with the addition of a highly doped C60 layer (n-doped C60), resulting in increased carrier separation efficiency from the s-SWNTs films. We create a dense interconnected nanoporous mesh of s-SWNTs using solution shearing and infiltrate it with the acceptor C60. Thus, our final engineered bulk heterojunction allows carriers from deep within to be extracted by the C60 registering a 10-fold improvement in performance from our preliminary structures.
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Affiliation(s)
- Ghada I Koleilat
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Michael Vosgueritchian
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Ting Lei
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Yan Zhou
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Debora W Lin
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Franziska Lissel
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Pei Lin
- School of Materials Science and Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China
| | - John W F To
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Tian Xie
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Kemar England
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Yue Zhang
- School of Materials Science and Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China
| | - Zhenan Bao
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
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19
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Zhang MJ, Wang N, Pang SP, Lv Q, Huang CS, Zhou ZM, Ji FX. Carrier Transport Improvement of CH 3NH 3PbI 3 Film by Methylamine Gas Treatment. ACS Appl Mater Interfaces 2016; 8:31413-31418. [PMID: 27797470 DOI: 10.1021/acsami.6b10418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recently, perovskite solar cells with high photovoltaic performance based on methylammonium lead halide have attracted great interest due to the superior physical properties of the perovskite optical absorption layer. Here, we investigate the interface carrier transport properties of CH3NH3PbI3 film by applying the reported treatment with methylamine gas, to reveal the possible mechanism of high performance perovskite-sensitized solar cell results. It is found that the crystal structure and surface morphology are effectively improved by the room-temperature repair of methylamine atmosphere. The preferred 110 orientation results in a slightly larger band gap, which may contribute to the better energy level matching and carrier transport. Further investigations on relaxation time and electron mobility confirm the significantly enhanced carrier diffusion length, revealing the important role of optimized crystallization on charge transport properties, which may be helpful to seek high-powered perovskite solar cells by optimizing the perovskite synthetic process.
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Affiliation(s)
- Ming-Jia Zhang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Ning Wang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Shu-Ping Pang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Qing Lv
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Chang-Shui Huang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Zhong-Min Zhou
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
| | - Fu-Xiang Ji
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, P.R. China
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20
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Carey GH, Levina L, Comin R, Voznyy O, Sargent EH. Record Charge Carrier Diffusion Length in Colloidal Quantum Dot Solids via Mutual Dot-To-Dot Surface Passivation. Adv Mater 2015; 27:3325-3330. [PMID: 25899173 DOI: 10.1002/adma.201405782] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/11/2015] [Indexed: 06/04/2023]
Abstract
Through a combination of chemical and mutual dot-to-dot surface passivation, high-quality colloidal quantum dot solids are fabricated. The joint passivation techniques lead to a record diffusion length for colloidal quantum dots of 230 ± 20 nm. The technique is applied to create thick photovoltaic devices that exhibit high current density without losing fill factor.
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Affiliation(s)
- Graham H Carey
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Larissa Levina
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Riccardo Comin
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, 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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21
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Abstract
Photovoltaic devices based on lead iodide perovskite films have seen rapid advancements, recently achieving an impressive 17.9% certified solar power conversion efficiency. Reports have consistently emphasized that the specific choice of growth conditions and chemical precursors is central to achieving superior performance from these materials; yet the roles and mechanisms underlying the selection of materials processing route is poorly understood. Here we show that films grown under iodine-rich conditions are prone to a high density of deep electronic traps (recombination centers), while the use of a chloride precursor avoids the formation of key defects (Pb atom substituted by I) responsible for short diffusion lengths and poor photovoltaic performance. Furthermore, the lowest-energy surfaces of perovskite crystals are found to be entirely trap-free, preserving both electron and hole delocalization to a remarkable degree, helping to account for explaining the success of polycrystalline perovskite films. We construct perovskite films from I-poor conditions using a lead acetate precursor, and our measurement of a long (600 ± 40 nm) diffusion length confirms this new picture of the importance of growth conditions.
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Affiliation(s)
- Andrei Buin
- Department of Electrical and Computer Engineering, The University of Toronto , Toronto, ON M5S 3G4, Canada
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22
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Wehrenfennig C, Eperon GE, Johnston MB, Snaith HJ, Herz LM. High charge carrier mobilities and lifetimes in organolead trihalide perovskites. Adv Mater 2014; 26:1584-9. [PMID: 24757716 PMCID: PMC4722848 DOI: 10.1002/adma.201305172] [Citation(s) in RCA: 1011] [Impact Index Per Article: 101.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/13/2013] [Indexed: 05/17/2023]
Abstract
Organolead trihalide perovskites are shown to exhibit the best of both worlds: charge-carrier mobilities around 10 cm2 V−1 s−1 and low bi-molecular charge-recombination constants. The ratio of the two is found to defy the Langevin limit of kinetic charge capture by over four orders of magnitude. This mechanism causes long (micrometer) charge-pair diffusion lengths crucial for flat-heterojunction photovoltaics.
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Affiliation(s)
| | - Giles E Eperon
- Oxford University, Clarendon LaboratoryParks Road, Oxford, OX1 3PU, UK
| | | | - Henry J Snaith
- Oxford University, Clarendon LaboratoryParks Road, Oxford, OX1 3PU, UK
| | - Laura M Herz
- Oxford University, Clarendon LaboratoryParks Road, Oxford, OX1 3PU, UK
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23
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Zhao Y, Nardes AM, Zhu K. Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length. J Phys Chem Lett 2014; 5:490-494. [PMID: 26276597 DOI: 10.1021/jz500003v] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on the effect of TiO2 film thickness on charge transport and recombination in solid-state mesostructured perovskite CH3NH3PbI3 (via one-step coating) solar cells using spiro-MeOTAD as the hole conductor. Intensity-modulated photocurrent/photovoltage spectroscopies show that the transport and recombination properties of solid-state mesostructured perovskite solar cells are similar to those of solid-state dye-sensitized solar cells. Charge transport in perovskite cells is dominated by electron conduction within the mesoporous TiO2 network rather than from the perovskite layer. Although no significant film-thickness dependence is found for transport and recombination, the efficiency of perovskite cells increases with TiO2 film thickness from 240 nm to about 650-850 nm owing primarily to the enhanced light harvesting. Further increasing film thickness reduces cell efficiency associated with decreased fill factor or photocurrent density. The electron diffusion length in mesostructured perovskite cells is longer than 1 μm for over four orders of magnitude of light intensity.
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Affiliation(s)
- Yixin Zhao
- Chemical and Materials Science Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Alexandre M Nardes
- Chemical and Materials Science Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Kai Zhu
- Chemical and Materials Science Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
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24
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Isoda S. Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes. J Environ Sci (China) 2013; 25 Suppl 1:S172-S179. [PMID: 25078825 DOI: 10.1016/s1001-0742(14)60651-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Power conversion efficiency of p-i-n type macrocrystalline silicon (µc-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type μc-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 μm) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.
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Affiliation(s)
- Satoru Isoda
- Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Hukaya, Saitama 3690293, Japan.
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25
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Kato S, Kurokawa Y, Miyajima S, Watanabe Y, Yamada A, Ohta Y, Niwa Y, Hirota M. Improvement of carrier diffusion length in silicon nanowire arrays using atomic layer deposition. Nanoscale Res Lett 2013; 8:361. [PMID: 23968156 PMCID: PMC3765971 DOI: 10.1186/1556-276x-8-361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 08/05/2013] [Indexed: 05/16/2023]
Abstract
To achieve a high-efficiency silicon nanowire (SiNW) solar cell, surface passivation technique is very important because a SiNW array has a large surface area. We successfully prepared by atomic layer deposition (ALD) high-quality aluminum oxide (Al2O3) film for passivation on the whole surface of the SiNW arrays. The minority carrier lifetime of the Al2O3-depositedSiNW arrays with bulk silicon substrate was improved to 27 μs at the optimum annealing condition. To remove the effect of bulk silicon, the effective diffusion length of minority carriers in the SiNW array was estimated by simple equations and a device simulator. As a result, it was revealed that the effective diffusion length in the SiNW arrays increased from 3.25 to 13.5 μm by depositing Al2O3 and post-annealing at 400°C. This improvement of the diffusion length is very important for application to solar cells, and Al2O3 deposited by ALD is a promising passivation material for a structure with high aspect ratio such as SiNW arrays.
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Affiliation(s)
- Shinya Kato
- Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Yasuyoshi Kurokawa
- Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
- PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0076, Japan
| | - Shinsuke Miyajima
- Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Yuya Watanabe
- Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Akira Yamada
- Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
- Photovoltaics Research Center (PVREC), Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Yoshimi Ohta
- Advanced Materials Laboratory, Nissan Research Center, Yokosuka, Kanagawa 237-8523, Japan
| | - Yusuke Niwa
- Advanced Materials Laboratory, Nissan Research Center, Yokosuka, Kanagawa 237-8523, Japan
| | - Masaki Hirota
- Advanced Materials Laboratory, Nissan Research Center, Yokosuka, Kanagawa 237-8523, Japan
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26
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Park JK, Kang JC, Kim SY, Son BH, Park JY, Lee S, Ahn YH. Diffusion Length in Nanoporous Photoelectrodes of Dye-Sensitized Solar Cells under Operating Conditions Measured by Photocurrent Microscopy. J Phys Chem Lett 2012; 3:3632-3638. [PMID: 26290998 DOI: 10.1021/jz301751j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We determined the carrier diffusion lengths in nanoporous layers of dye-sensitized solar cells by using scanning photocurrent microscopy. The diffusion lengths were found to be 60-100 μm for the conventional cells. In addition, we found a correlation between the carrier diffusion lengths and the cell efficiency, which proved that improvement in the diffusion length is one of the crucial factors for optimizing device performance. The diffusion length was measured for various operating conditions by varying parameters such as solar light intensity and applied electrical voltage. In particular, we observed electric-field-driven, carrier transport phenomena (i.e., drift current) in modified cells. Fitting with the drift-diffusion model enabled us to extract the electric field strengths present in the TiO2 nanoporous layer.
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Affiliation(s)
- Jae-Ku Park
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - Ji-Chul Kang
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - Sang Yong Kim
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - B H Son
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - Ji-Yong Park
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - Soonil Lee
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
| | - Y H Ahn
- Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749, Korea
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27
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Nafie N, Lachiheb MA, Bouaicha M. Effect of etching time on morphological, optical, and electronic properties of silicon nanowires. Nanoscale Res Lett 2012; 7:393. [PMID: 22799265 PMCID: PMC3479071 DOI: 10.1186/1556-276x-7-393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/08/2012] [Indexed: 06/01/2023]
Abstract
Owing to their interesting electronic, mechanical, optical, and transport properties, silicon nanowires (SiNWs) have attracted much attention, giving opportunities to several potential applications in nanoscale electronic, optoelectronic devices, and silicon solar cells. For photovoltaic application, a superficial film of SiNWs could be used as an efficient antireflection coating. In this work we investigate the morphological, optical, and electronic properties of SiNWs fabricated at different etching times. Characterizations of the formed SiNWs films were performed using a scanning electron microscope, ultraviolet-visible-near-infrared spectroscopy, and light-beam-induced-current technique. The latter technique was used to determine the effective diffusion length in SiNWs films. From these investigations, we deduce that the homogeneity of the SiNWs film plays a key role on the electronic properties.
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Affiliation(s)
- Nesma Nafie
- Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l’Energie, Technopole de Borj-Cedria, BP 95, Hammam-Lif, Tunis, 2050, Tunisia
| | - Manel Abouda Lachiheb
- Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l’Energie, Technopole de Borj-Cedria, BP 95, Hammam-Lif, Tunis, 2050, Tunisia
| | - Mongi Bouaicha
- Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l’Energie, Technopole de Borj-Cedria, BP 95, Hammam-Lif, Tunis, 2050, Tunisia
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28
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Gonzalez-Vazquez JP, Morales-Flórez V, Anta JA. How Important is Working with an Ordered Electrode to Improve the Charge Collection Efficiency in Nanostructured Solar Cells? J Phys Chem Lett 2012; 3:386-393. [PMID: 26285856 DOI: 10.1021/jz2015988] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The collection efficiency of carriers in solar cells based on nanostructured electrodes is determined for different degrees or morphological one-dimensional order. The transport process is modeled by random walk numerical simulation in a mesoporous electrode that resembles the morphology of nanostructured TiO2 electrodes typically used in dye-sensitized solar cells and related systems. By applying an energy relaxation procedure in the presence of an external potential, a preferential direction is induced in the system. It is found that the partially ordered electrode can almost double the collection efficiency with respect to the disordered electrode. However, this improvement depends strongly on the probability of recombination. For too rapid or too slow recombination, working with partially ordered electrodes will not be beneficial. The computational method utilized here makes it possible to relate the charge collection efficiency with morphology. The collection efficiency is found to reach very rapidly a saturation value, meaning that, in the region of interest, a slight degree of ordering might be sufficient to induce a large improvement in collection efficiency.
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Affiliation(s)
| | - Victor Morales-Flórez
- ‡Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Av. Américo Vespucio 49, E-41092 Sevilla, Spain
| | - Juan A Anta
- †Área de Química Física, Universidad Pablo de Olavide, Sevilla, Spain
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