Abstract
The search for lead-free alternatives to lead-halide perovskite photovoltaic materials resulted in the discovery of copper(I)-silver(I)-bismuth(III) halides exhibiting promising properties for optoelectronic applications. The present work demonstrates a solution-based synthesis of uniform CuxAgBiI4+x thin films and scrutinizes the effects of x on the phase composition, dimensionality, optoelectronic properties, and photovoltaic performance. Formation of pure 3D CuAgBiI5 at x = 1, 2D Cu2AgBiI6 at x = 2, and a mix of the two at 1 < x < 2 is demonstrated. Despite lower structural dimensionality, Cu2AgBiI6 has broader optical absorption with a direct bandgap of 1.89 ± 0.05 eV, a valence band level at -5.25 eV, improved carrier lifetime, and higher recombination resistance as compared to CuAgBiI5. These differences are mirrored in the power conversion efficiencies of the CuAgBiI5 and Cu2AgBiI6 solar cells under 1 sun of 1.01 ± 0.06% and 2.39 ± 0.05%, respectively. The latter value is the highest reported for this class of materials owing to the favorable film morphology provided by the hot-casting method. Future performance improvements might emerge from the optimization of the Cu2AgBiI6 layer thickness to match the carrier diffusion length of ≈40–50 nm. Nonencapsulated Cu2AgBiI6 solar cells display storage stability over 240 days.
Original language | English |
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Article number | 2201482 |
Journal | Advanced Energy Materials |
Volume | 12 |
Issue number | 32 |
DOIs | |
State | Published - 25 Aug 2022 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2022 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.
Funding
The authors are highly grateful to Dr. Jiangfeng Lu (Wuhan University of Technology) for invaluable discussions, Mr. Philippe Holzhey (Oxford University) for assistance with PL measurements, Mr. D. Vowles (Monash University) for assistance with EBIC experiments, and to the Monash Centre for Electron Microscopy and Monash X-ray Platform for providing access to their characterization facilities used for some parts of this work. The authors acknowledge funding of this work by the Australian Government through the Australian Centre for Advanced Photovoltaics (ACAP), the Australian Renewable Energy Agency (ARENA), and the Australian Research Council through the Centre of Excellence in Exciton Science (CE170100026) and Future Fellowship to ANS (FT200100317). Responsibility for the views, information, or advice expressed herein is not accepted by the Australian Government. SRR acknowledges the support from “laCaixa” Foundation (ID 100010434; LCF/BQ/PI20/11760024). Open access publishing facilitated by Monash University, as part of the Wiley – Monash University agreement via the Council of Australian University Librarians. The authors are highly grateful to Dr. Jiangfeng Lu (Wuhan University of Technology) for invaluable discussions, Mr. Philippe Holzhey (Oxford University) for assistance with PL measurements, Mr. D. Vowles (Monash University) for assistance with EBIC experiments, and to the Monash Centre for Electron Microscopy and Monash X‐ray Platform for providing access to their characterization facilities used for some parts of this work. The authors acknowledge funding of this work by the Australian Government through the Australian Centre for Advanced Photovoltaics (ACAP), the Australian Renewable Energy Agency (ARENA), and the Australian Research Council through the Centre of Excellence in Exciton Science (CE170100026) and Future Fellowship to ANS (FT200100317). Responsibility for the views, information, or advice expressed herein is not accepted by the Australian Government. SRR acknowledges the support from “laCaixa” Foundation (ID 100010434; LCF/BQ/PI20/11760024).
Funders | Funder number |
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Australian University Librarians | |
Wiley – Monash University | |
Australian Centre for Advanced Photovoltaics | |
Australian Research Council | |
Monash University | |
Australian Renewable Energy Agency | |
Wuhan University of Technology | |
Centre of Excellence in Exciton Science | FT200100317, CE170100026 |
laCaixa” Foundation | 100010434, LCF/BQ/PI20/11760024 |
Keywords
- Cu AgBiI
- CuAgBiI
- solar cells
- thin film