TY - JOUR
T1 - Solution Processable Direct Bandgap Copper-Silver-Bismuth Iodide Photovoltaics
T2 - Compositional Control of Dimensionality and Optoelectronic Properties
AU - Pai, Narendra
AU - Chatti, Manjunath
AU - Fürer, Sebastian O.
AU - Scully, Andrew D.
AU - Raga, Sonia R.
AU - Rai, Nitish
AU - Tan, Boer
AU - Chesman, Anthony S.R.
AU - Xu, Zhou
AU - Rietwyk, Kevin J.
AU - Reddy, Saripally Sudhaker
AU - Hora, Yvonne
AU - Sepalage, Gaveshana A.
AU - Glück, Nadja
AU - Lira-Cantú, Monica
AU - Bach, Udo
AU - Simonov, Alexandr N.
N1 - Publisher Copyright:
© 2022 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.
PY - 2022/8/25
Y1 - 2022/8/25
N2 - 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.
AB - 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.
KW - Cu AgBiI
KW - CuAgBiI
KW - solar cells
KW - thin film
UR - http://www.scopus.com/inward/record.url?scp=85134381200&partnerID=8YFLogxK
U2 - 10.1002/aenm.202201482
DO - 10.1002/aenm.202201482
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AN - SCOPUS:85134381200
SN - 1614-6832
VL - 12
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 32
M1 - 2201482
ER -