In:
Angewandte Chemie, Wiley, Vol. 132, No. 35 ( 2020-08-24), p. 15303-15306
Abstract:
Environmentally friendly halide double perovskites with improved stability are regarded as a promising alternative to lead halide perovskites. The benchmark double perovskite, Cs 2 AgBiBr 6 , shows attractive optical and electronic features, making it promising for high‐efficiency optoelectronic devices. However, the large band gap limits its further applications, especially for photovoltaics. Herein, we develop a novel crystal‐engineering strategy to significantly decrease the band gap by approximately 0.26 eV, reaching the smallest reported band gap of 1.72 eV for Cs 2 AgBiBr 6 under ambient conditions. The band‐gap narrowing is confirmed by both absorption and photoluminescence measurements. Our first‐principles calculations indicate that enhanced Ag–Bi disorder has a large impact on the band structure and decreases the band gap, providing a possible explanation of the observed band‐gap narrowing effect. This work provides new insights for achieving lead‐free double perovskites with suitable band gaps for optoelectronic applications.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v132.35
DOI:
10.1002/ange.202005568
Language:
English
Publisher:
Wiley
Publication Date:
2020
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505868-5
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506609-8
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514305-6
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505872-7
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1479266-7
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505867-3
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506259-7
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