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Pure Cubic‐Phase Hybrid Iodobismuthates AgBi 2 I 7 for Thin‐Film Photovoltaics
Author(s) -
Kim Younghoon,
Yang Zhenyu,
Jain Ankit,
Voznyy Oleksandr,
Kim GiHwan,
Liu Min,
Quan Li Na,
García de Arquer F. Pelayo,
Comin Riccardo,
Fan James Z.,
Sargent Edward H.
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201603608
Subject(s) - materials science , thin film , photovoltaics , band gap , bismuth , annealing (glass) , spin coating , optoelectronics , photovoltaic system , chemical engineering , nanotechnology , composite material , metallurgy , ecology , engineering , biology
Bismuth‐based hybrid perovskites are candidates for lead‐free and air‐stable photovoltaics, but poor surface morphologies and a high band‐gap energy have previously limited these hybrid perovskites. A new materials processing strategy to produce enhanced bismuth‐based thin‐film photovoltaic absorbers by incorporation of monovalent silver cations into iodobismuthates is presented. Solution‐processed AgBi 2 I 7 thin films are prepared by spin‐coating silver and bismuth precursors dissolved in n‐butylamine and annealing under an N 2 atmosphere. X‐ray diffraction analysis reveals the pure cubic structure ( Fd 3 m ) with lattice parameters of a = b = c =12.223 Å. The resultant AgBi 2 I 7 thin films exhibit dense and pinhole‐free surface morphologies with grains ranging in size from 200–800 nm and a low band gap of 1.87 eV suitable for photovoltaic applications. Initial studies produce solar power conversion efficiencies of 1.22 % and excellent stability over at least 10 days under ambient conditions.