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Lead‐Free Silver‐Bismuth Halide Double Perovskite Nanocrystals
Author(s) -
Yang Bin,
Chen Junsheng,
Yang Songqiu,
Hong Feng,
Sun Lei,
Han Peigeng,
Pullerits Tõnu,
Deng Weiqiao,
Han Keli
Publication year - 2018
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.201800660
Subject(s) - perovskite (structure) , halide , ultrafast laser spectroscopy , photoluminescence , nanocrystal , passivation , bismuth , chemistry , inorganic chemistry , charge carrier , materials science , photochemistry , spectroscopy , crystallography , nanotechnology , optoelectronics , physics , organic chemistry , layer (electronics) , quantum mechanics
Lead‐free perovskite nanocrystals (NCs) were obtained mainly by substituting a Pb 2+ cation with a divalent cation or substituting three Pb 2+ cations with two trivalent cations. The substitution of two Pb 2+ cations with one monovalent Ag + and one trivalent Bi 3+ cations was used to synthesize Cs 2 AgBiX 6 (X=Cl, Br, I) double perovskite NCs. Using femtosecond transient absorption spectroscopy, the charge carrier relaxation mechanism was elucidated in the double perovskite NCs. The Cs 2 AgBiBr 6 NCs exhibit ultrafast hot‐carrier cooling (<1 ps), which competes with the carrier trapping processes (mainly originate from the surface defects). Notably, the photoluminescence can be increased by 100 times with surfactant (oleic acid) added to passivate the defects in Cs 2 AgBiCl 6 NCs. These results suggest that the double perovskite NCs could be potential materials for optoelectronic applications by better controlling the surface defects.