Lead‐Free Silver‐Bismuth Halide Double Perovskite Nanocrystals. Issue 19 (26th March 2018)

• Record Type: Journal Article
• Authors: Yang, Bin; Chen, Junsheng; Yang, Songqiu; Hong, Feng; Sun, Lei; Han, Peigeng; Pullerits, Tõnu; Deng, Weiqiao; Han, Keli
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 19(2018)
• Page Start: 5359
• Page End: 5363
• Publication Date: 2018-03-26
• Subjects: bismuth -- charge carriers -- double perovskites -- nanocrystals -- silver; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201800660
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: 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 Cs2 AgBiX6 (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 Cs2 AgBiBr6 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 Cs2 AgBiCl6 NCs. These results suggest that the double perovskite NCs could be potential materials for optoelectronic applications by better controlling the surface defects. Abstract : Lead‐free double perovskite Cs2 AgBiX6 (X=Cl, Br, I) nanocrystals (NCs) have been synthesized. The photoluminescence of Cs2 AgBiCl6 NCs can be increased by 100 times by using surfactant to passivate the surface defects.