Lead-Free Silver-Bismuth Halide Double Perovskite Nanocrystals

Summary, in English

Lead-free perovskite nanocrystals (NCs) were obtained mainly by substituting a Pb²⁺ cation with a divalent cation or substituting three Pb²⁺ cations with two trivalent cations. The substitution of two Pb²⁺ cations with one monovalent Ag⁺ and one trivalent Bi³⁺ cations was used to synthesize Cs₂AgBiX₆ (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 Cs₂AgBiBr₆ 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 Cs₂AgBiCl₆ NCs. These results suggest that the double perovskite NCs could be potential materials for optoelectronic applications by better controlling the surface defects.

• Author: Bin Yang; Junsheng Chen; Songqiu Yang; Feng Hong; Lei Sun; Peigeng Han; Tõnu Pullerits; Weiqiao Deng; Keli Han
• Department/s: Chemical Physics; NanoLund: Centre for Nanoscience
• Publishing year: 2018-05-04
• Language: English
• Pages: 5359-5363
• Publication/Series: Angewandte Chemie - International Edition
• Volume: 57
• Issue: 19
• Links: http://dx.doi.org/10.1002/anie.201800660
• Document type: Journal article
• Publisher: John Wiley & Sons Inc.
• Topic: Physical Chemistry (including Surface- and Colloid Chemistry); Condensed Matter Physics (including Material Physics, Nano Physics)
• Keywords: bismuth; charge carriers; double perovskites; nanocrystals; silver
• Status: Published
• ISBN/ISSN/Other: ISSN: 1433-7851