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Download filePhotoinduced Transformation of Cs2Au2Br6 into CsPbBr3 Nanocrystals
journal contribution
posted on 2022-03-28, 12:37 authored by Jishnudas Chakkamalayath, Gregory V. Hartland, Prashant V. KamatLead-free
halide double perovskites offer an environmentally friendly
alternative to lead halide perovskites for designing optoelectronic
solar cell devices. One simple approach to synthesize such double
halide perovskites is through metal ion exchange. CsPbBr3 nanocrystals undergo exchange of Pb2+ with Au(I)/Au(III)
to form double perovskite Cs2Au2Br6. When excited, a majority of the charge carriers undergo quick recombination
in contrast to long-lived charge carries of excited CsPbBr3 nanocrystals. This metal ion exchange process is reversible as one
can regenerate CsPbBr3 by adding excess PbBr2 to the suspension. Interestingly, when subjected to visible light
irradiation, Cs2Au2Br6 nanocrystals
eject reduced Au from the lattice as evidenced from the formation
of larger gold nanoparticles. The presence of residual Pb2+ ions in the suspension restores the original CsPbBr3 composition.
The results presented here provide insight into the dynamic nature
of Au within the perovskite lattice under both chemical and light
stimuli.
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metal ion exchangelived charge carrieslarger gold nanoparticlesenvironmentally friendly alternativedouble halide perovskitesadding excess pbbrvisible light irradiationlead halide perovskites6 </ sub3 </ sub2 </ subone simple approachnanocrystals undergo exchange2 +</ supnanocrystals leadlight stimuliresults presentedprovide insightphotoinduced transformationdynamic nature