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Investigating Spatiotemporal Correlation of Multi-state Photoluminescence Intermittency in Organo-Lead Bromide Microcrystal Films
Journal
Journal of Physical Chemistry C
ISSN
19327447
Date Issued
2022-04-07
Author(s)
Pathoor, Nithin
Mukherjee, Amitrajit
Chowdhury, Arindam
Abstract
Recent observations of spatially correlated photoluminescence intermittency of spatially extended organo-lead halide perovskite microcrystals (MCs) has been explained via involvement of highly efficient, transient non-radiative traps and long-range communication between photogenerated carriers; however, the nature/origins of these quenchers as well as factors determining carrier communication remain obscure. Here, we studied the effect of excitation powers, energies, and crystal dimensions on the observed multi-state intermittency of methylammonium lead bromide (MAPbBr3) MCs. Our results support a model of involvement of a few quenchers in each crystal and effective diffusion of a subpopulation of charge carriers over entire crystals. Furthermore, we developed comprehensive analytical methods to quantify the extent of spatiotemporal blinking correlation, which establish a remarkably high (>0.9) correlation in flickering of spatially segregated MC grains. Surprisingly, however, we observe a transient yet dramatic loss of synchronicity in blinking for some fused MC grains, which point out to intermittent lack and re-establishment of inter-grain diffusion of photogenerated carriers, likely owing to a slow time-varying reversible change in the potential energy landscape in fused crystal grains. Finally, we report yet another intriguing phenomenon of transiently correlated and anti-correlated emissivity fluctuations between fused crystals, suggestive of directional excitation energy migration between adjacent grains.