Excitons and Biexciton Dynamics in Single CsPbBr₃ Perovskite Quantum Dots

Abstract

Colloidal lead halide perovskite quantum dots, due to their optical versatility and facile solution processability, have been recently recognized as components of various optoelectronic devices. Detailed understanding of their exciton recombination dynamics at the single-particle level is necessary for utilizing their full potential. We conducted spectroscopic studies of the excitons and biexciton dynamics in single CsPbBr 3 perovskite quantum dots. It was found that while the rates of radiative recombination remain essentially constant, the overall relaxation process is dominated by nonradiative recombination of single excitons and biexcitons. The radiative lifetime scaling is determined to be ∼1.0 for single exciton and ∼4.4 for biexcitons. A linear dependence of fluorescence lifetime vs intensity distribution agrees well with the prediction of the model of multiple recombination centers. The blinking mechanism of CsPbBr 3 quantum dots is addressed by considering the trion states under higher excitation powers.

Memories in the photoluminescence intermittency of single cesium lead bromide nanocrystals

“…PL intermittency has been observed in cesium lead halide perovskite NCs [ 4 , [21][22][23][24][25] ] over the past few years. Different models that were initially proposed for II-VI semiconductor NCs [ 19 , 26 ] have been invoked to rationalize the PL blinking of these NCs.…”

Verification of Type-A and Type-B-HC Blinking Mechanisms of Organic–Inorganic Formamidinium Lead Halide Perovskite Quantum Dots by FLID Measurements

“…These two types of blinking mechanisms could be used for conventional semiconductor QDs 15-20 and also, possibly, for PQDs 13,21-23 . In addition, several researchers have suggested in their recent publications, that the two types of blinking simultaneously contribute to PQD blinking [24][25][26][27] .Analysis of fluorescence lifetime intensity distribution (FLID) has been regarded as a very effective experimental approach to distinguish between these two types of blinking mechanisms 18,19 . While the FLID trajectory for type-A blinking is typically a curved line 18,19 , that of type-B blinking can be further divided into two sub www.nature.com/scientificreports www.nature.com/scientificreports/ algorithms, coded utilizing the MATLAB software, and fitted employing the ORIGIN 2016 software.…”

“…These two types of blinking mechanisms could be used for conventional semiconductor QDs 15-20 and also, possibly, for PQDs 13,21-23 . In addition, several researchers have suggested in their recent publications, that the two types of blinking simultaneously contribute to PQD blinking [24][25][26][27] .…”

“…Several scholars identified type-A blinking for PQDs using the FLID characteristics and assigned the observed short lifetimes to the trion 13,21,24 . However, the lifetimes of the PQD trion states have been reported to be vastly different, such as 170 ps 21 , 410 ps 28 , 2 ns 24,25 , and 5.8 ns 29 . These values could be comparable with the low-emission state lifetime in type B-BC blinking [23][24][25] .…”

“…However, the lifetimes of the PQD trion states have been reported to be vastly different, such as 170 ps 21 , 410 ps 28 , 2 ns 24,25 , and 5.8 ns 29 . These values could be comparable with the low-emission state lifetime in type B-BC blinking [23][24][25] . Moreover, the FLID trajectories of type-A blinking of PQDs in previous studies were not clearly verified compared to the conventional (cadmium chalcogenides) QD.…”