Intermittency of CsPbBr$_3$ perovskite quantum dots analyzed by an unbiased statistical analysis

TL;DR

This paper employs unbiased Bayesian statistical methods to analyze the intermittency and state switching behavior of CsPbBr$_3$ perovskite quantum dots, revealing complex multistate dynamics and aging effects.

Contribution

It introduces a Bayesian changepoint and state clustering approach for unbiased analysis of multistate emitters, specifically applied to perovskite quantum dots.

Findings

Perovskite quantum dots exhibit multiple gray states with brightness inversely related to decay rate.

Dots tend to return to bright states before switching to dim states.

Quantum dots explore all available states during dim phases.

Abstract

We analyze intermittency in intensity and fluorescence lifetime of CsPbBr$_3$ perovskite quantum dots by applying unbiased Bayesian inference analysis methods. We apply changepoint analysis (CPA) and a Bayesian state clustering algorithm to determine the timing of switching events and the number of states between which switching occurs in a statistically unbiased manner, which we have benchmarked particularly to apply to highly multistate emitters. We conclude that perovskite quantum dots display a plethora of gray states in which brightness broadly speaking correlates inversely with decay rate, confirming the multiple recombination centers model. We leverage the CPA partitioning analysis to examine aging and memory effects. We find that dots tend to return to the bright state before jumping to a dim state, and that when choosing a dim state they tend to explore the entire set of states available.