Universal emission intermittency in quantum dots, nanorods, and nanowires

TL;DR

This paper discusses the universal power law blinking behavior of quantum dots, nanorods, and nanowires, highlighting the wide dynamic range of emission intermittency and its persistent mystery despite recent theoretical advances.

Contribution

It reveals the universal power law distribution of blinking times across various fluorophores and discusses recent progress in understanding this phenomenon.

Findings

Power law distribution of blinking times extends over nine orders of magnitude.

Exponents hover around -3/2, indicating a common underlying mechanism.

Dark states can last tens of seconds, yet emission recovers unexpectedly.

Abstract

Virtually all known fluorophores, including semiconductor nanoparticles, nanorods and nanowires exhibit unexplainable episodes of intermittent emission blinking. A most remarkable feature of the fluorescence intermittency is a universal power law distribution of on- and off-times. For nanoparticles the resulting power law extends over an extraordinarily wide dynamic range: nine orders of magnitude in probability density and five to six orders of magnitude in time. The exponents hover about the ubiquitous value of -3/2. Dark states routinely last for tens of seconds, which are practically forever on quantum mechanical time scales. Despite such infinite states of darkness, the dots miraculously recover and start emitting again. Although the underlying mechanism responsible for this phenomenon remains an enduring mystery and many questions remain, we argue that substantial theoretical progress has been made.