# Quantum Interference in a Single Perovskite Nanocrystal

## TL;DR

This paper demonstrates coherent optical properties in single perovskite CsPbI3 nanocrystals, overcoming previous spectral diffusion issues, and highlights their potential for quantum information applications.

## Contribution

It provides the first evidence of quantum interference and coherence in single perovskite nanocrystals, a significant step beyond traditional optoelectronic uses.

## Key findings

- PL linewidth smaller than 20 μeV for neutral excitons
- Dephasing time of about 10 ps for charged excitons
- Stable PL spectrum at the single-particle level

## Abstract

Coherent manipulation of the exciton wave function in a single semiconductor colloidal nanocrystal (NC) has been actively pursued in the past decades without any success, mainly due to the bothersome existences of the spectral diffusion and the photoluminescence (PL) blinking effects. Such optical deficiencies can be naturally avoided in the newly-developed colloidal NCs of perovskite CsPbI3, leading to the PL spectrum with a stable intensity at the single-particle level. Meanwhile, from the first-order photon correlation measurement, a PL linewidth smaller than 20 {\mu}eV is estimated for the emission state of the neutral excitons in a single CsPbI3 NC. Moreover, a dephasing time of about 10 ps can be extracted from the quantum interference measurement on the absorption state of the charged excitons. This first demonstration of a coherent optical feature will advance single colloidal NCs into the quantum information regime, opening up an alternative yet prospective research direction beyond their traditional applications such as in optoelectronic devices and bioimaging.

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Source: https://tomesphere.com/paper/1901.01650