Extreme electron-photon interaction in perovskite glass

TL;DR

This paper demonstrates that electric pulse-induced structural disorder in lead halide perovskite glass significantly enhances light-matter interactions through photon-momentum mechanisms, leading to novel Raman scattering and photoluminescence phenomena.

Contribution

It introduces a new approach combining quantum confinement and structural disorder to boost electron-photon interactions in perovskite glass, revealing photon-momentum effects in disordered solids.

Findings

Enhanced photon-momentum-enabled Raman scattering and photoluminescence observed.

PL/ERS blinking linked to thermal fluctuations of structural units.

Room temperature spontaneous emission is increased via blinking synchronization.

Abstract

The interaction of light with solids can be dramatically enhanced owing to electron-photon momentum matching. This mechanism is driven by either quantum confinement or long-range structural correlations in media with crystal-liquid duality. In this paper, we address a new strategy based on both phenomena for enhancement of the light-matter interaction in a direct bandgap semiconductor - lead halide perovskite CsPbBr$_3$ - by using electric pulse-driven structural disorder. The disordered (glassy) state allows the generation of confined photons, and the formation of an electronic continuum of static/dynamic defect states across the forbidden gap (Urbach bridge). Both mechanisms underlie photon-momentum-enabled electronic Raman scattering (ERS) and single-photon anti-Stokes photoluminescence (PL) under sub-band pump. PL/ERS blinking is discussed to be associated with thermal fluctuations of cross-linked [PbBr$_6$]$^{4-}$ octahedra. Time-delayed synchronization of PL/ERS blinking causes enhanced spontaneous emission at room temperature. Our findings indicate the role of photon momentum in enhanced light-matter interactions in disordered and nanostructured solids.