Keldysh tuning of photoluminescence in a lead halide perovskite crystal

TL;DR

This paper demonstrates how lead halide perovskites can be tuned using Keldysh physics to enhance photoluminescence, enabling sub-bandgap light emission and insights into strong-field light-matter interactions.

Contribution

It introduces a novel application of Keldysh tuning in lead halide perovskites for controlling photoluminescence and distinguishing excitation processes.

Findings

Bright sub-bandgap photoluminescence achieved

Distinction between photon-induced and electric-field-induced processes

Insights into non-equilibrium strong-field dynamics

Abstract

In 1964, Keldysh laid the groundwork for strong-field physics in atomic, molecular, and solid-state systems by delineating a ubiquitous transition from multiphoton absorption to quantum electron tunneling under intense AC driving forces. While both processes in semiconductors can generate carriers and result in photon emission through electron-hole recombination, the low quantum yields in most materials have hindered direct observation of the Keldysh crossover. Leveraging the large quantum yields of photoluminescence in lead halide perovskites, we show that we can not only induce bright light emission from extreme sub-bandgap light excitation but also distinguish between photon-induced and electric-field-induced processes. Our results are rationalized by the Landau-Dykhne formalism, providing insights into the non-equilibrium dynamics of strong-field light-matter interactions. These findings open new avenues for light upconversion and sub-bandgap photon detection, highlighting the potential of lead halide perovskites in advanced optoelectronic applications.