High Photoluminescence Efficiency and Optically Pumped Lasing in Solution-Processed Mixed Halide Perovskite Semiconductors

TLDR

Organic–metallic lead halide perovskites exhibit excellent photovoltaic performance, and studying their photophysics helps elucidate charge generation, recombination, and potential for other optoelectronic applications. In pristine CH₃NH₃PbI₃–ₓClₓ perovskites, photoexcitation generates free carriers within 1 ps that recombine bimolecularly over tens to hundreds of nanoseconds, and the authors use this material to build an optically pumped vertical‑cavity laser with perovskite sandwiched between dielectric and gold mirrors. Solution‑processed CH₃NH₃PbI₃–ₓClₓ films exhibit photoluminescence quantum efficiencies up to 70 % and long carrier lifetimes, making them unprecedentedly bright inorganic semiconductors ideal for photovoltaic diode applications.

Abstract

The study of the photophysical properties of organic–metallic lead halide perovskites, which demonstrate excellent photovoltaic performance in devices with electron- and hole-accepting layers, helps to understand their charge photogeneration and recombination mechanism and unravels their potential for other optoelectronic applications. We report surprisingly high photoluminescence (PL) quantum efficiencies, up to 70%, in these solution-processed crystalline films. We find that photoexcitation in the pristine CH3NH3PbI3–xClx perovskite results in free charge carrier formation within 1 ps and that these free charge carriers undergo bimolecular recombination on time scales of 10s to 100s of ns. To exemplify the high luminescence yield of the CH3NH3PbI3–xClx perovskite, we construct and demonstrate the operation of an optically pumped vertical cavity laser comprising a layer of perovskite between a dielectric mirror and evaporated gold top mirrors. These long carrier lifetimes together with exceptionally high luminescence yield are unprecedented in such simply prepared inorganic semiconductors, and we note that these properties are ideally suited for photovoltaic diode operation.