(Invited) Effects of Composition and Doping on the Optoelectronic Properties of Lead Halide Perovskite Nanocrystals

Abstract

Colloidally synthesized lead halide perovskite nanocrystals have been recently demonstrated as active materials with great promise for a range of applications, from high-efficiency photovoltaics to color-converting phosphors and light-emitting diodes. Tailoring their optical and electronic properties through various synthetic routes in order to meet application-specific design parameters requires a good understanding of structure-property relationships. Here, by using a variety of steady-state and time-resolved spectroscopies, we explore carrier-carrier and carrier-dopant interactions in cesium lead halide nanocrystals as their halide component (Cl, Br, I, and their mixture) and doping level (Mn2+) is continuously tuned through a wide parameter space. We quantify such fundamental optical properties as exciton radiative lifetimes, absorption cross-sections, and derive the degeneracies of the band-edge electron and hole states. We also characterize the rates of intraband cooling and nonradiative Auger recombination and evaluate the strength of exciton–exciton coupling.1 Through impurity doping with Mn2+ ions, we also introduce new optical functionalities such as dual-color emission and establish the mechanism of carrier-dopant coupling in these materials.2