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

References:

1. N. S. Makarov, S. Guo, O. Isaienko, W. Liu, I. Robel, and V. I. Klimov, Spectral and Dynamical Properties of Single Excitons, Biexcitons, and Trions in Cesium–Lead-Halide Perovskite Quantum Dots, Nano Lett. 16, 2349-2362 (2016)

2. W. Liu, Q. Lin, H. Li, K. Wu, I. Robel, J. M. Pietryga, and V. I. Klimov, Mn²⁺-Doped Lead Halide Perovskite Nanocrystals with Dual-Color Emission Controlled by Halide Content, J. Am. Chem. Soc. 138, 14954-14961 (2016)