Creating chromaticity palettes and identifying white light emitters through nanocrystal megalibraries
Tong Cai, Donghoon Shin, Jun Li, David D. Xu, Jacob Pietryga, Ye Zhang, Chad A. Mirkin
Abstract
Halide perovskites are used to fabricate energy-efficient optoelectronic devices. Determining which compositions yield desired chromatic responses is challenging, especially when doping strategies are used. Here, we report a way of mapping the compositional space of halide perovskites to generate a light emission or “chromaticity” palette. Megalibraries consisting of millions of Mn 2+ -doped PEA 2 PbX 4 (PEA: phenethylammonium, X: halide anions) perovskite nanocrystals were synthesized to screen the compositions that led to specific emission profiles. The chromaticity palette allows one to identify single-composition white light emitters [PEA 2 Pb 1− y Mn y (Br 1− x I x ) 4 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1)], eliminating the need for trilayer structures in conventional white light-emitting diodes, which are prone to instability and complex device designs. Optical studies reveal that the dual-wavelength photoluminescence emission originates from exciton recombination and energy transfer processes. This study shows how emerging megalibrary capabilities can rapidly advance our understanding of the complex composition-structure-function relationships and be used to accelerate the discovery of next-generation optoelectronic materials.