Doubly Stabilized Perovskite Nanocrystal Luminescence Downconverters

Abstract Halide perovskite nanocrystals (NCs) have emerged as a promising material for applications ranging from light‐emitting diodes (LEDs) to solar cells and photodetectors. Still, several issues impede the realization of the NCs’ full potential, most notably their susceptibility to degradation from environmental stress. This work demonstrates highly stable perovskite NCs with quantum yields (QYs) as high as 95% by exploiting a ligand‐assisted copolymer nanoreactor‐based synthesis. The organic ligands thereby serve a dual function by enhancing the uptake of precursors and passivating the NCs. The polymer micelles and ligands thus form a double protection system, shielding the encapsulated NCs from water‐, heat‐ and UV‐light‐induced degradation. The authors demonstrate optoelectronic integrability by incorporating the perovskite NCs as spectrally pure downconverters on top of a deep‐blue‐emitting organic LED. These results establish a way of stabilizing perovskite NCs for optoelectronics while retaining their excellent optical properties.