Light diffusing, down-converting perovskite-on-polymer microspheres

Abstract

Remote downconverters such as phosphors or quantum dots that are physically separated from blue light-emitting diode (LED) chips can strongly enhance the luminescence efficiency of solid-state lighting (SSL) and liquid-crystal displays (LCDs) because of their reduced light reabsorption. However, the high cost of traditional remote downconverters has limited their wide adoption in these applications. Herein, we report a one-step, general synthesis method that can convert commercial light-diffusing polymer microspheres into highly luminescent perovskite-based downconverters at an extremely low cost. Involving quick anti-solvent-induced heterogeneous nucleation, this method creates well-dispersed perovskite nanoparticles anchored onto polymer microspheres and the whole process takes only several seconds at room temperature without any complex experimental setups. Significantly, the as-synthesized perovskite-on-polymer microspheres (PPMs) offer widely tunable, highly saturated colors with light-diffusing capability. The pure green-emitting CsPbBr₃ manifests a high PL quantum yield of 70.6% and superior stability in water is also demonstrated. Dispersing these PPMs in polydimethylsiloxane (PDMS) resin, we further demonstrate a diffusive downconverting sheet, which is capable of turning blue LEDs into homogeneous light sources with a half-value angle (HVA) as high as 50°. These PPMs hold great promise to be adopted as a low-cost, high-quality replacement for the traditional, expensive remote downconverters in energy efficient SSL, LCDs and beyond.