Perovskite energy funnels for efficient white emission

Abstract

Doping Mn²⁺ into CsPbCl₃ nanocrystals (NCs) yields strong orange emission, while the related emission in Mn²⁺ doped CsPbBr₃ NCs is impaired seriously. This is mainly ascribed to back energy transfer from the Mn²⁺ dopant to the host. Doping Mn²⁺ into perovskites with multiple-quantum-well (MQW) structures may address this issue, where the energy funnels ensure a rapid energy transfer process, and thus resulting in a high photoluminescence quantum yield (PLQY). Here, we have developed an Ag⁺ assisted Mn²⁺ doping method in which Mn²⁺ can be easily doped into Br-based MQW perovskites. In this MQW perovskites, both nanoplatelets (NPLs) and NCs were formed simultaneously, where efficient energy transfer occurred from the NPLs with a higher energy bandgap to the NCs with a smaller energy bandgap, and then to the Mn²⁺ dopants. White lighting solution with a PLQY up to 98% has been acquired by altering the experimental parameters, such as reaction time and the Pb-to-Mn feed ratio. The successful doping of Mn²⁺ into CsPbBr₃ host has great significance and shows promising application for next-generation white lighting.

Keywords: Energy funnels; Mn(2+) doping; Perovskite nanomaterials; Quantum yield; WLED.