posted on 2020-08-28, 19:14authored byZhen Bao, Yu-Jui Tseng, Wenwu You, Wei Zheng, Xueyuan Chen, Sebastian Mahlik, Agata Lazarowska, Tadeusz Lesniewski, Marek Grinberg, Chonggeng Ma, Weihao Sun, Wuzong Zhou, Ru-Shi Liu, J. Paul Attfield
Cs4PbBr6 is regarded as an outstanding luminescent
material with good thermal stability and optical performance. However,
the mechanism of green emission from Cs4PbBr6 has been controversial. Here we show that isolated CsPbBr3 nanoparticles embedded within a Cs4PbBr6 matrix
give rise to a “normal” green luminescence while superfluorescence
at longer wavelengths is suppressed. High-resolution transmission
electron microscopy shows that the embedded CsPbBr3 nanoparticles
are around 3.8 nm in diameter and are well-separated from each other,
perhaps by a strain-driven mechanism. This mechanism may enable other
efficient luminescent composites to be developed by embedding optically
active nanoparticles epitaxially within inert host lattices.