Abstract:
Metal-halide perovskites exhibit bright and sharp luminescence, with properties that can be tuned over a wide range through solution processing [1,2]. In this talk, I will discuss our realisation of linearly polarised luminescence from perovskite light-emitting diodes (LEDs) [3]. This is achieved by self-assembling CsPbI3 nanoplatelets into an edge-up orientation. Through strong dielectric and quantum confinement, there is large exciton fine structure splitting. As a result, we achieve strong emission from out-of-plane dipoles for the optically bright excitons in these superlattices. In light-emitting diodes, this leads to a high degree of polarisation (DOP) of 74.4% in electroluminescence [3]. Exciton fine structure splitting could also enable improved performance in perovskite single photon emitters. Recent work from Bawendi and co-workers showed that metal-halide perovskite nanocrystals have a sufficiently long optical coherence to outcompete dephasing [4]. This enables demonstrations of single photon emitters with high purity and brightness, but currently low indistinguishability ~50%. I will discuss our perspectives on the potential of making use of exciton fine structure splitting to enhance the indistinguishability.