Journal Article Ruddlesden-Popper perovskites light-emitting diodes pure-red light-emitting diodes CsPb(Br/I)3 nanocrystals Fluorescent Dyes MicroRNAs Organic Chemicals Penaeus vannamei Research Support, Non-U.S. Gov't cation-π interactions delayed fluorescence electroluminescence exciplex free carrier generation halide vacancies hepatopancreas hybrid white OLEDs layered perovskites low-temperature stress microRNA organic photovoltaics perovskite nanocrystals phase separation phosphorescence pure red self-doping effect single emissive layers single-layer device solar cells