White Electroluminescence from Perovskite–Organic Heterojunction

Despite extensive reports on red and green perovskite-based LEDs (PeLEDs), development of white PeLEDs remains limited by the low photoluminescence quantum yield of white-emitting perovskites and the undesired energy-transfer (ET) process occurring in multidomain Ruddlesden–Popper perovskites. While ET is beneficial for achieving efficient monochromatic emissions, the broadband spectrum required for white electroluminescence makes this phenomenon undesirable. Processing-induced physical separation of emitters has been proposed as an effective way to curb ET. Here, it is shown that by adopting a bilayered emitter configuration, achieved through a facile antisolvent-assisted spin-coating process, an increase in spatial separation between the blue perovskite and red emitting organic species employed can be realized. This, in turn, has allowed for effective reduction of ET efficiency, leading to a record efficiency of 1.3%, the highest achieved to date from a perovskite-based white electroluminescent device.