Artificial intelligence offers new opportunities for translucent displays. However, achieving translucent light-emitting diodes (LEDs) with high efficiency and high color purity remains a challenge. Here, we propose a strategy of using an alkali metal/inert metal (calcium/silver) bilayer metal electrode as a top electrode and perovskite nanocrystals as an emitter layer in the device structure, which allows us to not only fabricate excellent opaque LEDs but also manufacture highly efficient semitransparent LEDs with high color purity, total brightness (over 7000 cd m-2), total external quantum efficiency (over 12%), and 56% transmittance around 520 nm. This is the highest external quantum efficiency report about semitransparent LED based on perovskite materials or inorganic quantum dots so far, which presents great application potential in the field of translucent display with high color purity and wide color gamut.
Keywords: bilayer metal electrode; external quantum efficiency; light-emitting diodes; perovskite nanocrystals; semitransparent.