High-efficiency perovskite-polymer bulk heterostructure light-emitting diodes

Perovskite-based optoelectronic devices are gaining much attention owing to their remarkable performance and low processing cost, particularly for solar cells. However, for perovskite light-emitting diodes, non-radiative charge recombination has limited the electroluminescence efficiency. Here we demonstrate perovskite-polymer bulk heterostructure light-emitting diodes exhibiting external quantum efficiencies of up to 20.1% (at current densities of 0.1-1 mA cm(-2)). The light-emitting diode emissive layer comprises quasi-two-dimensional and three-dimensional (2D/3D) perovskites and an insulating polymer. Photogenerated excitations migrate from quasi-2D to lower-energy sites within 1 ps, followed by radiative bimolecular recombination in the 3D regions. From near-unity external photoluminescence quantum efficiencies and transient kinetics of the emissive layer with and without charge-transport contacts, we find non-radiative recombination pathways to be effectively eliminated, consistent with optical models giving near 100% internal quantum efficiencies. Although the device brightness and stability (T-50 = 46 h in air at peak external quantum efficiency) require further improvement, our results indicate the significant potential of perovskite-based photon sources.Funding Agencies|Cambridge Trust; China Scholarship Council; VINNMER Marie-Curie Fellowship; Royal Society Newton-Bhabha International Fellowship; UAEs Distinguished Student Scholarship Program; UAEs Ministry of Presidential Affairs; Engineering and Physical Sciences Research Council (EPSRC); Thousand Talent Program; EPSRC; European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme [670405]