Highly compact CsPbBr3 perovskite film decorated by PEO for light-emitting diodes

Abstract

Inorganic perovskite light-emitting diodes (PeLEDs) with full coverage and compact films were realized by doping a certain amount of PEO into perovskite emitting layer. The additive PEO (Polyethylene oxide) can not only improve the coverage of films by physically filling the pin-holes of crystal boundaries but also act as a protective layer to passivate the films, which successfully reduce the rate of non-radiative recombination, and enhance photoluminescence quantum yield (PLQY) of the CsPbBr3 films. In addition, PEO can also decrease the surface roughness of the perovskite films. As a result, the addition of PEO can improve the transport capability of carriers in PeLEDs. By optimizing the concentration of PEO, a maximum external quantum efficiency (EQE) of 0.26% and brightness of 1432 cd/m2 were achieved, which is significantly improved compared with previous work. The results presented in this paper shows that the additive PEO in perovskite precursor solution paves a new way for the application in PeLEDs.