High-luminance perovskite light-emitting diodes with high-polarity alcohol solvent treating PEDOT:PSS as hole transport layer

Background: Perovskite light-emitting diodes (PeLEDs) are fabricated with a structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/CH₃NH₃PbBr₃ (MAPbBr₃)/1,3,5-tris(2-N-phenylbenzimidazolyl) benzene (TPBi)/Ag.

Pedot: PSS films treated with alcohols including methanol, ethanol, and isopropanol are used to realize high-performance PeLEDs. Among them, by using PEDOT:PSS film treated by methanol as the hole transport layer, the PeLED with a maximum luminance of 2075 cd m^-2 and a maximum current efficiency of 0.38 cd A^-1 is achieved. Meanwhile, the result shows that the luminance of PeLEDs increases with the polarity of alcohol solvent. The conductivity of PEDOT:PSS films and crystallization of perovskite films are analyzed to gain a deep illumination into the influence of alcohol solvent treatment on device performance. It is also found that the treatment brings not only an improved hole injection capability but also a significantly enhanced crystallization of perovskite. This work indicates that our founding brings a simple and effective method to improve the device performance of PeLEDs.