High-efficiency and stable quantum dot light-emitting diodes with staircase V2O5/PEDOT:PSS hole injection layer interface barrier

Abstract

Abstract The main bottleneck causing lags in the application of transition metal oxides as substitutes for poly (3,4-ethylenedioxythiophene):poly (styrene-sulfonate) (PEDOT:PSS) are the relatively low level efficiencies of quantum dot light-emitting diodes (QLEDs), even though they can improve a device's stability. High-performance QLEDs are fabricated with long lifetimes using low-cost, reliable and all-solution-processed hole injection materials with a double hole injection layer (HIL) structure. Vanadium oxide (V2O5)/PEDOT:PSS double HILs offer a small staircase interface barrier, which enhance the hole injection and achieve a better charge balance. By using this double HIL regular planar architecture device, the maximum external quantum efficiency (ηEQE) reaches 18.09% and over 13355 h of lifetime. The related control PEDOT:PSS-based and V2O5-based QLEDs have maximum ηEQE of 13.79% and 9.13% with 6117 and 30881 h of lifetime, respectively. Due to the enhanced hole injection with the staircase interface barrier, the double HIL architecture QLEDs also have a high ηEQE above 15.00% over a wide range of 900–26000 cd m−2 with a low efficiency roll-off. These discoveries support the use of inorganic transition metal oxides as HILs for QLEDs with high efficiency and brightness for long operational lifetimes.