Polymer–perovskite blend light-emitting diodes using a self-compensated heavily doped polymeric anode

Perovskite-based light-emitting diodes (PeLEDs) are drawing great attention due to their remarkable performance and ease of processing. Nevertheless, a critical aspect is the perovskite film formation on top of solution-processed anodes such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Use of conventional PEDOT:PSS anodes gives rise to high leakage currents that mask the hole transport properties of the perovskite semiconductor. Here, we show a feasible approach to overcome this constraint by implementing a solution-processed, self-compensated, hole-doped triarylamine-fluorene copolymer (p-pTFF-C2F5SIS) with a work function of 5.85 eV as the anode for polymer–perovskite blend LED devices. Highly efficient hole injection was obtained, near that of evaporated MoOx. Hole-only devices reveal that the hole transport in the polymer–perovskite blend is trap-limited. PeLEDs with the ultrahigh-workfunction p-pTFF-C2F5SIS anode show much lower leakage and much better stability in current-voltage and light output characteristics than those with the PEDOT:PSSH anode.