Halide Perovskite Precursors Dope PEDOT:PSS

Abstract

AbstractHalide perovskite semiconductors find use in a broad range of optoelectronic applications including photovoltaic solar cells and light‐emitting diodes. In such devices the semiconductor is sandwiched in between interlayers for charge transport, extraction, or injection. When it comes to hole transport layers, the conducting polymer PEDOT:PSS has become an ubiquitous material. The halide perovskite thin film is commonly obtained by crystallization of precursors using solution processing on top of PEDOT:PSS. It is demonstrated here that such a widely spread technique is actually affecting the electrical properties of the underlying conducting polymer. The halide perovskite layer and precursors are drastically doping the PEDOT:PSS, its conductivity being increased by two orders of magnitude from 0.2 to 20 S cm−1. The depth of penetration of halide dopants is determined to be higher than 150 nm, superior to the usual thickness of PEDOT:PSS films. This phenomenon has important impact on diode leakage currents, on emission patterns of perovskite LEDs and on overestimated photocurrent density in perovskite solar cells embedding the PEDOT:PSS interlayer.