Iontronic Electroluminescence Devices: Comparing Halide Perovskites and Conjugated Polymers

Halide perovskites and polymer light-emitting electrochemical cells exhibit similar iontronic properties, wherein ion migration under an external bias can be coupled with electronic doping of the perovskites and conjugated polymers, leading to efficient electroluminescence devices with an ultrasimplified device architecture. In this work, it is discovered that a major difference exists between halide perovskites and polymer light-emitting electrochemical cells through low-temperature measurements of photovoltaic properties, photoluminescence spectra, and current-voltage characteristics using precharged devices. In perovskites, ion migration is simultaneously accompanied by doping, and both n-type and p-type doping can occur at a bias much lower than the bandgap/e of the perovskite. On the contrary, ion migration in polymer light-emitting electrochemical cells leads to doping only when the bias exceeds the bandgap/e of the conjugated polymer.