Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
DOI: https://doi.org/10.29363/nanoge.hopv.2020.091
Publication date: 6th February 2020
Within the past few years, metal halide perovskites have been attracting significant interest due to their successful application to optoelectronic devices. These materials have been used in lasers, photodetectors, and most commonly, in photovoltaic devices and light emitting diodes. Despite the cheap and simple fabrication methods by which these materials are deposited, high quality perovskite films can be readily fabricated, and the power conversion efficiencies of lead halide perovskite solar cells are now approaching certified values of 23%. However, perovskite-based devices are yet to achieve their full potential. One of the major hindrances to achieving this potential is an incomplete understanding of perovskite surfaces and interfaces. Deficiencies at these interfaces may be responsible for the largest losses in perovskite based optoelectronic devices; hindering charge extraction, increasing non-radiative recombination rates and hysteresis, and significantly increasing the voltage loss perovskite photovoltaics. We propose surface doping of the perovskite material as a means to combat these interface deficiencies. Herein, we will discuss doping of the perovskite material at various interfaces using well-established charge-transfer dopants. We show the doping of the perovskite material through both solid-state NMR and surface characterisation techniques, and further characterise the material through photoluminescence measurements, showing a reduction in the non-radiative recombination. Using this method of interface doping, we show photovoltaic devices with reduced hysteresis, low voltage losses, steady-state power conversion efficiencies in excess of 20%, and improved stability. Additionally, we extend this approach beyond photovoltaics and show the beneficial impacts of this type of interface engineering on perovskite-based light emitting diodes.