Influence of a lecithin additive on the performance of all-inorganic perovskite light-emitting diodes

All-inorganic halide perovskites with superior optoelectronic properties are promising materials for efficient perovskite light-emitting diodes. However, they usually suffer from a large grain size (hundreds of nanometers), high surface roughness and poor stability during the spin coating process. Here, we report a facile strategy to fabricate a uniform and flat CsPbBr3 film. A small amount of lecithin (LE) introduced into CsPbBr3 precursor solution can promote the formation of small CsPbBr3 grains that remarkably improve the uniformity of perovskite films with a surface roughness of about 2.2 nm. Furthermore, the CsPbBr3–LE films display excellent fluorescence stability in ambient air and LED devices based on the CsPbBr3–5 wt% LE film exhibit a current efficiency (CE) of 24 cd A−1 with an external quantum efficiency (EQE) of 6.5%. Therefore, it is anticipated that the findings of the present study will have great potential to boost the development of PeLEDs.