Achieving high-performance in situ fabricated FAPbBr₃ and electroluminescence

Currently, metal halide perovskite films still encounter the issues of inferior film quality and interfacial electrical properties when they were constructed electroluminescence devices. Herein, efficient and pinhole-free perovskite emissive film was obtained on the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layer modified by an ultrathin LiF layer. Owing to the synergetic effect of the LiF interlayer, including better regulation of the perovskite film and a more balanced charge injection capability, an efficient green light-emitting diode based on the perovskite film was achieved with a maximum current efficiency of 25.6 cd/A, which is 58% higher than that of the control device with a plasma-treated PEDOT:PSS layer. Our results not only provide a facile strategy for acquiring efficient perovskite films but also circumvent the expensive and time-consuming plasma treatment process commonly used to improve the wetting properties of the underlying films.