Improved performance of quasi-two dimensional perovskite light-emitting diodes with l-phenylalanine-doped PEDOT:PSS hole transport layer

Perovskite light-emitting diodes (PeLEDs) have attracted considerable attention in optoelectronic devices due to their excellent performance. Here, the performance of PeLEDs was improved by utilizing l-phenylalanine-doped PEDOT:PSS as hole transport layer (HTL). The optimal device with l-phenylalanine doped HTL shows a maximum luminance of 3800 cd/m² and a maximum external quantum efficiency of 2.80%. Compared with the control device using pure PEDOT:PSS HTL, the maximum luminance was increased by 90%, and the maximum external quantum efficiency was increased by 154%, respectively. This is mainly due to the fact that PEDOT:PSS with l-phenylalanine doping optimizes the morphology of the perovskite film and suppresses the exciton quenching at the HTL/perovskite interface. In addition, moderate addition of l-phenylalanine can enhance the hole injection capability of HTL. These experimental results provide proof of amino acid-modified PEDOT:PSS as HTL and a basis for improving the performance of PeLEDs.