Metal Halide Light-emitting Diode Based On Self-trapped Excitons

Solution processable metal halide materials are becoming one of the most competitive core materials in the field of display lighting and energy production due to their excellent photoelectric properties.Perovskite light-emitting diodes(PeLED)have developed rapidly in recent years.The current best-performing PeLEDs are based on lead halide materials,but lead toxicity severely limits their practical applications.At the same time,due to the inevitable separation of halogen ions in the mixed halide perovskite under high bias voltage,the light emission spectrum of the device is prone to change,and the metal halide LED with white light emission is still very challenging.In view of this difficulty,the main research object of this paper is a warm white light emitting metal halide LED based on self-trapped domain excitons.Specifically,we optimized the device performance of the LED prepared based on the non-lead metal halide CsCu2I3 material from the three aspects of the hole transport layer,the concentration of the perovskite precursor,and the organic additives.The self-trapped exciton emission peak is located at 575nm,the half-peak width is 134nm,which corresponds to warm white light emission.The final device achieved an external quantum efficiency of 0.47%,and achieved a maximum brightness of 484 cd/m2 at a low voltage of 4.6V.It shows the huge application prospects of this type of solution-processable non-lead halide perovskite materials in white light PeLED devices.In addition,we also set up two sets of related LED efficiency test systems in the laboratory for LED device testing problems.By testing the prepared quasi-two-dimensional green PeLED,it is proved that it can effectively complete the electrical performance characterization of the LED.The optimized quasi-two-dimensional green PeLED device achieves an external quantum efficiency of 7.1%and a maximum brightness of 6800cd/m2.