Synthesis Of CsPbI₃ Perovskite Nanocrystals And Its Application In Light-Emitting Diodes

In recent years,metal halide perovskite nanocrystals（NCs）have been favored by many researchers due to their unique properties including long carrier diffusion length,high carrier mobility,tunable emission wavelength,and narrow full width at half maximum,making them great application potentials in the field of display and light emitting.The photoluminescence quantum yields of perovskite NCs are nearly 100%,and the device efficiency of perovskite NC-based light-emitting diodes（LEDs）has been improved significantly from below 0.1%to over 20%.Among them,all-inorganic perovskite NCs have better thermal stability than organic-inorganic hybrid perovskite NCs,so they are more suitable as alternative materials for preparing efficient and stable LEDs.In the past research,green LEDs have been studied more extensively,and the device efficiency is better than that of red and blue LEDs.Therefore,corresponding to the application requirements of light emitting and display,the device efficiency of the latter two needs to be improved urgently.Based on this,this article focuses on the research of red Cs Pb I₃ LEDs.With the goal of improving device performance,solutions were proposed from the aspect of device structure design,related research was carried out,and more ideal research results were obtained.By innovatively mixing the Zn O electron transport layer with Ti₃C₂ material,the energy level structure of Zn O is changed.Through UPS（ultraviolet photoelectron spectroscopy）research,it is found that with the increase of Ti₃C₂ addition,the overall energy of the electron transport layer will move down,which gradually reduces the injection of electrons.The reason for this is that in the previous structure,the electron injection capability is stronger,which causes electrons to accumulate at the interface,thereby reducing device efficiency.In this way,after adding a certain amount of Ti₃C₂,the injection of electrons will be balanced with holes,which reduces the accumulation of carriers at the interface and increases the balance of carrier transport,thereby achieving a high external quantum（EQE）of 17.4%.