Application Of All-inorganic Perovskite Based On Vacuum Thermal Evaporation In Light Emitting Device

Perovskite materials have become a research hotspot in recent years because of their high energy conversion efficiency,high carrier mobility,spectral adjustability and low cost.Research on organic-inorganic hybrid perovskite materials has developed rapidly in recent years.However,the most serious problem of organic-inorganic hybrid perovskite?such as MAPbBr₃,MA=CH₃NH₃?is the very low decomposition temperature.Perovskite is easily decomposed into organic halides and lead halides at high temperatures.In addition,it is very sensitive to water and can easily be eroded by water in normal environment,which limits its future research and application.Therefore,all inorganic perovskite is considered as a feasible method to solve the above problems due to its excellent stability.In this paper,all-inorganic perovskite material CsPbBr₃ was used as a light-emitting material in perovskite light-emitting devices and a charge-generating layer in tandem organic light-emitting devices through vacuum thermal evaporation,respectively.And both of them have achieved good results.The details are as follows:1.We fabricate high-performance green light Perovskite Light-Emitting Device?PeLED?based on all-inorganic perovskite material CsPbBr₃ as light-emitting layer.Firstly,the effect of evaporation rate on the surface roughness of perovskite film is investigated.Through adjusting the co-evaporation rate of two perovskite precursor materials,the influence of film formation process on film formation is analyzed from the perspective of film growth mode.In addition,through measure the performance of light-emitting devices,the effect of the morphology of the perovskite film prepared by evaporation on PeLED is studied in depth,so that the performance of PeLED is significantly improved.The PeLED has a very low turn-on voltage of 2.3 V,and achieves a maximum efficiency of 7.8 cd/A at around 4 V.Besides,when the voltage is 6.5V,the device get maximum luminance of 15450 cd/m².2.The all-inorganic perovskite CsPbBr₃ and n-type semiconductor C₆₀ are stacked to form a new Charge Generation Layer?CGL?.Applying the CGL to inverted structure devices,obvious current response can be observed.The performance of CGL with different thickness has been tested.It is found that increasing the thickness of CGL will affect the charge extraction,resulting in a decrease of current.Besides,the transmittance of visible light is significantly reduced at the same time.After that,it is applied to the tandem Organic Light-Emitting Device?OLED?.Compared with the single-emitter device,the performance of the tandem device is significantly improved.The maximum current efficiency is 2.1 times of that of the single-emitter device,and the luminance at the same current density is also more than twice that of the single-emitter device.At the same time,the external quantum efficiency is also improved to a certain extent.In order to explore the performance of the CGL in other color light-emitting devices,it is applied to a yellow light tandem device.By comparison with the blue light device,the reason for the difference in performance between the two devices is analyzed.