Electroluminescent Device Based On Hybrid Perovskite Material

The perovskite material based on ABX₃ has attracted the attention of many researchers due to its excellent photoelectric properties.These advantages include high charge carrier mobility,high PLQY,and solution processability.Perovskite solar cells already have an efficiency of 23.7%,which is comparable to photovoltaic cells made from traditional inorganic semiconductor materials.And they are also used as effective low threshold gain media in optical pump lasers.At the same time,the perovskite material also has the advantages of easy adjustment of luminescent color and high color purity.The excellent electrical and optical properties of perovskite materials make them ideal for a new generation of large-area,high-performance optoelectronic devices.And perovskites are rich in materials and low in price,so perovskite electroluminescent devices has a high value in light-emitting diodes?LEDs?for display and illumination.In this study,we mixed the all-inorganic perovskite solution with the polymer solution PAN?polyacrylonitrile?in a volume ratio of 1.5:1 to obtain a perovskite:polymer mixed solution and we obtained a high-coverage,dense and uniform mixed perovskite film by one-step spin coating method,and prepared a perovskite electroluminescent device with a mixed film as a luminescent layer.We prepared two color PeLEDs with the following structure:?1?ITO/Pedot:PSS/PAN:CsPbBr₃/TPBi/Liq/Al?Green??2?ITO/Pedot:PSS/PAN:CsPbBr_2.5I_0.5/TPBi/Liq/Al?Red?The green perovskite electroluminescent device has a maximum luminance of2300 cd/m² at 7.5 V,a maximum efficiency of 5.07 cd/A and the peak intensity of EL spectra is at 520 nm.The maximum luminance of the red perovskite electroluminescent device at 8V is 657 cd/m²,and the peak intensity of EL spectra is at 680 nm.We found that the hybrid film with PAN showed higher coverage,the number of pinholes was significantly reduced and the performance of the two sets of devices is significantly improved relative to the polymer-free perovskite electroluminescent device.In addition,we fabricated white PeLED using the perovskite–polymer mixed material PAN:CsPbBr_2.5I_0.5,pure inorganic perovskite CsPbBr₃ and organic small molecule material NPB as the luminescent layer.The structure of the device is ITO/PEDOT:PSS/CsPbBr_2.5I_0.5/NPB/CsPbBr₃/TPBi/Liq/Al,wherein the CsPbBr_2.5I_0.5 film was obtained by one-step spin coating,and the CsPbBr₃film was obtained by dual source co-evaporation.The maximum luminance of the device at 7V is 360cd/m² and the efficiency is 0.2cd/A.The color coordinate of white PeLED is?0.31,0.36?,which provides a new idea for the development of white PeLED.