Preparation Of All-inorganic Perovskite Quantum Dots LED Devices

In recent years,perovskite quantum dots have attracted extensive attention due to their superior optoelectronic properties.All-inorganic perovskite quantum dot CsPbX3(X=Cl,Br,I)has high quantum yield.The characters of narrow half-peak width,high color purity,wide color gamut and low energy consumption making it become the core materials of the new generation of quantum dot display technology(QLED).However,there are still some shortcomings such as poor surface ligands and low perovskite films qualities.In this thesis,different wavelengths of perovskite quantum dot LED devices were fabricated and the surface ligands of QD were studied.The effect of ligand amounts and the quality of the perovskite films were also studied.The main content of the thesis is as follows:(1)The all-inorganic perovskite quantum dots were synthesized via thermal injection,and the total inorganic perovskite quantum dots CsPbX3(X=Cl,Br,I)were adjusted in the visible range(400-700 nm)by adjusting of halogen atoms.Three kinds of all-inorganic perovskite quantum dot LED devices with red,green and blue wavelengths of 692 nm,516 nnm and 408 nm were achieved,which can help the application of all-inorganic perovskite LEDs in the field of white light illumination.(2)The effects of surface ligand density,concentration of quantum dot,annealing temperatures and the performance parameters of the LED were investigated.It was found that when keep ligand cleaning times as 2,the quantum dots concentration is 20 mg/ml,and the annealing temperature is 20 ?,we got optimized LED performance.(3)The CsPbBr3 films prepared by one-step method were used to prepare perovskite luminescent layer with full coverage,high compactness and low roughness by doping PEO.The PEO concentration was investigated.The effect of the surface morphology,the performance of the LED device,and the experimental results were analyzed from the viewpoints of fluorescence intensity,film quality,fluorescence lifetime and it was found that when the concentration of PEO keep as 10 mg/ml,we can get optimal quality of the perovskite film and the performance of LED.The maximum brightness and external quantum efficiency are 1223 cd/m2 and 0.26%,respectively,moreover performance is up to 5 times than devices without PEO.