Photoelectric Properties Of Organic-Inorganic Hybrid Halide Perovskite Thin Films And Their Application In LED

Organic-inorganic compound perovskite materials have attracted much attention due to their superior optoelectronic properties,such as long carrier diffusion length,high absorption coefficient and carrier mobility,which have a rapid development in the field of perovskite solar cells.On the other hand,direct bandgap,tunable bandgap,as well as high color purity have enabled perovskite materials to be regarded in the application of light-emitting diodes?LEDs?.At present,the problems based on poor surface morphology,high trap density and low exciton binding energy still limit the imprvoment of perovskite LED devices efficiencies.In this paper,we carried out the research on the material of CH₃NH₃PbBr₃.Firstly,the influence of perovskite morphology,crystallization,photoluminescence?PL?intensity and defects with green anti-solvent ethal acetate?EA?was carried out.Secondly,we fabricated quasi-two-dimensional CH₃NH₃PbBr₃ films by introducing PEA⁺to improve exciton binding energy.And then we carried out the influence of crystallinity orientation,and defect densities based on these perovskite films via different annealing temperatures treatment.With optimizing the transport layers,the LED device with higher efficiency were fabricated.The results of the study obtained are as follows:?1?Here,green antisolvent ethyl acetate?EA?was introduced to improve the quality of CH₃NH₃PbBr₃ perovskite films via films formation process.Compared with traditional antisolvents of high toxicity,toluene?Tol?and chlorobenzene?CB?,EA had the lowest boiling points and highest polarity,which could completely extract DMF and DMSO from perovskite films.The perovskite films with increased crystallinity,reduced Pb⁰ defects and enhanced PL intensity were fabricated.With these benefits,The maximum luminance,current efficiency?CE?and external quantum efficiency?EQE?of EA-LED are 13883 cd/m²,6.72 cd/A and 1.44%,showed about 200%and 100%boosts in EQE compared with Tol-LED and CB-LED.?2?The PEABr was introduced into the CH₃NH₃PbBr₃ preursor solutions to obtain quasi-two-dimensional structure and improve the exciton recombination.It was found that the crystallinity orientation of perovskite films with different annealing temperatures treatment was significantly influenced.The sample with 120°C annealing showed the best crystallinity orientation,which significantly reduced the film defects.Compared with the sample with no annealing,the PLQY of perovskite films was improved from 13.8%to 56.7%and lifetime was increased from 9.50 ns to 26.12 ns,respectively.The LED devices based on these films possessed the biggest CE and EQE,which are 27.08 cd/A and 6.86%.