Study On The Inorganic Perovskite And Diamond Films Optoelectronic Devices

Nowadays,the popular organic-inorganic hybrid perovskite solar cells have received unprecedented attention and vigorous development.The photoelectric conversion efficiency of the new solar cell was first applied to photovoltaic devices in Kojima research group in 2009,and now the rate has been as high as22.1%.However the poor stability in high temperature or atmospheric environment seriously restricts its commercialization.The main reason is the organic cations contained in the lead halide framework of organic-inorganic hybrid perovskite materials,such as methyl ammonium?MA?and methamine?FA?,which are unstable,volatile and hygroscopic in the environment,and make the Perovskite film decomposed.Studies have shown that inorganic Cs ions can replace organic cations to enhance their stability in environment or temperature.Therefore,the photoelectric device based on the preparation of CsPbBr₃ films,stability and bandgap control were studied.In addition,a diamond deep ultraviolet photodetector was prepared and its photoelectric properties were studied.The major content is as follows:1.The inorganic CsPbBr₃ thin film was prepared by two-step continuous deposition method.The effects of solvent,hot air assist,soaking reaction time,annealing temperature and annealing time on the properties of the thin film were optimized to improve the compactness of the thin film.Films were prepared on different substrates of mesoporous TiO₂,ZnO nanorods and compact TiO₂,and a planar structure inorganic CsPbBr₃ perovskite solar cell was fabricated with a photoelectric conversion efficiency of 2.3%.2.The environmental stability and temperature stability of inorganic CsPbBr₃thin films were studied.Compared to organic MAPbBr₃,inorganic CsPbBr₃remained stable in the atmosphere for a month,and the structure was still stable after heat treatment at 200?.The influence of different precursors of PbBr₂ and PbI₂ on the doping of thin films was investigated.It was shown that the CsPbI_xBr_3-x thin films with continuously adjustable band gaps can be prepared using PbBr₂ precursor,and the stability is good.3.A diamond deep ultraviolet photodetector was fabricated by photolithography on homo-epitaxial single crystal diamond.Under the irradiation of 213nm wavelength laser,the bias voltage of 30 V,the photocurrent and dark current ratio of the diamond photodetector were as high as 10⁸,the external quantum efficiency was 75.6,and the responsivity was 13 A/W.The effect of annealing temperature on the performance of the detector was studied.After high temperature annealing in Ar atmosphere,the dark current was reduced by about 4orders of magnitude,and the electrodes were in good contact with ohmic linear contact.