Preparation And Study Of Luminescence Properties Of CsPbCl₃ Perovskite Thin Films Based On Silicon Substrate

Halogen perovskites have unique optical properties such as high absorption coefficient,adjustable band gap,minimal Stokes shift,high charge carrier mobility,long diffusion length and low trap density.It has a wide range of applications in the fields of solar cells,light-emitting diodes,and lasers.The all-inorganic perovskite CsPbCl3 is a direct band gap semiconductor with a wide band gap of 3 eV.The exciton binding energy is 75 meV.It has exciter emission at room temperature and has high luminous efficiency.CsPbCl3 has a very broad application prospect in lasers,photodetectors,luminescence and other fields.However,there are still few studies on the luminescence properties of CsPbCl3 thin films.In this paper,CsPbCl3 thin films were prepared on silicon substrate by thermal evaporation.The photoluminescence(PL)properties of the film were studied.And the CsPbCl3 blue electroluminescent(EL)devices were prepared,which may provide a new idea for the study of silicon-based blue EL.The main contents and results of this paper are as follows:(1)Study on the properties of CsPbCl3 crystal.The CsPbCl3 crystal was successfully prepared by the melt method.The crystal belongs to the tetragonal structure,the PL emission peak is at 410 nm,and the full width of half maximum(FWHM)is 13 nm.The CsPb(Cl/Br)3 crystal was obtained by changing the ratio of halogen.The luminescence and crystallization properties of the prepared crystals were characterized.The results show that with the incorporation of Br,the luminescence and XRD diffraction peaks of the crystals move toward the luminescence and diffraction peaks of CsPbBr3.The regulations of the halogen ratio to the luminescence of halide perovskites are verified.(2)Study on the properties of CsPbCl3 thin film.The CsPbCl3 thin films were deposited on the silicon substrate by thermal evaporation,and the blue-violet PL was obtained.The luminescence emission peak is at 410 nm and the FWHM is 13 nm.The film had obvious preferred orientation of(002)direction.The effects of substrate temperatures,annealing temperatures and annealing time on the PL emission and crystallization were investigated.The results show that the thin films had a better luminescence performance when prepared at the substrate temperature of 150℃ and annealed at 450℃ for 60 s.In addition,the PL stability of CsPbCl3 film was also analyzed and tested.(3)Preliminary investigation of all-inorganic CsPbCl3 thin films blue EL device.NiO was chosen as the hole transport layer.A multilayer all-inorganic blue EL device was prepared by magnetron sputtering and thermal evaporation.The device has a typical rectification behavior with turn-on voltage of approximately 3 V,and the blue EL of CsPbCl3 is obtained.