Temperature-dependent Photoluminescence And Third-order Nonlinear Optical Properties Of Mn²⁺-doped CsPbCl₃ Nanocrystal

Now,perovskite materials has a broad scope of development in light-emitting diodes（LEDs）,light-emitting solar concentrators,lasers and photodetectors and other photoelectric technologies by virtue of their huge advantages such as narrow full width half maximum（FWHM）,tunable broadband gap between near-infrared and visible light regions,and ultra-high photoinduced quantum yield（PLQY）.However,lead halide perovskite is very sensitive to some external conditions,such as ultraviolet,oxygen,water and high temperature,which adds a great obstacle to the extensive application of lead halide perovskite in human life.In order to solve these problems from the source as much as possible,we take three-dimensional all-inorganic perovskite CsPbCl₃nanocrystals（NCs）as the research object,and the transition metal Mn²⁺is selected to doped it.This can optimize or modify the optical properties of CsPbCl₃ NCs by doping as much as possible,reduce the toxicity of Pb²⁺in CsPbCl₃ NCs,and improve the thermal stability of CsPbCl₃ NCs,Finally,the third-order nonlinear optical properties of CsPbCl₃ NCs and Mn:CsPbCl₃ NCs are studied.The main points are as follows:（1）In this paper,monodisperse CsPbCl₃ NCs and Mn:CsPbCl₃ NCs were synthesized by traditional thermal injection method,and the synthesized nanocrystals were centrifugated by fractional centrifugation,so that they had uniform size.The synthesized CsPbCl₃ NCs and Mn:CsPbCl₃ NCs were morphologically characterized using transmission electron microscopy（TEM）,and their crystal phase were also characterized using X-ray diffraction（XRD）.The positive doping of Mn²⁺in CsPbCl₃NCs has been successfully demonstrated through the utilization of X-ray photoelectron spectroscopy（XPS）.And the successful synthesis of Mn:CsPbCl₃NCs has also been verified by energy dispersive X-rays（EDX）.The effects of Mn²⁺with different doping ratios on the optical properties of CsPbCl₃ NCs were studied by UV-visible spectroscopy（UV）and stable fluorescence spectroscopy（PL）.（2）Temperature-dependent photoluminescence（PL）spectra was used to study the photophysical properties of CsPbCl₃ NCs and Mn:CsPbCl₃ NCs in the temperature range of 80～350 K.The study of temperature-dependent PL includes the variation of PL intensity,PL peak position and full width half maximum with temperature,and then the exciton dynamics was studied.（3）The synthetic CsPbCl₃ NCs and Mn:CsPbCl₃ NCs were dispersed in methyl methacrylate（MMA）,which was used to produce CsPbCl₃/PMMA and Mn:CsPbCl₃/PMMA glasses.CsPbCl₃/PMMA and Mn:CsPbCl₃/PMMA OGs was tested by closed-aperture（CA）Z-scan technique and open-aperture（OA）Z-scan technique to investigate its third-order nonlinear optical properties.The CA Z-scan experiment shows that both CsPbCl₃/PMMA and Mn:CsPbCl₃/PMMA are self-focusing media,and the OA Z-scan experiment shows that Mn:CsPbCl₃/PMMA has a higher two-photon absorption coefficient,which is 4.5 times that of CsPbCl₃/PMMA.Mn:CsPbCl₃/PMMA material has high application value in laser protection.