Controllable Synthesis,Doping And Physical Properties Of Alkaline Earth Metal Stannate Perovskite Thin Film

As a new thin film solar cell,perovskite solar cell has been a research hotspot in the field of new solar cells for the advantages of its high photoelectric conversion efficiency and low cost.At present,the absorbability of perovskite solar cells is still dominated by organic-inorganic complex halogen perovskite materials?methylamine lead iodine:CH₃NH₃PbI₃?,which is highly sensitive to environmental water and greatly limits the application of perovskite solar cells for its potential environmental toxicity.It is of great significance to develop an all inorganic perovskite optical absorption material with narrow band gap and high stability.Alkaline earth stannate is a typical perovskite oxide material.It has the characteristics of prohibition of bandwidth?3.18-4.5 eV?,high resistance and high temperature stability.Meanwhile,it has has been widely studied for its extensive optical,electrical and magnetic properties.In particular,the property of adjustable band gap makes it very suitable for the light absorption materials of the perovskite solar cells.However,there are no reports in this field at present.This paper focuses on the preparation of metal doped alkaline earth tin stannate film,and the influence of elemental doping on the structure,optical/electrical/magnetic properties,so as to lay the foundation for its application in perovskite solar cell devices.Main research achievements are as follows:?1?Controllable preparation and physical properties of Co-doping SrSnO₃ thin films:It was applied to grow SrSn_1-xCo_xO₃ thin films on MgO substrates by pulsed laser deposition method,and the effects of Co doping on microstructure,morphology and optical,electrical and magnetic properties of SrSn_1-xCo_xO₃ films were investigated.The results showed that the SrSn_1-xCo_xO₃ thin films prepared by pulsed laser deposition method were epitaxial thin film?100?along the growth direction.It was proved that the SrSn_1-xCo_xO₃ thin films with smooth surface and dense were tetragonal symmetry structure through?scanning;the roughness of the SrSn_1-xCo_xO₃ thin films increased with the content of Co-doping.In the range of 200 nm to 800 nm wavelength,with the increase of Co-doping content,the optical transmittance of the films were reduced from95%to 56%,and the optical band gap reduced from 4.46eV to 2.91 eV.Moreover,the dielectric and magnetic properties of the films were characterized.The dielectric constant of the SrSn_1-xCo_xO₃ films reached 213.17?10 KHz,room temperature?,and it exhibited obvious ferromagnetic properties at room temperature.The saturation magnetization increased with the increase of Co-doping content from 2.38 emu/g to12.49emu/g.?2?The preparation and physical properties of Co-doping BaSnO₃ thin films:The BaSn_1-xCo_xO₃ thin films were grown on MgO substrates by pulsed laser deposition method.The effects of Co-doping on the microstructure,morphology and optical properties of the BaSn_1-xCo_xO₃ thin films were investigated.The results showed that the BaSn_1-xCo_xO₃ thin films prepared by pulsed laser deposition method were epitaxial thin film?100?along the growth direction.It was proved that the BaSn_1-xCo_xO₃ thin films with smooth surface and dense were tetragonal symmetry structure through?scanning;the thickness of the BaSn_1-xCo_xO₃ thin films was about 210nm and the roughness increased with the content of Co-doping.In the wavelength range of 200 nm to 800nm,with the increase of Co-doping content,the optical transmittance of the films decreased from 97%to 72%,and the optical band gap decreased from 3.23 eV to 2.31eV.Meanwhile,the effects of Co-doping content on the photoelectric properties of the BaSn_1-xCo_xO₃ thin films were studied.The J-V curves of BaSn_0.65Co_0.35O₃ films were similar to batteries,and the short-circuit current(J_sc)and the open circuit voltage(V_oc)were to 5.57 mA/cm² and 0.17 V,which laid the foundation for its application in the device of the perovskite solar cells.