Study On The Preparation Of Fluoride Broadband Antireflection Coatings By Magnetron Sputtering

Metal fluoride has low absorption and high light transmittance in a wide wavelength range(0.13?m-12?m),so it is widely used in various photoelectric devices.However,non-stoichiometric fluoride films are easy to be prepared in the fluoride films prepared with magnetron sputtering,which will lead to the phenomenon of fluorine deficiency in the deposited films and reduce the antireflection effect of the films.In this work,SF₆ was used as the reactive gas to suppress the F deficiency defect in the fluoride films with changing the working pressures and sputtering powers.When the working pressure and sputtering power are 1.5 Pa and 150 W,the atomic ratio of F:Al on the surface of AlF₃ film is 2.94:1,which is close to the normal stoichiometric ratio of 3:1;the crystallization property of the film prepared under these conditions is the best.The refractive index in the wavelength range of 300-1100 nm of AlF₃ film is 1.549-1.386;the average transmittance in the wavelength range of 300-1100 nm of AlF₃ coated glass is 94.07%,which is 0.87 percentage points higher than that of uncoated glass 93.2%,making the film have broadband antireflective effect.When the AlF₃ coated glass cover is applied to solar cells,the short-circuit current density reaches 14.510 m A/cm²,which is 2.17%higher than that of the uncoated glass14.202 m A/cm².As a result,the photoelectric conversion efficiency of the solar cell is increased from 27.23%to 27.76%,with a relative improvement of 1.94%.When the working pressure and sputtering power are 2.0 Pa and 185 W,the atomic ratio of F:Ca on the surface of Ca F₂ film is 1.97:1,which is close to the normal stoichiometric ratio of 2:1;the crystallization property of the film prepared under these conditions is the best.The refractive index in the wavelength range of 300-1100 nm of Ca F₂ film is 1.425-1.368;the average transmittance in the wavelength range of 300-1100 nm of Ca F₂ coated glass is 95.13%,which is 1.93 percentage points higher than that of uncoated glass 93.2%,making the film have broadband antireflective effect.When the Ca F₂ coated glass cover is applied to solar cells,the short-circuit current density reaches 14.626 m A/cm²,which is 2.99%higher than that of the uncoated glass14.202 m A/cm².As a result,the photoelectric conversion efficiency of the solar cell was increased from 27.23%to 28.27%,with a relative improvement of 3.81%.