Study On Fabrication And Thermal Insulating Properties Of IR-filting Films By Magnetron Sputtering

In the last few years,with the increase of population,more and more energy resources are demanded.Solar energy has become the favor of people as well as the researchers as a kind of non-toxic,pollution-free and renewable energy resource.How to increase the efficiency of solar cells has drawn public concern.Efficiency of solar cells can be mainly affected by temperature,light intensity and structures of solar cells.The highest efficiency of silicon solar cells has reached 26.6% in 2017.However,there are ways to improve the efficiency of solar cells such as improving the cooling rate of backplane material and covering the solar cell with anti-reflection coatings to increase light intensity.In this thesis,a lot of work has been done to prepare IR-cutting films which have high transmittance in the wavelength range of 380-1100 nm while low transmittance in 1100~2500 nm.The films are aimed to be used as solar-cell covering materials to avoid the infrared thermal effect which leads to temperature growing up and efficiency decrease of solar cells.Firstly,different AZO films were prepared by magnetron sputtering on glass substrates with different Ar flow rates,sputtering pressure and heat treatment.The AZO film sputtered with 10 sccm Ar at room temperature had transmittance over 88% in 380~1100 nm,and had transmittance of only29.70% at 2500 nm.The temperature rise of the solar cell was reduced by 3.12 ?C and the decreament of the open circuit voltage was decreased by 1.10%..Secondly,in order to lower the transmittance of films in near infrared region(1100~2500 nm),the AZO/Metal/AZO structure was chosen.The FDTD solution was used to simulate the transmittance of different metal films such as Cu,Ag and Au mono-layers with different thickness.AZO/Cu/AZO films was produced according to simulation results by RF magnetron sputtering.The temperature of the solar cell covered with this AZO(139.70 nm)/Cu(9.36 nm)/AZO(139.70 nm)film was reduced by10.61 ?C and the decreament of the open circuit voltage was decreased by 5.41%.Finally,as Cu is directly contact with AZO in AZO/Cu/AZO structure,AlN was added between Cu and AZO layers to protect Cu from being oxidized.The AZO/AlN/Cu/AlN/AZO films with different Cu-layer thickness were prepared by magnetron sputtering.The results showed that AlN prevented the mutual diffusion of Cu and AZO layers.And with the increase of Cu-layer thickness,transmittance of multilayers decreased in 1100~2500 nm,the AZO/AlN/Cu(14.04 nm)/AlN/AZO hadtransmittance of 59.78% in 380~1100 nm,8.53% at 2500 nm.The AZO/AlN/Cu(10.53 nm)/AlN/AZO had transmittance of 63.26% in 380~1100 nm,13.24% at 2500 nm.The temperature rise of the solar cell was reduced by 12.75 ?C in 3.5 h and the decreament of open circuit voltage decreased by 6.61%when covering the solar cell with this multilayer.