Preparation And Characterization Of Crystal Silicon Solar Cells Based On Tungsten Oxide

With the development of the times,energy consumption is getting faster and faster,and the development of new energy is an eternal topic.Crystalline silicon solar cells have mature preparation processes,good stability,and good cost performance.In recent years,non-doped materials such as transition metal oxides,alkali metal compounds,and small organic semiconductor molecules have become more and more popular among scientific researchers.These materials can be used to prepare thin films by thermal evaporation,sputtering deposition,atomic layer deposition,and solution processing.At the same time,these molecules can not only form heterojunctions with crystalline silicon,but also serve as selective contact layers for electrons or holes in solar cells..While the cost is low,the process is relatively simple.This paper starts from transition metal oxide materials,prepares high-efficiency solar cells,and studies the photovoltaic performance of the cells.The main work of the thesis includes:(1)Using thermal evaporation process to prepare tungsten oxide(WO_x)thin film,contact with the back of n-type crystalline silicon to form heterojunction solar cells.Changing different back contact electrodes and exploring the impact on cell performance confirmed that the WO_x/Ag structure can effectively improve the battery performance,achieving an efficiency of 15.1%.The J-V-T test of the battery shows that the carrier transmission is minority carrier tunneling at low pressure,and multiple carrier thermal emission at high pressure.The use of Sun-Voc test shows that improving the series resistance effect of the battery can further increase its efficiency to 17.2%.The temperature change test shows that the n-type crystalline silicon/WOx/Ag structure has an excellent temperature coefficient.Compared with the traditional crystalline silicon battery,the temperature is significantly reduced to a temperature coefficient of-0.35%/K for photoelectric conversion.The performance of traditional batteries is reduced by 22%due to temperature.(2)A diffusion layer was prepared by doping phosphorous(P)on the surface of the P-type crystalline silicon,and a WO_x film was prepared on the back of the P-type silicon using a thermal evaporation process as a hole-selective contact layer,and a photoelectric conversion efficiency of 16.5%was obtained.At the same time,comparing the effects of different metal electrodes on the battery,WO_x/Ag back contact can obtain a lower contact resistivity of 30 mΩ·cm2,and its short-circuit current density reaches 37.36 m A/cm~2,indicating that WO_x acts as a carrier The potential for selective passivation of the contact layer.At the same time,the performance of the p-type crystalline silicon cell is improved by changing the thickness of WO_x.When the thickness is 10nm,the cell efficiency reaches 17.1%,and its series resistance is only 1.73Ω·cm~2.