The Application Of Antireflective Film With Micro/Nano-structure In Solar Cells

Solar energy is considered one of the most promising renewable energy sources due to its advantage in alleviating the current energy crisis and environmental pollution.Solar cell can directly convert sunlight into electrical energy,but it is not widely applied at present,the major reason is too high production cost and too low conversion efficiency for solar cell.Therefore,improving conversion efficiency and reducing production cost of solar cell are the main goal of the research in the future research.However,the application of micro/nano-structure antireflective film can greatly reduce the reflective of light on the front surface of solar cell,thereby improving the photoelectric conversion efficiency of solar cell.Therefore,it is of great important significance that the research and application of the micro/nano-structure reflective film in the solar photovoltaic industry.In this thesis,several different anti-reflection films are designed and fabricated for silicon solar cells according to different methods and processes.These antireflection films can reduce the reflection loss on the surface of solar cells and improve the efficiency of solar cells.The details are as follows:The first chapter introduces the research background and significance of solar energy industry and the research status of solar cell antireflection film at home and abroad.The second chapter introduces the theoretical basis of the antireflection.First,the basic principle of antireflection film is introduced.Secondly,the analytical theory of antireflection film for planar structure and micro/nano-structure was introduced,as well as several methods for fabricating antireflection film.In the third chapter,the parabolic microlens array with high packing density and high aspect ratio is fabricated by using the method of direct writing with UV laser beam.Then,the PMLA is transferred into the surface of silicon solar cells by soft imprint lithography method,the interfacial reflection loss of solar cell can be reduced from 7.03%to 2.96%,thereby the photoelectric conversion efficiency of the silicon solar cell can be increased from 16.7%to 17.7%.And the water contact angle of solar cell is increased from 98.2° to 154.8°,therefore,the hydrophobicity of solar cell is significantly enhanced,and the dynamic contact angle further shows that this structure also has the ability to improve the solar cell self-cleaning.In the fourth chapter,the surface modulations method was proposed to modify the surface of the flexible material under tension,and then release the tensile force to restore the original length,the surface will spontaneously produce similar winkle of nanostructures.This fabrication process is simple and inexpensive.And this kind of nanostructured flexible material can adhere to the surface of solar cells encapsulated by epoxy resin.The results show that this nanostructure can reduce the reflection loss of the upper surface of the solar cell and improve the efficiency of the solar cell.In the fifth chapter,a soft-imprinting method is proposed to fabricate a multi-scale structure with a nano-nipple array structure on a millimeter lens array.This structure is transferred to the surface of the solar cell,which can achieve low-intensity focusing of sunlight and reduction of solar reflection at the interface of the array cylindrical mirror,resulting in the photoelectric conversion efficiency of the silicon solar cell increasing from 14.1%to 15.8%.And the water droplet contact angle on the surface of solar cell was increased from 82° to 144°,which significantly improved the hydrophobicity of the battery.The sixth chapter summarizes and prospects the work of this thesis.