High Efficiency Selective Emitter Solar Cell Research And Preparation

Currently, the global energy consumption mainly includes coal, oil, gas and other fossil fuels which are harmful to the environment, if uncontrolled exploitation continues, the world will face serious energy threat by mid-21st century. In recent years, the climate in many areas became abnormal, the scope of the acid rain is expanding and the ozone hole is growing bigger, all of these are because of the use of fossil fuels. In order to reduce the air pollution caused by fossil fuels and ensure the long-term energy supply, it is necessary to adopt the sustainable development strategy and accelerate the development of renewable energies, which is already a world-wide consensus. Among the renewable energies, the solar power has become the focus of research and development of many countries due to its many advantages.Crystalline silicon solar cells are the leading one among the solar cells because of its high efficiency and stable performance. High conversion efficiency and low cost always have been the goal of production. Since the crystalline silicon solar cells with the selective emitter can make up for the disadvantage of the ones with the homogeneous emitter and make it possible for further development, they become the focus of new cell research.This paper conducts a theoretical analysis of the selective emitter structure and discusses the advantages and disadvantages of methods of building up the structure. Through process design and optimization, the paper offers three improvement methods in the ordinary production condition, which are firing without ARC and dry etch method,two-step firing and dry/wet etch method and regular firing and dry/wet etch method. During the experiment, this paper uses a variety of testing methods and equipment to get an accurate analysis result on the experimental conditions and the samples, such as the Four Probe Tester, the Heat-Cool Probe Tester, SRP, Datapaq, Correscan, SEM, EDX and Optical Confocal Microscope. The experiment data are analyzed by Minitab software. By a large number of experiments and data analysis, this paper proves that the improvement methods proposed by the paper is highly feasible in choosing crystalline silicon solar cell with the selective emitter under the existing production condition with obtainable supplementary material. The methods can also increase the conversion efficiency of crystalline silicon solar cell. Furthermore, the paper has developed two-step firing and a corrosion solution which reacts only with the silicon material and not with the aluminum back field as required by the improvement methods.At the same time, this paper also pointed out the direction of future process optimization based on the improvement methods. With the ever updating of production facilities, the continuous improvement of supplementary material and the production process, the methods proposed by the paper will definitely be put into application in the massive production of crystalline silicon solar cells with selective emitter.