| Energy demand is increasing with the growing of world population. At present, as the main energy source, fossil fuels are not sustainable energy and fossil combustion releases toxic gases which can seriously pollute the environment. Therefore, the search of clean energy sources to replace conventional energy is imminent. Among kinds of new energy sources, solar energy is the most abundant, clean and efficient energy sources. When compared with crystalline silicon, thin film solar cells have many advantages. Film semiconductor thin film material can be prepared by very inexpensive way which can save raw materials, reduce energy consumption, short cycle of feedback use. Moreover, it can be deposited on flexible substrates and can be done directly on a large scale integrated battery assembly. Copper indium gallium selenide (CIGS) thin film is one of the most suitable solar cell absorber layer. However, the content of indium and gallium elements on the earth is not high, which may limit its large-scale commercial application. So in recent years, research and exploration of alternative materials CIGS have caused widespread concern.(â… )2(â…¡)(â…£)(â…¥)4type of quaternary compounds of copper zinc tin sulfur/selenium (CZTS/Se), of which the required elements were relatively abundant and low cost and low toxicity, is considered to be the suitable substituted material. CZTS/Se cell photovoltaic properties is good for high theoretical conversion efficiency. However, there is some loss behavior limits the further improvement of practical conversion efficiency or output efficiency. These losses processes include loss of light absorption, collection of electrons, recombination loss and impedance losses et al.The research subject is to explore the preparation of new materials. At the same time, testing and researching the electrical properties of some cells was carried out for understanding why the photoelectric conversion efficiency of the solar cell is low. Hope to give an effective means through clear characterization of the electrical properties of cells to improve the conversion efficiency. The content of the paper include two main parts:The first part is the preparation of CuInS2and Cu2SnSe3thin film materials. The preparation of CuInS2thin-film absorber layer was based on oxide precursor. Through changing the sulfurization temperature, the high-quality CIS film with good crystallization and single-phase was prepared. The corresponding thin film batteries were also prepared. Despite the absorbing layer crystal structure and appearance are very good films, the CIS thin-film battery is low efficiency. So we are going to expand the study of cell device and analyze the reason why the cell conversion efficiency is not high.The second part describes the physical mechanism of solar cell devices firstly. Then investigate and survey the basic principle of the battery, the equivalent model and several common research tools to investigate the pn junction-based batteries. A series tests were done on thin film solar cells with the structure of SLG/Mo/CZTSe/CdS/ZnO/ZnO:Al. Current-voltage curve analysis gives the value of important parameters, such as ideal factor and reverse saturation currents of the junction et al. Capacitance-voltage test under dark field can deduce the carrier concentration, which has a significant impact on the quality of the battery. Capacitance-voltage test under variable temperature condition was also carried out to research the type and the concentration of defects in the materials. |
PDF Full Text Request