CuSbSe₂Thin Film And Application In Solar Cell Devices

The government and public are putting more and more attention on the solar cells in energy source. Among the various types of solar cell devices, CIGS thin film solar cell is one of the most popular thin film solar cells. But the metals used in CIGS solar cells such as In and Ga are both rare metals, and expensive. This limits the production and application of CIGS solar cells. Thus it’s urgent and meaningful to find some materials to substitute CIGS absorber film in CIGS thin film solar cells, or to find some metals to substitute In and Ga in CIGS.Among the materials to be chosen, CuSbSe2has a lower price and a proper band gap which is about1.06eV and gets some attention. But the research on the method of preparation of CuSbSe2thin film is not enough, and few reports have been published about the fabrication of CuSbSe2thin film devices. In this dissertation, synthesis of high-purified CuSbSe2material, preparation of the CuSbSe2thin film and solar cell device, and performance of the device are studied.The main content of the dissertation is below.1. Synthesis of high pure CuSbSe2materialHigh pure CuSbSe2material is synthesized by solid phase reaction and Bridgman-Stockbarger Method. The fundamental structure and thermal property of CuSbSe2are tested. The melt point of CuSbSe2is478℃.2. Preparation and performance of CuSbSe2thin filmMethod for preparation of CuSbSe2thin film is studied, and the atmosphere, substrate, temperature and time in annealing process are emphasized.CuSbSe2thin film should be annealed in vacuum, for it is sensitive in Se atmosphere. CuSbSe2thin film has a similar expansion coefficient as the Mo and sapphire. The best annealing temperature and time for CuSbSe2thin film are420℃and60min, respectively. The proper rate for temperature change is1℃/min.The crystal grain size of CuSbSe2thin film is between0.6um and1.0um, the resistivity is about160Ω*cm, the carrier concentration is1.1×1016cm-3, the carrier mobility is about1.5cm2/(V*s), the optical absorption coefficient is7～9*104cm-1, and the band gap is1.06eV.3. Fabrication and performance of CuSbSe2thin film devicesCuSbSe2thin film device is fabricated with the common process used in CIGS thin film device fabrication. The conversion efficiency of the device is0.72%, the open-circuit voltage is204mV, the short-circuit current density is12.78mA/cm2, and the fill factor is only27.6%. One of the factors that lead to a poor performance of the device is that we have little experience on the preparation of the films in the devices besides the absorber film. Thus, more emphasis should be put on them.