Study On Synthesis And Performance Of New Generation CuInSe₂ Thin Film Solar Cell

For the sake of environmental protection and sustainable development, it is urgent to find clean and cheap renewable energy sources for human being. Solar energy is a promising energy with clean, safe, pollution-free, abundant sources. So far among many kinds of photovoltaic absorb materials, CuInSe₂ (CIS) is a hot topic in solar cell field for its high performances, such as direct and tunable energy band gap, extraordinarily high absorption coefficient, long-term stability and high conversion efficiency. Evaporation, sputtering and electrodeposition are three primary methods for CuInSe2 preparation. Among them, eletrodeposition has attracted much attention because of its low cost, low temperature preparation, large area and continuous processing.In our work, CIS thin film was fabricated through electro-deposition method. The effects of the processing parameters on the material properties were investigated. The optimal experimental conditions of preparing good crystallinity and stoichiometry CIS thin films are obtained as follows: the electrolyte component of 5mmol/L CuCl₂, 30mmol/L InCl₃, 8mmol/L SeO₂, 100mmol/L KCl, 100mmol/L citrate; potentiostatic electrodeposition at the rang of -0.58V～-0.65V(vs. SCE) for 30 minutes; then annealing in 95%(vol) Ar₂ and 5%(vol) H₂ atmosphere at 400℃ for 60 minutes. The structure, morphology, composition and optical properties of CIS thin films were characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Introduced coupled plasma (ICP), scanning electron microscopy (SEM) and UV-VIS etc.The CdS buffer material was fabricated on the CIS surface by Chemical Bath Deposition (CBD). Then the Ti/Au contacts were evaporated to fabricate CIS thin film solar cells. The cells were tested in a standard solar spectrum AM 1.5 instrument. And the average conversion efficiency was 0.47%. The possible reasons for the low conversion efficiency were briefly analyzed.The results show that uniform, compact, chalcopyrite type and near stoichimetry CIS thin film can be prepared by electrodeposition via precisely selected processing parameters. In order to obtain the CIS solar cells with high conversion efficiency, it is necessary to research on the preparation technology of other layers and related factors except for the precise control ED-CIS process.