Preparation And Photovoltaic Performance Of Sulfide Heterojunctions

The forms of solar utilization include thermal energy, biochemical energy, mechanical energy and optical energy. Making use of solar photovoltaic effect to generate electricity, which is known as solar cell, is one of the main ways to use solar energy. However, the development of solar cells is restricted in many aspects at present, such as complex production process of raw materials, and high energy consumption, high production costs, and so on. The key of the solar cell research is preparation of new semiconductor materials with excellent optical properties, by using low-temperature, environmental benignity, low-cost and low-energy-consumption methods. In this paper, the preparation of sulfide heterojunctions was studied and further to be applied to thin film solar cells, and the performance parameters of the battery device was tested at last. The main contents of this paper were summarized as follows:(1) Cadmium metal was sputtered and the CdS nanostructure films on FTO conductive glass substrate were synthetised by simple chemical vapor deposition. Then through ultrasound-assisted, CdS/Ag2S heterojunctions were prepared by ion exchange at room temperature. The effect of different reaction time on the product of the films was detailedly analyzed and a series of characterization and photoelectric performance tests were made. Experimental results show that CdS/Ag2S heterojunction films were dense and composed of nanoparticles with size between 200～400 nm. Films exhibited enhanced visible light absorption and 2.3 times photocurrent response than the pure CdS films with 30.0 μAcm-2 photocurrent density. Inorganic-organic solar cells were assembled with hybridization of CdS/Ag2S heterojunction and P3HT. The parameters of above battery device were followed: an open circuit voltage (Voc) of 0.082 V, a short circuit current density (Jsc) of 0.192 mAcm-2, a fill factor (FF) of 0.261 and power conversion efficiency(PCE) of 0.0046%, which was 2.4 times than CdS film.(2) Tin metal was sputtered and the SnS2 nanostructure films on FTO conductive glass substrate were synthetised by simple chemical vapor deposition. Then tin films with different thickness were purtted on SnS2 nanostructure films and the SnS2/SnS p-n heterojunctions were prepared by high-temperature solid phase reaction. Experimental results show that SnS2/SnS heterojunction films exhibited a dense and uniform morphology, enhanced visible light absorption between 300～1000 nm and stronger photocurrent response. The p-n junction solar cells were assembled and the parameters of above battery device were followed:an open circuit voltage (Voc) of 0.159 V, a short circuit current density (Jsc) of 0.216 mAcm-2, a fill factor (FF) of 0.17 and power conversion efficiency(PCE) of 0.006%. We get better conversion efficiency of 0.011%by preliminary optimizing devices.(3) The CdS/CuS heterojunctions were also prepared by ion exchange. The reaction temperature and reaction time were regulated and controled at 40℃ and 40 min respectively, preparing a dense and uniform CdS/CuS heterojunction films. Through a series of characterization and photoelectric performance tests, the results show that the photocurrent density of CdS/CuS heterojunction was up to 25.0 μAcm-2, which was 2 times than CdS film.