| CIS thin films solar cell is a solar cell with good prospect featuring in high conversion efficiency, low cost and stable structure. CuInS2 belongs to the direct band gap semiconductor materials with a high absorption coefficient, though it can be used as one of the best thin film solar cell absorption layer material; ZnS is considered to be the most ideal material for buffer layer with these features:non-toxic, low cost, band gap wider than the CdS which is widely used, and higher lattice matching degrees with CIS (CIGS).In this paper, with the CuInS2 nanopowders, prepared by hydrothermal method and the ZnS and CuInS2 films prepared by hydrothermal chemical co-reduction, the influence of different raw material, solvent, temperature and holding time was studied on the phase, surface morphology, electrical performance of the target product. The prepared products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and four probe tester. The main work and conclusions are as follows:(1) In the hydrothermal method, different reactants have its own reaction mechanism. Ethanol, hydrazine hydrate and ethanol solvent were respectively used in the successful preparation of wurtzite structure CuInS2 and chalcopyrite structure CuInS2 powders. The influence of the different raw materials, temperature and holding time is mainly analyzed on these two kinds of the phase and morphology of crystal structures. From the microscopic perspective, wurtzite structure CuInS2 were circular particles with diameter of 0.1-0.3 μm; Chalcopyrite structure CuInS2 filaments were filaments reunion; with different reactants comparison adopted, it is found that it is more suitable to prepare the wurtzite structure CuInS2 with CuCl2·2H2O, InCl3, SC(NH2)2as raw material, which has best degree of crystallinity in highest diffraction peak intensity with condition of 160℃ for 20 hours; in the preparation of chalcopyrite structure CuInS2, the results show that the increase of temperature and time is advantageous for the synthesis of the target product.(2) The ZnS thin films were prepared by hydrothermal chemical co-reduction and it was to analyze the influence of different solvent, zinc source, temperature, holding time and numbers of coating on the preparation of ZnS thin films. What is found out is that it is easier to obtain the target product with ethanol as the solvent, ZnO as source of zinc. Between 140～180℃, with the increasing of temperature, ZnS diffraction peak enhanced, with better crystallization; with the temperatures continue increasing, it appears impurity ZnO; under the condition of 180℃ for 20 hours, perfect crystal structure and pure phase of ZnS is found out. From the microscopic perspective, ZnS appears mostly like a ball with 1μm diameter; the reaction time had a great influence on synthetic product; with the number of coating increased, the diffraction peak intensity is enhanced and crystallization becomes better.(3) The GuInS2 thin films were prepared by hydrothermal chemical co-reduction, respectively with chloride (indium chloride, copper chloride) and nitrate (copper nitrate, nitric acid indium) as materials. When adopting the chloride as raw materials, glass and silicon two different substrates were used, it was found that they tend to generate NaCl and NH4Cl impurities respectively, which can be removed by soaking; by changing the number of coating, the impurities can not be eliminated and has little influence on the characteristic peak. When nitrate was adopted as raw materials, with the temperature increasing between 140～220℃, impurity peak CuS disappears, and Na(NO3) impurity peak appears at 220℃, but the characteristic peak of CuInS2 is very clear, while impurity peak Na(N03) can be removed easily through soaking; at 220℃, with the heating time extended, the CuS impurity peak appears. Whereas, the extension of heating time doesn’t play a good role on synthesizing CuInS2; different raw material to synthesis the CuInS2 thin film has different best conditions. With chloride as raw material, the best condition is 220℃ for 20 hours, under microscopic, CuInS2 is globular,0.2～0.5 μm in diameter; nitrate is 220℃ for 10 hours. |
PDF Full Text Request