| The intermediate band solar cells have become a hot research issue, because they have many potential advantages, such as high conversion efficiency, simple design and low cost. CuInS2 is a kind of direct band gap semiconductor materials. It has been an ideal thin film solar cell material of the light absorbing layers, because it has many advantages, such as larger absorption coefficient, suitable band gap (1.5eV), high stability and low toxicity. Powder coating method has been used in this experiment. In order to prepare the material for the intermediate band absorption layers, Ce is doped into CuInS2.In our experiments, precursor slurry has been prepared by ball milling method. A series of precursor films were prepared by using prefabricated slurry coating on glass substrate under different speed conditions. Then, a series of CICS films were prepared under different rapid thermal annealing temperatures in Ar atmosphere. High quality films have been characterized by using energy dispersive X-ray spectroscopy (EDS), X ray diffraction (XRD), ultraviolet visible spectrophotometer (UV-VIS-NIR) and X ray photoelectron spectroscopy techniques to analyze chemical composition, surface morphology, crystal structure, optical and electrical properties of samples prepared under different conditions.The results of the study show that the phase diffraction peak of CuS2 completely disappeared and formed a single phase of CIS when the annealing temperature is 550℃. At this time, the peak intensity ratio of (112) peak and total peaks is 87.8% and the degree of crystallization is best. The film structure is affected when the rare earth element Ce is doped in CuInS2-Absorption peaks of B(1710nm) and C(1955nm) occurred in the absorption coefficient of CuIn0.9Ce0.1S2 thin films correspond to the photon energies of 0.73eV and 0.63eV respectively. This indicates that the intermediate band (IB) has been partially filled. |
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