The Study Of Antimony Sulfide Thin-Film Solar Cell Via Vapor Transport Deposition

The development of the solar energy industry is regarded as a significant strategy to handle the crisis of energy.Considerable attention has been directed toward the thin film solar cells because of their advantages of high photoelectric conversion efficiency,low cost and high productivity in the field of photovoltaic devices.As an emerging promising photoabsorber thin-film material,antimony sulfide not only(Sb₂S₃)has abundant reserves and low toxicity,but also has drawn wide attention due to its excellent optical and electrical properties,such as ideal band gap(1.7e V-1.8e V),high absorption coefficient above 10⁵ cm^-1 at short wavelength,and decent carrier mobility.So far,the highest efficiency of Sb₂S₃ solar cell has reached 7.5%.Researchers have enhanced the efficiency by improving the structure of cells or technological innovation of the absorber layer preparation,which is still far from its theoretical photoelectric conversion efficiency.To study Sb₂S₃ solar cells further,in this thesis,we produced the Sb₂S₃ thin films via vapor transport deposition(VTD),which is a practical method that easy to control the deposition rate.We explored the morphology characterization of Sb₂S₃ thin films and J-V characteristics of Sb₂S₃ solar cells under different process conditions.By means of admittance spectroscopy,we studied the effect of process conditions on defect passivation.Moreover,based on SCAPS software,the effects of different types of defects on the Sb₂S₃ solar cell performance were assessed.The results of numerical analyses are expected to provide crucial guidance for further experimental efforts to passivate defects toward better device performance.The main research contents of this thesis are as follows:(1)We prepared Sb₂S₃ thin films under different source temperatures,the distances between the source and the substrate,deposition pressure,deposition times and heating rates via the VTD method.Morphology and components of thin films were characterized to explore the optimal preparation conditions.(2)We fabricated Sb₂S₃ thin-film solar cells based on the Sb₂S₃ thin films prepared by the VTD method.The solar cell had a structure of ITO/Cd S/Sb₂S₃/Au and their device performances were characterized through the light J-V measurement.By using admittance spectroscopy,we further measured the defect characterizations in Sb₂S₃solar cell samples with different efficiencies under different source temperatures,and the effects of different process conditions on defect parameters(defect density,activation energy,capture cross-section and capture life)has been discussed.(3)By using SCAPS software,we established a Sb₂S₃ solar cell model with the same structure as the experiments.For numerical simulation,we first introduced a single defect into various locations(the Sb₂S₃ absorber layer and the Cd S/Sb₂S₃interface)of the Sb₂S₃ solar cell model and assess its effect on cell performance.Then we try to distinguish the types of the actual defects obtained from experimental measurements,followed by investigating the contribution of each defect to cell performance degradation.