Research On Fabrication Of Sb₂Se₃ Thin Films By VTD Method And Application For Superstrate-type Solar Cells

Antimony selenide?Sb₂Se₃?may become an ideal absorption layer material instead of cadmium telluride?CdTe?thin film solar cells in the future because of its high optical absorption coefficient,suitable band gap??1.2 eV?,low cost,earth abundant,environmental protection and nontoxicity.At present,there are many ways to prepare Sb₂Se₃ solar cells.The highest efficiency of Sb₂Se₃ solar cells with CSS?closed space sublimation?method is 9.2%,which is still far away from the pilot test efficiency of 15%.Therefore,it is necessary to go deep into the research of Sb₂Se₃ solar cells.In this paper,Sb₂Se₃ thin films were prepared by VTD?vapor transport deposition?method.Sb₂Se₃ thin films with larger grains were obtained and solar cell devices were prepared.The photovoltaic performance of the devices was also studied.This paper consists of three parts:1.Preparation of Sb₂Se₃ thin films:Sb₂Se₃ thin films were prepared on different substrates by VTD method.The mechanism of Sb₂Se₃ thin films grown by VTD was studied.Because Sb₂Se₃ has strong anisotropy,the preferred orientation of Sb₂Se₃ is[371]on glass/Au substrate,[430]on glass/Al substrate,and[221]on FTO,FTO/ZnO,FTO/SnO₂,FTO/TiO₂,FTO/CdS substrate.2.Sb₂Se₃ thin film solar cell with superstructure FTO/CdS/Sb₂Se₃/Au was prepared,and its preparation process was optimized.The effects of substrate inclination angle and evaporation source-substrate distance on the efficiency of Sb₂Se₃ thin film solar cell were studied,and the highest efficiency of the device was 3.8%.3.by adding the oxide resistance layer on FTO,the interface of Sb₂Se₃ thin film solar cells can be effectively improved.It is found that the SnO₂ prepared by spray pyrolysis is more effective than the TiO₂ high resistivity layer,and the efficiency of the device is increased to 4.43%after optimization.In addition,reducing the thickness of CdS can reduce its absorption loss and further improve the efficiency of the device.Finally,when the time of chemical bath deposition is13 min 30 s,the average maximum efficiency of the device is 5.25%.Among them,the champion device efficiency is 6.14%,the specific parameters are V_oc=0.391 V,J_sc=28.66 mA/cm²,FF=54.91%.In this paper,the leakage channel and weak diode region in Sb₂Se₃ thin film solar cell and their formation mechanism are proposed.Tin dioxide dense layer with high resistance is added to the device to reduce the leakage channel,and the interface recombination is effectively reduced by reducing the thickness of the buffer layer CdS,so as to improve the efficiency of the solar cell.This paper will provide a promising route for the further improvement of the efficiency of Sb₂Se₃ solar cell.In addition,VTD is simple,non-toxic,and can be applied in industry.It provides a feasible way for the preparation of low-cost and high-efficiency solar cells.