Research On Preparation Of AZO Nanowire Window Layer And Bending Mechanism In Flexible CZTS Solar Cell

Flexible CZTS solar cells are flexible,light in weight and not easily damaged,which enable them to be used in areas different from traditional crystalline silicon cells.At present,the main challenge for the development of flexible CZTS solar cells is how to improve the conversion efficiency and the stability of multiple use.In order to improve the conversion efficiency and promote the further development of flexible CZTS solar cells,this paper focuses on the alkali metal doping of CZTS cells,the preparation process of novel potential window layer structure AZO nanowires,and the bending mechanism of cells.The main contents of this paper are as follows:(1)Three kinds of alkali metals(Li,Na,K)are doped in the CZTS thin films.The effects of alkali metal doping amount and different alkali metals of the same family on the performance of CZTS thin films and cells are systematically studied.The different amount of alkali metal doping has different effects on the morphology of CZTS thin films and the performance of the cell.Among the three alkali metals with the same doping amount of Li,Na,and K,the CZTS solar cell doped with Na has the best performance with a conversion efficiency of 1.97%.(2)AZO nanowires are prepared on the substrate containing ZnO seed layer by hydrothermal method.The effects of growth temperature,reactant concentration ratio,Al doping amount and reactant concentration on the morphology,structure and optical properties of AZO nanowires are studied.Two kinds of samples with nanowire array structure and nanowire film structure are prepared in the study of reactant concentration.Then,the physical models of two kinds of nanowire structure window layer and traditional film structure window layer are established by using simulation software.The optical properties of three kinds of window layer are compared,and it is found that the window layer of nanowire array structure has the best optical properties.Subsequently,a simulation study on the array structure window layer with different nanowire structure parameters shows that the nanowire array structure with a nanowire length of 1.2μm,a smaller diameter and a larger interval has the best optical performance.(3)A series of bending tests on flexible CZTS solar cells are carried out by using the bending device invented by our research group.The effects of bending radius and bending times on flexible CZTS solar cells are studied.It is found that the smaller the bending radius and the more bending times,the more unfavorable the performance of flexible CZTS solar cells.The physical models of new flexible CZTS solar cells with nanowire array window layer structure and traditional flexible thin film CZTS solar cells are established by using simulation software.The simulation results shows that nanowire array window layer has the advantage of replacing traditional thin film window layer.The deformation and stress of new flexible CZTS solar cell with different nanowire structure parameters are investigated.It is found that the flexible CZTS solar cell with a nanowire length of1.2μm,a diameter of 250nm,and an interval of 200nm has the best performance after bending.