Tuning the bandgap of Cd1-xZnxS (x = 0~1) buffer layer and CIGS absorber layer for obtaining high efficiency.

This numerical study deals with the CIGS solar cell considering Cd 1-x Zn x S buffer layer. The composition 'x' of the buffer layer is determined and its impact on the solar cell performance parameters is studied. The influence of the buffer layer thickness on quantum efficiency is also discussed. The tuned bandgap and optimized thickness of the Cd 1-x Zn x S buffer layer are then utilized to obtain the suitable bandgap of the CIGS absorber layer. The maximum power conversion zone is revealed in terms of the CIGS bandgap and the impact of this bandgap on spectral response as well as performance parameters are discussed. The Cd 0.6 Zn 0.4 S/CIGS interface is studied by varying the defect density from 1010 cm−3 to 1016 cm−3. The cell performances are also analyzed for the temperature ranging from 260 K to 350 K. • The optimized concentration of Zn in Cd 1-x Zn x S buffer is 0.4 corresponding to the bandgap of 2.83 eV. • For a 50 nm thin Cd 0.6 Zn 0.4 S buffer layer, highest QE is achieved. • The proposed cell structure exhibits an efficiency of 26.02% for CIGS bandgap of 1.4 eV. • The cell performance degrades with the increase of InCd 0.6 Zn 0.4 S/CIGS interface defect density and temperature. [ABSTRACT FROM AUTHOR]