Numerical simulation and performance optimization of GeSe based thin film solar cell with NiO as back surface field layer

Germanium monoselenide (GeSe) has emerged as a viable candidate for absorber material in thin film solar cell (TFSC) due to its favorable material characteristics. Herein, the novel GeSe based TFSC with CdS as buffer layer and NiO as back surface field (BSF) layer has been proposed and its photovoltaic performance has been evaluated theoretically using wxAMPS software. The device output parameters have been assessed by varying thickness and carrier concentration for the GeSe layer, CdS layer and NiO layer, respectively. Moreover, the defect densities in GeSe absorber layer, CdS/GeSe and GeSe/NiO interface layers, and the work function of metal electrode at the cell rear side have been altered to evaluate the photovoltaic characteristics. Conversion efficiency of 31.37% has been obtained for the proposed GeSe-based TFSC with the new architecture under the conditions such as the thicknesses of the CdS layer, GeSe layer and NiO layer are optimized to be 0.03 μm, 0.3 μm and 0.05 μm, respectively; the carrier concentrations of the CdS layer, GeSe layer and NiO layer are optimized to be 1018 cm−3, 1019 cm−3 and 1020 cm−3, respectively; the defect densities in the GeSe layer, IDL1, IDL2 both are set to be 1015 cm−3. These results suggest that GeSe can be employed as the promising absorber layer to fabricate low-cost and high efficiency TFSC.