Numerical Simulation and Optimisation of Wide Bandgap (1.45eV) PbS-CQD Solar Cell for 14% Conversion Efficiency

Lead sulfide (PbS) colloidal quantum dots (CQDs) are one of the emerging materials in the field of solar cell owing to large absorption coefficient and tunable bandgap. The performance of such devices suffers owing to the material quality of the PbS CQD based absorber layer. The conversion efficiency could be elevated by gauging the absorber layer thickness along with bulk defect density. In this context, the present manuscript provides a detailed investigation of wide bandgap (Eg=1.45eV) based PbS CQD absorber layer solar cell. Absorber layer thickness and bulk defect density variation is being done for optimizing the conversion efficiency. This has been accepted by varying the bulk defect density from 1x1014 cm-3 to 6x1016 cm-3 and the thickness from 50 nm to 500 nm in 10 steps each. In total, 100 simulations are performed to examine the ramifications of defect density at each thickness value and vice versa. SCAPS-1D simulation revealed the highest conversion efficiency of 14% at the thickness of 500 nm and bulk defect density of 1x1014 cm-3. The studies carried out in this work could help the researchers to develop high-efficiency wide-bandgap PbS CQD solar cells for standalone and tandem applications.