Boosting PbS CQD Solar Cell Efficiency: Harnessing Graded Band Alignment with MXene+TiO 2 Electron Transport Layers

The effectiveness of colloidal quantum dots (CQDs) is impacted by the considerable recombination in the device quasi-neutral region (QNR). By incorporating a graded band alignment technique for the QDs, it is possible to resolve the recombination issue at the QNR of the device. When employed for solar cells, there performance is significantly impacted by the effect of the electron transport layers. In this study, with the electron transport layer (ETL) formed of MXene and TiO ₂ and a PbS CQD crystal layer coated with an absorber of tetrabutylammonium iodide (PbS-TBAI) based colloidal quantum dot solar cell (CQDSC), a modeling study has been carried out resulting in the optimized power conversion efficiency (PCE) around 16.35%. The best bandgap alignment in the MXene + TiO ₂ material's ETL is used for CQDSC optimization. To better comprehend the collection of the carriers, the quantum efficiency (QE) is also investigated for different ETLs. The simulated device's impedance analysis also provides a lower value for a better carrier flow in the Mxene + TiO ₂ -based ETL for improved device performance.