Synergistic Interplay between CsPbBr3 Nanocrystals and N719 Dye through Interfacial Engineering to Achieve High Efficiency in Dye-Sensitized Solar Cells

Abstract Among nanocrystals (NCs)/quantum dots (QDs), halide perovskite NCs/QDs have emerged as promising nanomaterials owing to their tunable band gaps, efficient charge transport, defect tolerance, high absorption coefficients, and low manufacturing costs. In this work, we successfully synthesized CsPbBr3 nanocrystals (PNCs) and applied them as an interfacial layer between the dye and the electrolyte to improve the performance of dye-sensitized solar cells (DSSCs). It was revealed that PNCs not only act as co-sensitizers, thereby improving light harvesting but also as hole-transporting materials, thereby enhancing charge separation and transport within the device. These PNCs exhibit defects during synthesis that act as traps for charge transport. It was found that the N719 dye bonded to the PNCs, thereby suppressing defects and recombination losses. The synergistic effect of PNC-hole transport and N719-dye-induced defect passivation significantly enhances device performance. Photovoltaic parameters, including short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and overall power conversion efficiency, were systematically evaluated. A high PCE of 14.21% was achieved in a DSSC using a combination of PNCs and the N719 dye. Overall, this work highlights an effective strategy to improve DSSC efficiency through defect engineering and interfacial optimization and offers valuable insights for the future development of high-performance DSSCs.