Enhancing the photoinduced charge carrier transfer by coupling the InZnP quantum-dots with PbS shell for solution-processed solar cells application

The III-V group colloidal quantum dots (CQDs) have been successfully synthesized with stable and low-cost chemical reagents recently, but they are rarely used for solid state solar cells due to the poor charge carrier transfer in solid films. In this work, the surface of InZnP (Zn doped InP) CQDs has been reconstructed with PbS via a chemical engineering strategy. Comparing with InZnP CQDs, the long carbon chain ligands capped on the InZnP@PbS CQDs surface can be easily exchanged with small molecules. By capping the mercaptopropionic acid (MPA) onto the InZnP@PbS CQDs surface, the electrical coupling between the InZnP@PbS CQDs has been established, and the photoinduced charge carrier transfer has been significantly enhanced. Based on the above CQDs, solid state solar cell devices are assembled, achieving about 1.5% of power conversion efficiency (PCE). The photoelectric performances of the fabricated solar cells almost do not decay after 150 days storage. Current work may provide a new way for III-V group CQDs application in solution-processed optoelectronics.