Performance improvement tactics of sensitized solar cells based on CuInS2 quantum dots prepared by high temperature hot injection

• Published in: Solid state ionics Vol. 418; p. 116731
• Main Authors: Li, Yushan, Men, Jiao, Zhou, Guangyan, Qiao, Yanhong, Zhang, Jingbo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2024
• Subjects: Compact layer; CuInS2 quantum dots; Quantum dot-sensitized solar cells; Sensitizing processes; Quantum dot-sensitized solar cells; Sensitizing processes; Compact layer; CuInS2 quantum dots
• ISSN: 0167-2738
• DOI: 10.1016/j.ssi.2024.116731

To reveal the ways and causes of conversion efficiency enhancement for quantum dot-sensitized solar cells (QDSSCs), chalcopyrite structure CuInS2 quantum dots (QDs) was synthesized in oil phase by the high temperature hot injection method. Then, QDs were transferred from oil phase to water phase with 3-mercaptopropionic acid as a ligand exchange reagent and loaded inducer of QDs. 3-mercaptopropionic acid coated QDs in water phase were sensitized on TiO2 nanocrystalline thin films to fabricate QDSSCs. The sensitization time of QDs and pH value in QDs solution are two important factors to affect the loading amounts of QDs and performance of the final assembled QDSSCs. Long-time sensitization of QDs on the TiO2 porous thin film will cause QDs to agglomerate and stack on the film. The pH of QDs aqueous solution influences the stable existence in solution of QDs and adsorption on the surface of TiO2. By balancing the influence of the above two factors, the optimal sensitization condition of CuInS2 QDs is adsorption in pH = 11 QDs solution for 2 h. In addition, the interface between QD-sensitized TiO2 porous thin film and FTO is another factor to affect the photoelectric conversion efficiency of QDSSCs. By adding Zn-doped TiO2 compact layer with high conductivity and electron mobility on QDSSCs to modify this interface, the photoelectric conversion efficiency of QDSSCs was further increased by 66.4 %. •The surface aggregation of quantum dots on TiO2 thin film is controlled by the deposition time.•The surface contact of quantum dots on TiO2 is adjusted by pH of quantum dot solution.•Zn doped TiO2 compact layer prepared by vacuum ultraviolet is used to improve the cell efficiency.•It shows deep understanding to further improve efficiency of quantum dot-sensitized solar cell.