Introduction of Co atoms into CdS thin films for improving photovoltaic properties

Yılmaz S., Doğan V., TOMAKİN M., Töreli S., POLAT İ., BACAKSIZ E.

Materials Today Communications, vol.39, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 39
  • Publication Date: 2024
  • Doi Number: 10.1016/j.mtcomm.2024.108805
  • Journal Name: Materials Today Communications
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
  • Keywords: Co-doped CdS thin films, Hybrid solar cell, Optical properties, P3HT:PCBM, Physical investigation
  • Karadeniz Technical University Affiliated: Yes


This paper represents a systematic work on the fabrication of chemical bath-grown CdS films with and without Co atoms and their photovoltaic performances in hybrid solar cells. Structural properties showed 1% Co-doping promoted crystal quality of CdS films. However, a poor crystal quality was developed above 3% Co concentrations. A reduction in sphere size of CdS samples was observed for 1% Co-doping which was ascribed to slow growth of film. Optical examination demonstrated CdS films with 1% Co-doping displayed the highest transparency of 85% in the visible and near-infrared regions, which were explained by the improvement of crystal quality. A maximum band gap of 2.43 eV was found for 1% Co-doped CdS films, whereas an increase in Co concentration to 7% led to a decline in the band gap of CdS that was attributed to sp-d exchange interaction. Photoluminescence data showed Co-doped CdS films had lower PL peak intensity than that of CdS, demonstrating a decrease in the number of intrinsic defects. Photovoltaic measurements displayed that the best efficiency of 0.488% was achieved for CdS-based device including 1% Co atoms, which were almost a seven-fold boost in overall efficiency compared to bare CdS-based device. The enhancement in power conversion efficiency originated from an increase in short-circuit current density of 1% Co-doped CdS-based photovoltaic cell.