Improvement of charge transportation in Si quantum dot-sensitized solar cells using vanadium doped TiO2

Hyunwoong Seo, Daiki Ichida, Shinji Hashimoto, Naho Itagaki, Kazunori Koga, Masaharu Shiratani, Sang Hun Nam, Jin Hyo Boo

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The multiple exciton generation characteristics of quantum dots have been expected to enhance the performance of photochemical solar cells. In previous work, we first introduced Si quantum dot for sensitized solar cells. The Si quantum dots were fabricated by multi-hollow discharge plasma chemical vapor deposition, and were characterized optically and morphologically. The Si quantum dot-sensitized solar cells had poor performance due to significant electron loss by charge recombination. Although the large Si particle size resulted in the exposure of a large TiO2 surface area, there was a limit to ho much the particle size could be decreased due to the reduced absorbance of small particles. Therefore, this work focused on decreasing the internal impedance to improve charge transfer. TiO2 was electronically modified by doping with vanadium, which can improve electron transfer in the TiO2 network, and which is stable in the redox electrolyte. Photogenerated electrons can more easily arrive at the conductive electrode due to the decreased internal impedance. The dark photovoltaic properties confirmed the reduction of charge recombination, and the photon-to-current conversion efficiency reflected the improved electron transfer. Impedance analysis confirmed a decrease in internal impedance and an increased electron lifetime. Consequently, these improvements by vanadium doping enhanced the overall performance of Si quantum dot-sensitized solar cells.

Original languageEnglish
Pages (from-to)4875-4879
Number of pages5
JournalJournal of nanoscience and nanotechnology
Volume16
Issue number5
DOIs
Publication statusPublished - May 2016

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics

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