Liquid carbon dioxide coating of CdS quantum-dots on mesoporous TiO 2 film for sensitized solar cell applications

Wonho Jang, Eduardus Budi Nursanto, Jaehoon Kim, Se Jin Park, Byoung Koun Min, Ki Pung Yoo

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CdS quantum dots (QDs) were uniformly deposited on mesoporous TiO 2 films by high-pressure coating with liquid carbon dioxide (l-CO 2) as a coating solvent. The size and coverage of CdS QDs over the TiO 2 surface were controlled by the number of l-CO 2 coating cycles applied at a fixed precursor concentration. The formation of CdS QDs on the mesoporous TiO 2 film was confirmed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, depth profiling investigation revealed that CdS QDs were uniformly deposited throughout the ∼15 μm-thick mesoporous TiO 2 film. The energy conversion efficiency of a CdS QD-sensitized solar cell (QDSSC) was observed to increase up to ∼1.33% under standard conditions (1.5 AM, 100 mW cm -2) with an increase in the number of coating cycles to six. Meanwhile, a further increase in the number of coating cycles to ten caused a decrease in the cell performance, which may be attributed to the hindrance of electrolyte infiltration into the mesoporous TiO 2 electrode caused by the blocking of the pores with the coated CdS. The cell performance of the l-CO 2-coated CdS-QDSSC is slightly higher than that of the l-CO 2-coated CdS-QDSSC prepared by a conventional successive ionic layer absorption and reaction (SILAR) method with ethanol as the solvent (1.16%).

Original languageEnglish
Pages (from-to)40-47
Number of pages8
JournalJournal of Supercritical Fluids
Publication statusPublished - 2012 Oct 1



  • CdS
  • Coating
  • Liquid carbon dioxide
  • Quantum dot
  • Sensitized solar cells

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Chemical Engineering(all)
  • Condensed Matter Physics

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