Preparation of TiO2 spheres with hierarchical pores via grafting polymerization and sol-gel process for dye-sensitized solar cells

Jung Tae Park, Dong Kyu Roh, Rajkumar Patel, Eunhye Kim, Du Yeol Ryu, Jong Hak Kim

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Abstract

Titania (TiO2) nanoparticles were surface-modified via atom transfer radical polymerization (ATRP) with hydrophilic poly(oxyethylene) methacrylate (POEM), which can coordinate to the TiO2 precursor, titanium(IV) isopropoxide (TTIP). Following application of a sol-gel process and calcination at 450 °C, TiO2 nanospheres with hierarchical pores were generated, as confirmed by the shifting of conduction bands in TiO 2 using UV-visible spectroscopy and X-ray photoelectron spectroscopy (XPS). The particle size and morphology of TiO2 were characterized using wide angle X-ray scattering (WAXS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Brunauer-Emmett-Teller (BET) analysis revealed bimodal distribution of TiO 2 pore sizes with peaks at 6 nm and 50 nm to afford better penetration of polymer electrolyte, as confirmed by electrochemical impedance spectroscopy (EIS). Dye-sensitized solar cells (DSSC) made from TiO2 nanospheres with hierarchical pores exhibited improved photovoltaic efficiency (3.3% for low molecular weight (Mw) and 2.5% for high Mw polymer electrolytes), as compared to those from neat TiO2 nanoparticles (2.4% for low Mw and 1.3% for high Mw) at 100 mW/cm2, owing to the increased surface areas and light scattering.

Original languageEnglish
Pages (from-to)8521-8530
Number of pages10
JournalJournal of Materials Chemistry
Volume20
Issue number39
DOIs
Publication statusPublished - 2010 Oct 21

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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