title: Simple preparation of lotus-root shaped meso-/macroporous TiO₂ and their DSSC performances.
abstract: In pursuit of superior TiO2 photoanode materials for dye-sensitized solar cells (DSSCs), we prepared lotus-root shaped meso-/macroporous TiO2. The lotus-root shaped meso-/macroporous TiO2 was easily prepared by using a cetyltrimethylammonium hydroxide (CTAOH) template in aqueous solution. The crystallization of the as-prepared amorphous lotus-root shaped TiO2 was performed at 700 °C in air. Crystalline anatase phase with a very small portion of rutile phase was generated after the heat treatment at 700 °C and the BET surface area of crystalline lotus-root shaped meso-/macroporous TiO2 material (LR-700) was 30.0 m(2) g(-1). The wall of LR-700 displayed well-developed mesoporosity with a pore dimension of 28.3 nm. Periodically arranged microscale one-dimensional (1D) macropores were also observed in the particles. The photon-to-current conversion efficiencies (η) of LR-700 photoanodes in Grätzel type DSSCs were examined. The conversion efficiency of DSSC prepared by mixing nanoparticulate Evonik P25 and LR-700 (ratio=85:150 by mass) was 28% greater compared to the reference electrode using P25. Incident photon-to-current efficiencies (IPCE) of the DSSCs were dramatically improved by employing the photoanodes composed of a mixture of P25 and LR-700 but impedance analysis indicated that P25/LR-700 mixed cells have resistances similar to the standard P25 reference cell. Thus, photovoltaic performances could be improved mainly due to the increases of dye uptake and external quantum efficiency by using a mixed photoanode composed of LR-700 and nanocrystalline P25 particles.
authors.affiliation: Department of Chemistry and Protein Research Center for Bio-Industry, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
authors.forename: Jin-Yeon
authors.initials: JY
authors.lastname: Hong
authors.affiliation: Department of Chemistry and Protein Research Center for Bio-Industry, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Bae
authors.affiliation: Department of Chemical Engineering, Pukyong National University, Pusan 608-739, Republic of Korea. Electronic address: yswon@pknu.ac.kr.
authors.forename: Yong Sun
authors.initials: YS
authors.lastname: Won
authors.affiliation: Department of Chemistry and Protein Research Center for Bio-Industry, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea. Electronic address: shuh@hufs.ac.kr.
authors.forename: Seong
authors.initials: S
authors.lastname: Huh
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D003460:Crystallization; D011211:Electric Power Supplies; D004566:Electrodes; D016062:Porosity; D012993:Solar Energy; D014025:Titanium / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; C009495:titanium dioxide; D014025:Titanium
keywords: Dye-sensitized solar cell; Photoanode; Photovoltaics; Porous materials; TiO(2)