Change in Titania Structure from Amorphousness to Crystalline Increasing Photoinduced Electron-Transfer Rate in Dye-Titania System

Nishikiori, Hiromasa; Qian, Wei; El‐Sayed, Mostafa A.; Tanaka, Nobuaki; Fujii, Tsuneo

doi:10.1021/jp072625q

Cited by 48 publications

(75 citation statements)

References 19 publications

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“…Nishikiori et al [64] found that an increase in the overall crystallinity of TiO 2 nanoparticles increased the surface quality of the nanoparticles, which improved the anchoring geometry of the dye on their surfaces and led to faster electron injection. However, back electron transfer via recombination with oxidized dye molecules, which decreases the quantum yield of photon-to-current conversion, was also enhanced as the crystallinity of the TiO 2 nanoparticles was increased.…”

Section: Dye Sensitizationmentioning

confidence: 99%

A review of TiO2 nanoparticles

2011

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Climate change and the consumption of non-renewable resources are considered as the greatest problems facing humankind. Because of this, photocatalysis research has been rapidly expanding. TiO 2 nanoparticles have been extensively investigated for photocatalytic applications including the decomposition of organic compounds and production of H 2 as a fuel using solar energy. This article reviews the structure and electronic properties of TiO 2 , compares TiO 2 with other common semiconductors used for photocatalytic applications and clarifies the advantages of using TiO 2 nanoparticles. TiO 2 is considered close to an ideal semiconductor for photocatalysis but possesses certain limitations such as poor absorption of visible radiation and rapid recombination of photogenerated electron/hole pairs. In this review article, various methods used to enhance the photocatalytic characteristics of TiO 2 including dye sensitization, doping, coupling and capping are discussed. Environmental and energy applications of TiO 2 , including photocatalytic treatment of wastewater, pesticide degradation and water splitting to produce hydrogen have been summarized. Historical backgroundThe growth of industry worldwide has tremendously increased the generation and accumulation of waste byproducts. In general, the production of useful products has been focused on and the generation of waste byproducts has been largely ignored. This has caused severe environmental problems that have become a major concern. Researchers all over the world have been working on various approaches to address this issue. Photoinduced processes have been studied and various applications have been developed. One important technique for removing industrial waste is the use of light energy (electromagnetic radiation) and particles sensitive to this energy to mineralize waste which aids in its removal from solution. Titanium dioxide (TiO 2 ) is considered very close to an ideal semiconductor for photocatalysis because of its high stability, low cost and safety toward both humans and the environment.*Corresponding author (email: shipra.mital@gmail.com)In 1964, Kato et al.[1] published their work on the photocatalytic oxidation of tetralin (1,2,3,4-tetrahydronaphthalene) by a TiO 2 suspension, which was followed by McLintock et al. [2] investigating the photocatalytic oxidation of ethylene and propylene in the presence of oxygen adsorbed on TiO 2 . However, the most important discovery that extensively promoted the field of photocatalysis was the "Honda-Fujishima Effect" first described by Fujishima and Honda in 1972 [3]. This well-known chemical phenomenon involves electrolysis of water, which is related to photocatalysis. Photoirradiation of a TiO 2 (rutile) single crystal electrode immersed in an aqueous electrolyte solution induced the evolution of oxygen from the TiO 2 electrode and the evolution of hydrogen from a platinum counterelectrode when an anodic bias was applied to the TiO 2 working electrode. In 1977, Frank and Bard [4] examined the reduction of ...

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Section: Dye Sensitizationmentioning

confidence: 99%

A review of TiO2 nanoparticles

2011

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“…The carboxylate of fluorescein covalently bonding to the titania surface has been detected on by XPS analysis [29]. The absorbance decreased, the spectral peak of the film was red-shifted from around 480 to 485 nm, and the absorption band appeared at 500−600 nm by the steam treatment [14][15][16]30]. These results indicate that the anion was preferentially desorbed from the inside of the titania gel film because the species was weakly trapped in the pores of the gel.…”

Section: Effects Of Steam Treatmentmentioning

confidence: 99%

“…We strongly suggest that the fluorescein molecules formed a chelate complex with the titanium species on the titania surface to induce the interaction between their orbitals in the steam-treated electrodes based on the spectral red-shift. This interaction caused the ligand to metal charge transfer (LMCT) interaction and the fast electron injection to the titania conduction band [8,9,16,30].…”

Section: Dye-titania Interactionmentioning

confidence: 99%

Photo-electric conversion in dye-doped nanocrystalline titania films

Nishikiori

Uesugi

Tanaka

et al. 2009

Journal of Photochemistry and Photobiology A: Chemistry

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Influences of the titania nanostructure and dye dispersion in a dye-doped titania electrode on its photoelectric conversion property were investigated by simple spectroscopic and electric measurements.The dye-doped nanocrystalline titania electrodes were prepared on the glass plates coated with ITO and normal crystalline titania films by the following two procedures: (1) the dye-doped titania gel films were prepared from a titanium alkoxide solution containing the dye and then steam-treated, and (2) the titanium alkoxide sol containing the dye was refluxed and then spread onto the plates. The photocurrent quantum efficiency remarkably increased by the steam treatment and the reflux compared to that of the untreated dye-doped electrode consisting of amorphous titania gel. The efficiency in the former was higher than that in the latter. The growth and crystallization of the titania particles and the decrease in the defect density by these treatments improved the electric conductivity. The steam treatment was the more prominent method because it enhanced the electric conductivity of the titania depending on its nanostructure and the dye-titania interaction depending on the dye dispersion. These factors appear to play important roles in transport in the electron through the electrode.

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“…The xanthene dye-dispersing titania gel was prepared without heating from a titanium alkoxide sol containing the dye molecules by the sol-gel method [27][28][29][30][31]. Xanthene dyes as laser dyes are available materials for utilizing photoenergy due to their high absorption and fluorescence efficiencies in various visible light regions [32].…”

Section: Introductionmentioning

confidence: 99%

“…Xanthene dyes as laser dyes are available materials for utilizing photoenergy due to their high absorption and fluorescence efficiencies in various visible light regions [32]. It was reported that the hydrothermal treatment of a dye-dispersing amorphous titania film remarkably improved the photoelectric conversion efficiency due to not only its crystallization but also the dye-titanium complex formation [20][21][22][23][24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Interaction between dye and zinc in the dye-dispersing ZnO films prepared by a wet process

et al. 2014

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Dye-dispersing ZnO precursor gel films were prepared on indium tin oxide electrodes from a zinc acetate solution containing eosin Y by dip-coating, steam treatment, and then heating at a low temperature. The electronic interaction between the dye and zinc in the dye-dispersing gel films were investigated by spectroscopic and electrochemical measurements. A photocurrent was observed in the dye-dispersing gel electrodes before the steam treatment. The photocurrent value increased by the steam treatment and heating due to crystallization of the gel and removal of organic impurities. The dye molecules existed between the interlayers of the layered zinc hydroxide coexisting with the ZnO. The photoexcited electron in the dye should be injected into the ZnO conduction band via the layered zinc hydroxide. The value increased with an increase in the dye content even though the ZnO crystallinity decreased.The dye-zinc interaction, i.e., the complex formation and photoinduced electron injection, played an important role in the electron transport and photoelectric conversion.

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Change in Titania Structure from Amorphousness to Crystalline Increasing Photoinduced Electron-Transfer Rate in Dye-Titania System

Cited by 48 publications

References 19 publications

A review of TiO2 nanoparticles

A review of TiO2 nanoparticles

Photo-electric conversion in dye-doped nanocrystalline titania films

Interaction between dye and zinc in the dye-dispersing ZnO films prepared by a wet process

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