Dye-sensitized semiconductor

Photoelectrochemical conversion from visible light to electric and/or chemical energy using dye-sensitized semiconductor or metal electrodes is a promising system for the in vitro simulation of the plant photosynthetic conversion process, which is considered one of the fundamental subjects of modern and future photoelectrochemistry. Use of chlorophylls(Chls) and related compounds such as porphyrins in photoelectric and photoelectrochemical devices also has been of growing interest because of its close relevance to the photoacts of reaction center Chls in photosynthesis. 

Chl-coated semiconductor (n-type) electrodes and metal electrodes can act as efficient photoanodes and photocathoes, respectively, for visible light conversion. The former system functions as a dye-sensitized semiconductor electrode, while the latter is presumably driven by the photoconductive properties of a Chi solid layer and/or charge separation involving the Chl-metal contact barrier. 

A significant drawback of metals for photoelectrochemical applications lies in their ability to efficiently quench excited states via energy transfer processes, as discussed below. Direct detection of photosensitized electron transfer to or from a metal electrode surface has been observed [30]. However, unlike dye-sensitized semiconductor systems, little examination of the kinetics of such systems has yet been undertaken. 

Dye-sensitized semiconductors continue to be the focus of considerable research as a consequence of their importance in photovoltaic technologies, with the theories and mechanisms behind their operation also emerging. Considerably less is known about photoinduced interfacial processes in large photochemically active adsorbates on metals. ISAs on metals are becoming increasingly prevalent and are possible precursors for suitable molecular electronic devices. It would seem likely that over the coming years fundamental studies on the photophysics and chemistry of these materials will become more widespread. 

Simultaneous electrodeposition of ZnO and dye molecules from aqueous solution was reported as well to achieve a deeper penetration of the dye molecules into the inorganic film, as compared with those obtained by adsorption of dye molecules by the pre-assembled particles (mostly limited to the top layers). Yoshida and coworkers (2000) conducted such deposition process in an aqueous solution of Zn (N03)2 and eosin Y at 70°C and obtained ZnO/eosin Y dye-sensitized semiconductor films without high temperature annealing. The eosin Y molecules condensed at a sufficiently high concentration at both inside and on the surface of the film, which improved light absorption and IPCE. 

G. Primary Electron Transfer Dynamics of Dye-Sensitized Semiconductor Solar Cell Devices... 

Dye-sensitized semiconductor Adsorbing a suitable dye on the surface of a wide band gap semiconductor (like Ti02) can... 

Solar-based strategies for the conversion of the sun s light to electrical and chemical energy required the discovery of a new generation of specifically designed and engineered photonic materials. Examples of these inorganic semiconductors include those based on amorphous silicon, cadmium telluride, and more complex ternary or quaternary combinations such as copper iridium diselenide or dye-sensitized semiconductors. 

Study of dye-sensitized semiconductor electrodes has started in the late 1960s as an extension of photographic science where silver hahde grains are photosensitive materials to be spectrally sensitized. Dye molecules adsorbed on the surface of silver halide crystals and photoexcited by absorption of visible light act as electron... 

G. Ramakrishna, A. D. Jose, D. Krishnakumar, A. Das, D. K. Palit, and H. N. Ghosh, 2005. Strongly coupled ruthenium-polypyridyl complexes for efficient electron injection in dye-sensitized semiconductor nanoparticles. J. Phys. Chem. B 109,15445-15453. 

Persson P, Lundqvist MJ, Emstorfer R, Goddard WA ID, Willig F (2(X)6) Quantum chemical calculations of the influence of anchor-cum-spacer groups on femtosecond electron transfer times in dye-sensitized semiconductor nanocrystals. J Chem Theor Comp 2(2) 441-451... 

Shimidzu, T. lyoda, T. Koide, Y. An advanced visible-light-induced water reduction with dye-sensitized semiconductor powder catalyst. J. Am. Chem. Soc. 1985,107, 35 1. 

Takeshita, K. Sasaki, Y Kobashi, M. Tanaka, Y Maeda, S. Yamakata, A. Ishibashi, T Onishi, H. Photophysics and electron dynamics in dye-sensitized semiconductor film studied by time-resolved mid-IR spectroscopy. J. Phys. Chem. 2003, 107, 4156-4161. 

Electron-Cation Charge Recombination in Dye Sensitized Semiconductor Materials... 

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