Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle

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	Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle
	Pan, J ; Benko, G ; Xu, YH ; Pascher, T ; Sun, LC ; Sundstrom, V ; Polivka, T
刊名	JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
	2002
卷号	124 期号:46 页码:13949
关键词	BETA-CAROTENE SPHEROIDENE ANALOGS DIFFERENT EXTENTS TITANIUM-DIOXIDE ENERGY-TRANSFER PHOTOSYSTEM-II EXCITED-STATES THIN-FILMS S-1 STATE SEMICONDUCTOR
ISSN号	0002-7863
通讯作者	Polivka, T (reprint author), Lund Univ, Dept Chem Phys, Box 124, S-22100 Lund, Sweden.
中文摘要	The dynamics of photoinduced electron injection and recombination between all-trans-8'-apo-beta-caroten-8'-oic acid (ACOA) and a TiO2 Colloidal nanoparticle have been studied by means of transient absorption spectroscopy. We observed an ultrafast (similar to360 fs) electron injection from the initially excited S-2 state of ACOA into the TiO2 conduction band with a quantum yield of similar to40%. As a result, the ACOA(.+) radical cation was formed, as demonstrated by its intense absorption band centered at 840 nm. Because of the competing S-2-S-1 internal conversion, similar to60% of the S-2-state population relaxes to the S-1 state. Although the S-1 state is thermodynamically favorable to donate electrons to the TiO2, no evidence was found for electron injection from the ACOA S, state, most likely as a result of a complicated electronic nature of the S, state, which decays with a similar to18 ps time constant to the ground state. The charge recombination between the injected electrons and the ACOA(.+) was found to be a highly nonexponential process extending from picoseconds to microseconds. Besides the usual pathway of charge recombination forming the ACOA ground state, about half of the ACOA(.+) recombines via the ACOA triplet state, which was monitored by its absorption band at 530 nm. This second channel of recombination proceeds on the nanosecond time scale, and the formed triplet state decays to the ground state with a lifetime of similar to7.3 mus. By examination of the process of photoinduced electron transfer in a carotenoid-semiconductor system, the results provide an insight into the photophysical properties of carotenoids, as well as evidence that the interfacial electron injection occurs from the initially populated excited state prior to electronic and nuclear relaxation of the carotenoid molecule.
收录类别	SCI
语种	英语
公开日期	2013-09-24
内容类型	期刊论文
源URL	[http://ir.iphy.ac.cn/handle/311004/50925]
专题	物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文
推荐引用方式 GB/T 7714	Pan, J,Benko, G,Xu, YH,et al. Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,2002,124(46):13949.
APA	Pan, J.,Benko, G.,Xu, YH.,Pascher, T.,Sun, LC.,...&Polivka, T.(2002).Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle.JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,124(46),13949.
MLA	Pan, J,et al."Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle".JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 124.46(2002):13949.