Direct observation of interfacial charge recombination to the excited-triplet state in all-trans-retinoic acid sensitized TiO2 nanoparticles by femtosecond time-resolved difference absorption spectroscopy
文献类型：期刊论文
| 作者 | Zhang, L ; Yang, J ; Wang, L ; Yang, GZ ; Weng, YX |
| 刊名 | JOURNAL OF PHYSICAL CHEMISTRY B
 |
| 出版日期 | 2003 |
| 卷号 | 107期号:49页码:13688 |
| 关键词 | PHOTOSYNTHETIC REACTION-CENTER ELECTRON-TRANSFER REACTIONS RAMAN EXCITATION PROFILES TITANIUM-DIOXIDE FILMS SOLAR-CELL REACTION RADICAL-ION-PAIRS RADIATIONLESS PROCESSES DYNAMICS INJECTION LIGHT |
| ISSN号 | 1520-6106 |
| 通讯作者 | Weng, YX: Chinese Acad Sci, Inst Phys, POB 603, Beijing 100080, Peoples R China. |
| 中文摘要 | The excited-state dynamics of all-trans-retinoic acid (ATRA), both free in n-hexanol and bound to a TiO2 nanoparticle have been studied by use of femtosecond time-resolved visible absorption spectroscopy excited at 400 nm. Three excited singlet states, S-3, S-2, and S-1, have been observed for the ATRA molecule, which can be assigned as 1B(u)(+) (pi, pi*), (n, pi*), and 2A(g)(-) (pi, pi*) singlet excited manifolds, respectively. Photoinduced electron injection from the excited singlet state S-3 to the conduction band of the TiO2 nanoparticle is observed in an ATRA-sensitized TiO2 colloidal solution in hexanol; the subsequent interfacial charge recombination between the injected electron and the ATRA cation is investigated. It is found that the charge recombination is mainly via the triplet state, and the branching ratio for the population on the excited triplet state and the ground state during the charge recombination is about 6.0. The observed rate constants for the charge recombination to the triplet state and the ground state are 1/19.0 (ps(-1)) and 1/140 (ps(-1)), respectively. Treating the charge recombination as a nonadiabatic process, we can obtain a reorganization energy having a value of 0.44 eV, which indicates that the charge recombination to the ground state is in the Marcus inverted region while the charge recombination to the triplet state lies within the normal region. An apparent electronic coupling matrix element at the closest contact of ATRA and the TiO2 nanoparticle, V-0(T) = 5118 cm(-1), has been evaluated for the charge recombination to the triplet state and V-0(G) = 2670 cm(-1) for that to the ground state. It is concluded that the interfacial charge recombination is strongly coupled. The electronic coupling matrix element is expected to decay exponentially on the charge separation distance, and in the microsecond domain, the observed V(r)(G) decays to 3.6 cm(-1), corresponding to the trapped electron migrating away from the adsorbates at a distance of 2.0 nm on the TiO2 nanoparticles. The relevance of the triplet formation to the electroluminescence device is also discussed. |
| 收录类别 | SCI |
| 语种 | 英语 |
| 公开日期 | 2013-09-17 |
| 源URL | [http://ir.iphy.ac.cn/handle/311004/36054]  |
| 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 | Zhang, L,Yang, J,Wang, L,et al. Direct observation of interfacial charge recombination to the excited-triplet state in all-trans-retinoic acid sensitized TiO2 nanoparticles by femtosecond time-resolved difference absorption spectroscopy[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2003,107(49):13688. |
| APA | Zhang, L,Yang, J,Wang, L,Yang, GZ,&Weng, YX.(2003).Direct observation of interfacial charge recombination to the excited-triplet state in all-trans-retinoic acid sensitized TiO2 nanoparticles by femtosecond time-resolved difference absorption spectroscopy.JOURNAL OF PHYSICAL CHEMISTRY B,107(49),13688. |
| MLA | Zhang, L,et al."Direct observation of interfacial charge recombination to the excited-triplet state in all-trans-retinoic acid sensitized TiO2 nanoparticles by femtosecond time-resolved difference absorption spectroscopy".JOURNAL OF PHYSICAL CHEMISTRY B 107.49(2003):13688. |
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来源：物理研究所
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