期刊
CHEMISTRY-A EUROPEAN JOURNAL
卷 17, 期 35, 页码 9626-9633出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.201100583
关键词
electronic structure; nanostructures; photochromism; polyoxometalates; self-assembly
资金
- Korea Ministry of Environment [191-101-001]
- National Research Foundation of Korea
- Korean Government [KRF-2008-313-C00442, 2010-0001485]
- Pioneer Research Center through the National Research Foundation of Korea
- Ministry of Education, Science and Technology [2010-0002190]
- MOST
- POSTECH
Nanohybrids of CdS-polyoxotungstate with strongly coupled electronic structures and visible-light-active photofunctions can be synthesized by electrostatically derived self-assembly of very small CdS quantum dots, or QDs, (particle size approximate to 2.5 nm) and polyoxotungstate nanoclusters (cluster size approximate to 1 nm). The formation of CdS-polyoxotungstate nanohybrids is confirmed by high-resolution transmission electron microscopy, elemental mapping, and powder X-ray diffraction analysis. Due to the strong electronic coupling between two semiconductors, the CdS-polyoxotungstate nanohybrids show a narrow bandgap energy of around 1.9-2.7 eV, thus reflecting their ability to harvest visible light. Time-resolved photoluminescence experiments indicate that the self-assembly between nanosized CdS and polyoxotungstate is very effective in increasing the lifetime of holes and electrons, thus indicating an efficient electron transfer between two-component semiconductors. The hybridization results not only in a significant improvement in the photostability of CdS QD but also in the creation of visible-light-induced photochromism. Of particular importance is that the present nanohybrids show visible-light-driven photocatalytic activity to produce H-2 and O-2, which is superior to those of the unhybridized CdS and polyoxotungstate. The self-assembly of nanometer-level semiconductor clusters can provide a powerful way of optimizing the photoinduced functionalities of each component (i.e., visible-induced photochromism and photocatalysis) by means of strong electronic coupling.
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