Self-assembly of nanosized 0D clusters: CdS quantum dot-polyoxotungstate nanohybrids with strongly coupled electronic structures and visible-light-active photofunctions

Hyo Na Kim, Tae Woo Kim, Kyong Hoon Choi, In Young Kim, Yong Rok Kim, Seong Ju Hwang

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

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 ≈ 2.5 nm) and polyoxotungstate nanoclusters (cluster size ≈ 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.

Original languageEnglish
Pages (from-to)9626-9633
Number of pages8
JournalChemistry - A European Journal
Volume17
Issue number35
DOIs
Publication statusPublished - 2011 Aug 22

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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