Self-Assembled Heteroepitaxial AuNPs/SrTiO3: Influence of AuNPs Size on SrTiO3 Band Gap Tuning for Visible Light-Driven Photocatalyst

Kok Hong Tan, Hing Wah Lee, Jhih Wei Chen, Chang Fu Dee, Burhanuddin Yeop Majlis, Ai Kah Soh, Chung Lin Wu, Siang Piao Chai, Wei Sea Chang

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Self-assembled heteroepitaxial offers tremendous opportunity to tailor optical and charge transport properties in noble metal-semiconductor interface. Here, we incorporated gold nanoparticles (AuNPs) onto the {001} facets of semiconductor strontium titanate, SrTiO3 (STO), by means of heteroepitaxial approach to investigate the band gap tuning and its effect of photoresponse. We demonstrate that the Fermi energy level of the system can be tuned by controlling the AuNPs size. X-ray photoelectron spectroscopy (XPS) shows that the energy difference between Sr3d and Au4f core levels measured in the AuNPs/STO (100) heterojunction increases from 47.90 to 49.26 eV with decreasing AuNPs size from 65 to 16 nm, respectively. Hence, the Fermi energy level was shifted toward the conductive band of STO (100), and the system charge transfer efficiency was improved. It was also found that smaller AuNPs sizes exhibited a higher photoactivity as the result of the band gap narrowing effect. Photoactivity was improved by broadening the catalyst absorption spectrum to the visible light region. This study provides a basic understanding of the photoelectrochemistry of metal-semiconductor heterostructure for visible light-energy conversion.

Original languageEnglish
Pages (from-to)13487-13495
Number of pages9
JournalJournal of Physical Chemistry C
Volume121
Issue number25
DOIs
Publication statusPublished - 2017 Jun 29

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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