TY - JOUR
T1 - Self-Assembled Heteroepitaxial AuNPs/SrTiO3
T2 - Influence of AuNPs Size on SrTiO3 Band Gap Tuning for Visible Light-Driven Photocatalyst
AU - Tan, Kok Hong
AU - Lee, Hing Wah
AU - Chen, Jhih Wei
AU - Dee, Chang Fu
AU - Majlis, Burhanuddin Yeop
AU - Soh, Ai Kah
AU - Wu, Chung Lin
AU - Chai, Siang Piao
AU - Chang, Wei Sea
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/6/29
Y1 - 2017/6/29
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85022226704&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85022226704&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b02410
DO - 10.1021/acs.jpcc.7b02410
M3 - Article
AN - SCOPUS:85022226704
SN - 1932-7447
VL - 121
SP - 13487
EP - 13495
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 25
ER -