119th General Meeting of the KCS

Type Oral Presentation
Area Current Trends in Environmental and Energy Chemistry
Room No. 407호
Time THU 09:45-:
Code ENVR.O-4
Subject Charge transfer behaviour of vertically-aligned WO3 microdisc arrays for water oxidation
Authors 정혜원, 박현웅1,*
경북대학교 건설환경에너지공학부, Korea
1경북대학교 에너지공학부, Korea
Abstract One- to three-dimensional alignments of semiconductors on the micro- or nanoscale have been achieved to tailor their opto-physicochemical properties and improve their photoelectrochemical (PEC) performance. Here, we report for the first time the fabrication of vertically aligned, well-ordered WO3 microdisc arrays via an electrodeposition process on lithographically patterned indium tin oxide (ITO) substrates as well as their geometry-specific photoelectrochemical properties. The as-fabricated WO3 microdisc arrays exhibit enhanced light absorption as well as facilitated charge separation, leading to significantly higher PEC performance than that of WO3 films. A finite-difference time-domain simulation of a single WO3 microdisc indicates that the strong optical resonances occur particularly in the central part of the microdisc, leading to enhanced optical absorption. Time-resolved photoluminescence study further reveals that the averaged lifetime of charge carriers in a microdisc array is shorter than that in a film by ~60%. The reductively deposited Au particles are localized on the side of the microdisc and ITO substrate, which suggests that the photogenerated electrons are transferred to the same locations. In addition, the selective oxidative deposition of FeOOH particles on the top surface and side of a microdisc indicates hole transfer pathways at the same locations. This downward transfer of electrons and upward transfer of holes lead to efficient charge separation, and the radial direction appears to be the most preferred shortcut for the carriers inside the bulk of a microdisc.
E-mail hwj1012@gmail.com