Trap-state passivation of titania nanotubes by electrochemical doping for enhanced photoelectrochemical performance

Lok Kun Tsui; Mikiko Saito; Takayuki Homma; Giovanni Zangari

doi:10.1039/c4ta05620e

Trap-state passivation of titania nanotubes by electrochemical doping for enhanced photoelectrochemical performance

Lok Kun Tsui, Mikiko Saito, Takayuki Homma, Giovanni Zangari^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

40 Citations (Scopus)

Abstract

TiO₂ nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO₂ nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM. This journal is

Original language	English
Pages (from-to)	360-367
Number of pages	8
Journal	Journal of Materials Chemistry A
Volume	3
Issue number	1
DOIs	https://doi.org/10.1039/c4ta05620e
Publication status	Published - 2015 Jan 7

ASJC Scopus subject areas

Chemistry(all)
Renewable Energy, Sustainability and the Environment
Materials Science(all)

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10.1039/c4ta05620e

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abstract = "TiO2 nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO2 nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM. This journal is",

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AU - Tsui, Lok Kun

AU - Saito, Mikiko

AU - Homma, Takayuki

AU - Zangari, Giovanni

PY - 2015/1/7

Y1 - 2015/1/7

N2 - TiO2 nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO2 nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM. This journal is

AB - TiO2 nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO2 nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM. This journal is

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Trap-state passivation of titania nanotubes by electrochemical doping for enhanced photoelectrochemical performance

Abstract

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