Imperial College London
Portrait Picture

Dr Steph Pendlebury

Faculty of Engineering

IMSE Institute Manager
 
 
 
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Contact

 

+44 (0)20 7594 0901s.pendlebury Website

 
 
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Location

 

Level 2 Office, Central LibraryAbdus Salam LibrarySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ma:2014:10.1039/C4SC00469H,
author = {Ma, Y and Pendlebury, SR and Reynal, A and Le, Formal F and Durrant, JR},
doi = {10.1039/C4SC00469H},
journal = {Chemical Science},
pages = {2964--2973},
title = {Dynamics of photogenerated holes in undoped BiVO4 photoanodes for solar water oxidation},
url = {http://dx.doi.org/10.1039/C4SC00469H},
volume = {5},
year = {2014}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The dynamics of photogenerated holes in undoped BiVO4 photoanodes for water splitting were studied using transient absorption spectroscopy, correlated with photoelectrochemical and transient photocurrent data. Transient absorption signals of photogenerated holes were identified using electron/hole scavengers and applied electrical bias in a complete photoelectrochemical cell. The yield of long-lived (0.1-1 s) photogenerated holes is observed to correlate as a function of applied electrical bias with the width of the space charge layer, as determined by electrochemical impedance spectroscopy. The transient absorption decay time constant of these long-lived holes is also observed to be dependent upon the applied bias, assigned to kinetic competition between water oxidation and recombination of these surface accumulated holes with bulk electrons across the space charge layer. The time constant for this slow recombination measured with transient absorption spectroscopy is shown to match the time constant of back electron transfer from the external circuit determined from chopped light transient photocurrent measurements, thus providing strong evidence for these assignments. The yield of water oxidation determined from these measurements, including consideration of both the yield of long-lived holes, and the fraction of these holes which are lost due to back electron/hole recombination, is observed to be in good agreement with the photocurrent density measured for BiVO4 photoanodes as a function of bias under continuous irradiation. Overall these results indicate two distinct recombination processes which limit photocurrent generation in BiVO4 photoanodes: firstly rapid ([less-than-or-equal]microseconds) electron/hole recombination, and secondly recombination of surface-accumulated holes with bulk BiVO4 electrons. This second 'back electron transfer' recombination occurs on the milliseconds-seconds timescale, and is only avoided at strong anodic biases where the potentia
AU  - Ma,Y
AU  - Pendlebury,SR
AU  - Reynal,A
AU  - Le,Formal F
AU  - Durrant,JR
DO  - 10.1039/C4SC00469H
EP  - 2973
PY  - 2014///
SN  - 2041-6520
SP  - 2964
TI  - Dynamics of photogenerated holes in undoped BiVO4 photoanodes for solar water oxidation
T2  - Chemical Science
UR  - http://dx.doi.org/10.1039/C4SC00469H
UR  - http://hdl.handle.net/10044/1/26386
VL  - 5
ER  -
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