Commandeur, Daniel, Brown, Grant, Mcnulty, Peter, Dadswell, Christopher, Spencer, John and Chen, Qiao (2019) Yttrium doped ZnO nanorod arrays for increased charge mobility and carrier density for enhanced solar water splitting. The Journal of Physical Chemistry C. ISSN 1932-7455

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Abstract

An innovative procedure is presented, when for the first time, yttrium doped ZnO vertically aligned nanorods have been synthesized using a unique rapid microwave assisted method. In comparison with pristine ZnO NRs, the Y-doped samples present more favourable morphology along with reduced crystallinity due to substitutional defects, YZn. The Y acted as a shallow donor type defect, leading to an 80% increase in dopant density, to 1.36×1018 cm−2 in the 0.15% Y sample. The transmission line model was used to analyse the transport properties. It was found that a 1000-fold increase in conductivity and electron mobility was achieved by doping 0.15% Y, resulting in a high density of donors which fill charge traps. Meanwhile, a significant improvement in conductivity was accompanied by greater electron hole recombination and band gap reduction. Analysis of photoluminescence spectra reveals the effect of Y doping on native point defects, initially reducing Zn2+ vacancies by filling with YZn, followed by the reduction of O2- vacancies with interstitial doping at higher Y concentration. With a fine balance of superior conductivity and charge recombination rate, the photocatalytic water splitting performance was optimised achieving photocurrent of 0.84 mA cm−2 at 1.23 VRHE with 0.1% Y doping. This corresponded to a 47% enhancement in photoconversion efficiency compared to the pristine sample.

Item Type:	Article
Schools and Departments:	School of Life Sciences > Chemistry
Subjects:	Q Science > QD Chemistry > QD0450 Physical and theoretical chemistry > QD0701 Photochemistry
Depositing User:	Qiao Chen
Date Deposited:	17 Jul 2019 10:39
Last Modified:	17 Jul 2019 10:45
URI:	http://sro.sussex.ac.uk/id/eprint/84948

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