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GROWTH TIME DEPENDENCE ON PHOTOELECTROCHEMICAL PROPERTY of ZINC OXIDE NANORODS PREPARED by HYDROTHERMAL SYNTHESIS
Author(s)
Rattanawarinchai, Prapakorn
Jessadaluk, Sukittaya
Chananonnawathorn, Chanunthorn
Horprathum, Mati
Klamchuen, Annop
Date Issued
December 1, 2018
Type
Article
Abstract
Here, the dependence of growth time on the growth behavior, morphology and photoelectrochemical (PEC) properties of ZnOnanorods (ZnO-NRs) as a photoanode are demonstrated. Vertical-aligned ZnO-NRs with c-axis perpendicular to substrate were accomplished via seed-assisted hydrothermal technique at the growth time varying between 0.5 and 24h. Growth behaviors of ZnO-NRs can be described into three regimes, which consist of the nucleation stage, ZnO-NRs growth and saturation growth, respectively. ZnO nanoparticles (NPs) corresponding to the nucleation site occur at the growth time below 1h. Afterward, the growth regime of ZnO-NRs, which originated from the competition between the vertical and the lateral growth, is clearly observed, and leads to increase in length and diameter. The whole growth of ZnO-NRs is terminated after 16h, attributed to low amount of Zn 2+ and OH - supplied from growth solution. PEC measurement reveals the fast solar response and high photostability of ZnO-NRs. Additionally, the photoconversion efficiency (η) improves with the growth time of 4h and degrades for longer time due to the change of total surface area. The maximum η of 0.13% at 0.63V RHE is obtained for the growth time of 4h. Our results highlight that the growth time plays a crucial role in controlling growth behavior and the total surface area directly related with the PEC properties of ZnO-NRs.
Citation
Surface Review and Letters, 25, 2018