Photoelectrochemical Properties of Cadmium Chalcogenide-Sensitized Textured Porous Zinc Oxide Plate Electrodes
journal contributionposted on 2013-02-13, 00:00 authored by Saim Emin, Mattia Fanetti, Fatwa F. Abdi, Darja Lisjak, Matjaz Valant, Roel van de Krol, Bernard Dam
We report the photoelectrochemical (PEC) performance of textured porous ZnO and CdX-coated ZnO films (X = S, Se). Porous ZnO films were grown with a platelike morphology on F-doped SnO2 (FTO) substrates. The growth of ZnO films involves a two-step procedure. In the first step, we electrochemically grew simonkolleite (Zn5(OH)8Cl2·H2O) plate films. Annealing of the simonkolleite at 450 °C results in textured porous ZnO films. The as-obtained porous ZnO electrodes were then used in PEC studies. To increase the light-harvesting efficiency, we sensitized these ZnO electrodes with CdS and CdSe quantum dots, using the so-called “successive ion layer adsorption and reaction (SILAR) method”. As expected, the photocurrent density systematically increases when going from ZnO to ZnO/CdS to ZnO/CdSe. The highest photocurrent, ∼3.1 mA/cm2 at 1.2 V vs RHE, was obtained in the CdSe-sensitized ZnO electrodes, because of their enhanced absorption in the visible range. Additionally, quantum efficiency values as high as 90% were achieved with the textured porous ZnO films. These results demonstrate that both CdS and CdSe-sensitized textured porous ZnO electrodes could be potentially useful materials in light-harvesting applications.