Emin, S.; Fanetti, M.; Abdi, F.F.; Lisjak, D.; Valant, M.; van de Krol, R.; Dam, B.: Photoelectrochemical Properties of Cadmium Chalcogenide-Sensitized Textured Porous Zinc Oxide Plate Electrodes. ACS Applied Materials & Interfaces 5 (2013), p. 1113-1121
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.