Evaluation of electroactive surface area of CdSe nanoparticles on wide bandgap oxides (TiO2, ZnO) by cadmium underpotential deposition

• Published in: Electrochemistry communications Vol. 72; pp. 176 - 180
• Main Authors: Malashchonak, M.V., Streltsov, E.A., Ragoisha, G.A., Dergacheva, M.B., Urazov, K.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2016
• Subjects: CdSe quantum dots; Electroactive surface area; Quantum dot-sensitized solar cells; TiO2; Underpotential deposition; ZnO; Electroactive surface area; ZnO; Quantum dot-sensitized solar cells; Underpotential deposition; CdSe quantum dots; TiO2
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2016.10.004

Underpotential deposition of cadmium was applied for in situ determination of electroactive surface area (ESA) of CdSe nanoparticles deposited by successive ionic layer adsorption and reaction (SILAR) onto TiO2 nanotubes and porous ZnO films. The sensitized photocurrent on CdSe/TiO2 and CdSe/ZnO electrodes was normalized for ESA, and the ESA normalized photocurrent was compared with the photocurrent normalized for geometric area of electrodes. Significantly different types of dependences were observed with the two methods of normalization for the surface area. The efficiency of CdSe as sensitizer appeared to be higher on ZnO when normalized for CdSe ESA, though the photocurrent normalized for geometric area of electrode was an order of magnitude higher on CdSe/TiO2 electrodes. Also, notable maxima in the photocurrent dependences on the number of SILAR cycles disappeared after the normalization for the ESA, showing a gradual increase in the efficiency of the sensitizer unit surface area with the number of SILAR cycles. This simple experimental procedure can be a helpful tool in the investigation and development of quantum dot-sensitized solar cells. [Display omitted] •In situ evaluation of electroactive surface area of CdSe on TiO2 and ZnO is proposed.•The method applies the selective underpotential deposition of cadmium on CdSe.•Photocurrents were normalized for the electroactive and geometric surface areas.•Discrimination between sensitizer efficiency and surface area effects in the photocurrent.