Low temperature grown ZnO@TiO2 core shell nanorod arrays for dye sensitized solar cell application

• Published in: Journal of solid state chemistry Vol. 214; pp. 17 - 23
• Main Authors: Goh, Gregory Kia Liang, Le, Hong Quang, Huang, Tang Jiao, Hui, Benjamin Tan Tiong
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier Inc 01-06-2014; Elsevier
• Subjects: Applied sciences; Core shell; Cross-disciplinary physics: materials science; rheology; Dye sensitized solar cell; Energy; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanorod; Nanoscale materials and structures: fabrication and characterization; Natural energy; Other topics in nanoscale materials and structures; Photovoltaic conversion; Physics; Quantum wires; Solar cells. Photoelectrochemical cells; Solar energy; Solution method; Zinc oxide; Solution method; Zinc oxide; Nanorod; Dye sensitized solar cell; Core shell; Dye-sensitized solar cell; Short circuit currents; X ray microscopy; Core shell structure; Glass; Immersion; Aspect ratio; Dispersive spectrometry; Fill factor; Operating conditions; Solar cell; Thickness; Array; Transmission electron microscopy; Tin addition; Growth mechanism; Fluorine addition; Nanostructured materials; Nanomaterial synthesis
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2013.11.035

High aspect ratio ZnO nanorod arrays were synthesized on fluorine-doped tin oxide glasses via a low temperature solution method. By adjusting the growth condition and adding polyethylenimine, ZnO nanorod arrays with tunable length were successfully achieved. The ZnO@TiO2 core shells structures were realized by a fast growth method of immersion into a (NH4)2·TiF6 solution. Transmission electron microscopy, X-ray Diffraction and energy dispersive X-ray measurements all confirmed the existence of a titania shell uniformly covering the ZnO nanorod's surface. Results of solar cell testing showed that addition of a TiO2 shell to the ZnO nanorod significantly increased short circuit current (from 4.2 to 5.2mA/cm2), open circuit voltage (from 0.6V to 0.8V) and fill factor (from 42.8% to 73.02%). The overall cell efficiency jumped from 1.1% for bare ZnO nanorod to 3.03% for a ZnO@TiO2 core shell structured solar cell with a 18–22nm shell thickness, a nearly threefold increase.
The synthesis process of coating TiO2 shell onto ZnO nanorod core is shown schematically. A thin, uniform, and conformal shell had been grown on the surface of the ZnO core after immersing in the (NH4)2·TiF6 solution for 5–15min. [Display omitted]
•ZnO@TiO2 core shell nanorod has been grown on FTO substrate using low temperature solution method.•TEM, XRD, EDX results confirmed the existing of titana shell, uniformly covered rod's surface.•TiO2 shell suppressed recombination, demonstrated significant enhancement in cell's efficiency.•Core shell DSSC's efficiency achieved as high as 3.03%, 3 times higher than that of ZnO nanorods.