Rare Earth Oxide Nanolayer Coating on ZnO Nanowires in Dye-Sensitized Solar Cells

• Published in: Japanese Journal of Applied Physics 2013-10, Vol.52 (10), p.10MB26-10MB26-5
• Main Authors: Choi, Seok Cheol, Yun, Won Suk, Sohn, Sang Ho
• Format: Article
• Language: English
• Subjects: Coating; Electrochemical impedance spectroscopy; Nanostructure; Nanowires; Precursors; Rare earth metals; Solar cells; Zinc oxide
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.52.10MB26

Rare earth ion-modified ZnO nanowires were grown in solutions with precursors (Ce, Gd, La, and Y) and their effects on the photoelectrochemical properties of dye-sensitized solar cells (DSSCs) were investigated. Rare earth ion modifications yielded an increase in the lattice constant of ZnO nanowires, causing a widening of their energy bandgap. Photocurrent density vs photovoltage characteristics show that the photoelectrochemical properties increase in the order of Gd, Y, La, none, and Ce ion-modified ZnO nanowire-based DSSCs. From the data of the absorbance, incident to photon-to-current efficiency (IPCE) and electrochemical impedance spectroscopy (EIS), it was found that DSSCs with Ce ion-modified ZnO nanowires exhibit better device performance in terms of $V_{\text{oc}}$, $J_{\text{sc}}$, and efficiency, suggesting that the element of precursor is a key parameter in DSSCs. The experimental results can be explained in terms of the Burstein--Mott effects, vertical growth, and rare earth oxide coating effects of the ZnO nanowires.