Photovoltaic Behavior of Dye-sensitized Long TiO 2 Nanotube Arrays

• Published in: Bulletin of the Korean Chemical Society 2011, 32(11), , pp.4035-4040
• Main Authors: Kim, Sang-Mo, Kim, Hark-Jin, Kim, Yong-Joo, Lim, Goo-Il, Choi, Young-Sik, Lee, Wan-In
• Format: Article
• Language: English
• Subjects: 화학
• ISSN: 0253-2964; 1229-5949
• DOI: 10.5012/bkcs.2011.32.11.4035

Long TiO_2 nanotube (NT) arrays, prepared by electrochemical anodization of Ti foils, have been utilized as dye-adsorbing electrodes in dye-sensitized solar cells (DSCs). By anodizing for 1-24 hr and subsequent annealing, highly crystallized and tightly-adhered NT arrays were tailored to 11-150 μm lengths, ~90 nm innerpore diameter and ~30 nm wall thickness. I-V curves revealed that the photovoltaic conversion efficiency (η)was proportional to the NT length up to 36 μm. Beyond this length, the η was still steadily increased, though at a much lower rate. For example, an η of 5.05% at 36 μm was increased to 6.18% at 150 μm. Transient photoelectron spectroscopic analyses indicated that NT array-based DSCs revealed considerably higher electron diffusion coefficient (D_e) and life time (τ_e) than those with TiO_2 nanoparticles (NP). Moreover, the electron diffusion lengths (L_e) of the photo-injected electrons were considerably larger than the corresponding NT lengths in all the cases, suggesting that electron transport in NT arrays is highly efficient, regardless of tube length. KCI Citation Count: 4