Browsing by Author "Li, Lu Lin"

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Anodic TiO2 Nanotube Arrays for Dye-Sensitized Solar Cells Characterized by Electrochemical Impedance Spectroscopy
(2012-12-01)
Wu, Hui Ping
;
Li, Lu Lin
;
Chen, Chien Chon
;
Diau, Eric Wei Guang
;
土木工程學系
This paper reports on the microstructure of anodic titanium oxide (TiO2) and its use in a dye-sensitized solar cell (DSSC) device. When voltages of 60 V were applied to titanium foil for 2 hr under 0.25 wt% NH4F + 2 vol% H2O+C2H4(OH)(2), TiO2 with a nanotube structure was formed. The film, which had a large surface area, was used as an electron transport film in the DSSC. The DSSC device had a short-circuit current density (J(sc)) of 12.52 mA cm(-2), a fill factor (FF) of 0.65, an open-voltage (V-oc) of 0.77 V, and a photocurrent efficiency of 6.3% under 100% AM 1.5 light. The internal impedance values under 100%, 64%, 11%, and 0% (dark) AM 1.5 light intensities were measured and simulated using the electrical impedance spectroscopy (EIS) technique. The impedance characteristics of the DSSC device were simulated using inductors, resistors, and capacitors. The Ti/TiO2, TiO2/Electrolyte, electrolyte, and electrolyte/ (Pt/ITO) interfaces were simulated using an RC parallel circuit, and the bulk materials, such as the Ti, ITO and conducting wire, were simulated using a series of resistors and inductors. The impedance of the bulk materials was simulated using L-0+R-0+R-b, the impedance of the working electrode was simulated using (C-1//R-1)//(R-a+(C-2//R-2), the electrolyte was simulated using C-3//R-3, and the counter electrode was simulated using C-4//R-4. (C) 2012 Elsevier Ltd and Techna Group Sri. All rights reserved.
Enhanced Efficiency of Dye-Sensitized Solar Cells Using Anodic Titanium Oxide Nanotube Arrays
(2009)
Chen, Chien Chon
;
Jehng, Wern Dare
;
Li, Lu Lin
;
Diau, Eric Wei-Guang
;
應用化學系
This paper concerns the microstructure of the anodic titanium oxide (ATO, TiO(2)) nanotube (NT) and its use for the dye-sensitized solar cell (DSSC) device. The ATO length was controlled by various electrolytes and anodic time at various constant applied voltages. The lengths of the NTs at 0.3-0.5 and 0.9-22 mu m were controlled by 0.5 vol % HF and 0.58 wt % KF aqueous solutions for varied periods of anodization (1-24 h). The 0.5 wt % NH(4)F electrolyte in ethylene glycol can produce 4-41 mu m for varied periods of anodization (0.5-8 h). ATO made of 0.3 (0.5 vol % HF), 12 (0.5 wt % KF), and 18 mu m (0.5 wt % NH(4)F) was used for the DSSC anode; the best cell performance attained 0.13, 3.76, and 6.18%. The DSSC made of 18 mu m ATO has a short-circuit current density (J(sc)) of 13.45 mA/cm(2), a fill factor of 0.64, an open voltage (V(oc)) of 0.72 V, and a photocurrent efficiency of 6.18% under an air mass 1.5 illumination test.