Browsing by Author "Tien, Cheng-Fang"

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Dye-sensitized solar cells based on agarose gel electrolytes using allylimidazolium iodides and environmentally benign solvents
(2013-02-28)
Hsu, Hsin-Ling
;
Tien, Cheng-Fang
;
Yang, Ya-Ting
;
Leu, Jihperng
;
材料科學與工程學系
Novel agarose gel electrolytes are prepared by allylimidazolium iodides-based ionic liquids and environmentally benign co-solvents (propylene carbonate (PC) and dimethyl sulfoxide (DMSO)) for dye-sensitized solar cells (DSSCs). Among 1-allyl-3-ethylimidadolium iodide (AEII), 1-allyl-3-propylimidazolium iodide (APII), 1-3-diallylimidazolium iodide (DAM, and 1-methyl-3-propylimidazolium iodide (MPII) ionic liquids, the agarose gel electrolyte containing AEII exhibits the best DSSC performance. The efficiency of the DSSC using the agarose gel electrolyte containing 1.5 M AEII and 0.65 wt% agarose is 5.89% with the highest I-3(-) diffusion coefficient of 7.7 x 10(-6) cm(2) s(-1). The performance of the AEII ionic liquid-based agarose gel electrolyte is comparable to the liquid electrolyte based on 3-methoxypropionitrile (MPN) (5.84%) under illumination at AM 1.5, 100 mW cm(-2). Moreover, the DSSC performance of the allylimidazolium iodides ionic liquid-based agarose electrolyte is determined by the interaction between ionic liquid and agarose, which affects the rigidity of the ion channels and the I-3(-) diffusion coefficient. (C) 2013 Elsevier Ltd. All rights reserved.
Effect of pore size/distribution in TiO2 films on agarose gel electrolyte-based dye-sensitized solar cells
(2014-06-01)
Hsu, Hsin-Ling
;
Tien, Cheng-Fang
;
Leu, Jihperng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
This study develops a simple method to change the distribution of the pore size in a TiO2 layer, using polyethylene glycol (PEG), while maintaining nearly the same surface area and porosity to clarify how large pores affect the performance of dye-sensitized solar cells (DSSCs). Specifically, a heating step at 100 A degrees C for a specific duration is added prior to PEG removal and TiO2 sintering at 400 A degrees C. This process transforms the role of the PEG from a surfactant to a pore generator (porogen) and forms larger pores, depending on the loading and aggregation time for the PEG to gain larger pores. The effect of larger pores in TiO2 films under 30 % PEG loading, on the performance of an agarose gel electrolyte-based DSSC, was further investigated using the ionic liquid, 1-allyl-3-ethylimidazolium iodide (AEII). The I-V characteristic and the electrochemical impedance spectroscopy analysis show that larger pores readily improve redox couple diffusion in a TiO2 porous electrode and modify the interface between electrolyte and TiO2. Using the optimized TiO2 film with larger pores (30 % PEG loading, 100 A degrees C/60 min), an efficiency of 7.43 % is achieved for the agarose gel electrolyte-based DSSC, which represents a 26.1 % improvement over TiO2 without the addition of PEG.