Browsing by Author "Hsieh, Kuo-Huang"

Now showing 1 - 9 of 9

Cesium carbonate as a functional interlayer for polymer photovoltaic devices
(2008-05-15)
Chen, Fang-Chung
;
Wu, Jyh-Lih
;
Yang, Sidney S.
;
Hsieh, Kuo-Huang
;
Chen, Wen-Chang
The device characteristics of polymer solar cells with cesium carbonate (Cs(2)CO(3)) as an electron-injection interlayer have been investigated. It is found that the insertion of Cs(2)CO(3) at the cathode interface improves the device power conversion efficiency from 2.3% to 3.1%. In order to further understand the mechanism, the interfacial interaction between the active organic layer and the cathode was studied by x-ray photoemission spectroscopy (XPS). The results of XPS measurement indicate the fact that a portion of electrons transfer from the interlayer into the organic layer, resulting in n-type doping. The n-doping effect enhances the efficiency of electron injection and collection. Further, the maximum open-circuit voltage (V(oc)) was determined from its temperature dependence. For the device with Cs(2)CO(3), the maximum V(oc) is extremely close to the corresponding value of the energy difference between the highest occupied molecular orbital of the electron donor and the lowest unoccupied molecular orbital of the electron acceptor, suggesting a better Ohmic contact. All evidences indicated that Cs(2)CO(3) is a promising candidate as an interlayer to improve the device performance. (C) 2008 American Institute of Physics.
Effect of Bridging Groups on Sulfonated Poly(imide-Siloxane) for Application in Proton Exchange Membrane
(2010-04-01)
Lee, Chi-Hung
;
Chen, Jia-Ru
;
Shiu, Hung-Wei
;
Ho, Ko-Shan
;
Wu, Shinn-Dar
A series of six-membered sulfonated poly(imide-siloxane)s (SPIs) was synthesized using 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), aminopropyl-terminated polydimethylsiloxane (PDMS) 2,2-benzidinedisulfonic acid (BDSA), as the sulfonation target diamine groups, and various nonsulfonated diamine monomers behaving as bridging groups. The structure-property relationship of SPI-SXx membranes is discussed in detail according to the chemical structure of the various nonsulfonated diamines of the SPI-SXx membranes from the viewpoints of proton conductivity, ion exchange capacity (IEC), and membrane properties (water uptake and membrane swelling) at equal PDMS content SPI-SXx. The PDMS was introduced to enhance the proton conductivity and water uptake attributed from the high flexibility of the siloxane segments. The conductivity and water uptake of angled SPI-SXm and oxydianiline-based SPI-SX membranes (SPI-SXO) are greater than those prepared from diaminodiphenylmethane-based SPI-SX membranes (SPI-SXD) at a given IEC. These differences resulted from the increased number of entanglements of the SPI-SXx membrane. The SPI-SXD showed almost isotropically dimensional changes with the increase in water uptake, and the volume were slightly smaller than those estimated from the additivity rule. Free volume in the SPI-SXx increased with the increase in bulky irregular packing in nonsulfonated segments, which augmented the water uptake and, in turn, the conductivity of the polymer. With the increase in temperature, conductivity increased more rapidly in SPI-SXx than in Nafion 117. Microscopic analyses revealed that these smaller (<10 nm) and well-dispersed hydrophilic domains contribute to better proton conducting properties. The new sulfonated poly(imide-siloxane) s have proved to be a possible candidate as the polymer electrolyte membrane for polymer electrolyte fuel cells (PEFCs) and direct methanol fuel cells (DMFCs). [DOI: 10.1115/1.3200906]
Influence of Sulfonationity of Epoxy-Based Semi-Interpenetrating Polymer Networks of Sulfonated Polyimides as Proton Exchange Membranes on the Performance of Fuel Cell Application
(2010-04-01)
Wang, Yen-Zen
;
Ho, Ko-Shan
;
Wu, Shinn-Dar
;
Hsieh, Kuo-Huang
;
Lee, Chi-Hung
A novel epoxy-based semi-interpenetrating polymer networks membrane (SPIX-EP40) as the proton exchange membrane was prepared by a flexible epoxy network with sulfonated polyimide. A series of sulfonated polyamic acid (SPAA) were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-benzidinedisulfonic acid (BDSA) and non-sulfonated diamines, such as 4,4'-diaminodiphenyl sulfone. Solid-state (13)C nuclear magnetic resonance spectra and Fourier transform infrared spectroscopy were used to verify the synchronization of the imidization of SPAA and the crosslinking reactions of epoxy. The sulfonationity of the copolymers was regulated through a variation in the molar ratio of BDSA to diamine. These membranes owned a good thermal stability and exhibited high proton conductivity that was measured as a function of temperature. The resulting SPI0.7-EP40 and SPI0.8-EP40, at 100% relative humidity, displayed proton conductivities higher than those of Nafion (R) 117. The membranes displayed higher conductivities than Nafion (R) membranes because of owning higher activational energies and higher ion exchange capacities. An isotropic swelling phenomenon in water was found for the membrane. From the results of water uptake and the microstructure analyses using transmission electron microscopy (TEM) on different sulfonated levels, it was found that the number of water clusters in SPIX-EP40 membranes increased as the increasing water uptake and the size of water cluster were changed with the sulfonation levels. TEM confirmed the widespread and well-connected hydrophilic domains, demonstrating the presence of the favorable proton-transporting performances of the SPIX-EP40 membrane. [DOI: 10.1115/1.3177383]
PMSE 594-New class of biomaterials made from natural building blocks: Saccharide-peptide hybrid copolymers
(2006-09-10)
Hsieh, Kuo-Huang
;
Lin, Shih-Pin
;
Han, Jin-Lin
;
Yeh, Jen-Taut
;
Chang, Feng-Chih
Polymer photovoltaic devices with highly transparent cathodes
(2008-12-01)
Chen, Fang-Chung
;
Wu, Jyh-Lih
;
Hsieh, Kuo-Huang
;
Chen, Wen-Chang
;
Lee, Shih-Wei
In this paper, we demonstrate semi-transparent polymer solar cells employing a transparent cathode configuration, made of cesium carbonate (Cs2CO3)/silver (Ag)/indium tin oxide (ITO), which exhibited high transmittance in the visible regime. The device performance of the semi-transparent devices was significantly improved after thermal post-annealing and incorporating an Al counter-electrode (CE) grid. Further, the short-circuit current density increased almost linearly with the incident light intensity, suggesting efficient charge collection ability of the transparent cathode. Overall, the semi-transparent polymer solar cell exhibits a remarkable power conversion efficiency of 2.09%. (C) 2008 Elsevier B.V. All rights reserved.
Removal of Hg(2+) from Aqueous Solution Using a Novel Composite Carbon Adsorbent
(2009-05-15)
Chang, Yu-Hsin
;
Hsieh, Kuo-Huang
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg(2+)) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg(2+) ions by the GCA. The Hg(2+) adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg(2+) adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg(2+) increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg(2+) adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg(2+) adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg(2+) ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg(2+) removal at low pH values. The Hg(2+) absorbed beads of the GCA can be effectivelY regenerated and reused using H(2)SO(4). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009
Removal of Hg2+ from Aqueous Solution Using a Novel Composite Carbon Adsorbent
(2009-05-15)
Chang, Yu-Hsin
;
Hsieh, Kuo-Huang
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg2+) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg2+ ions by the GCA. The Hg2+ adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg2+ adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg2+ increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg2+ adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg2+ adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg2+ ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg2+ removal at low pH values. The Hg2+ absorbed beads of the GCA can be effectivelY regenerated and reused using H2SO4. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009
Synthesis and characterization of well-dispersed multi-walled carbon nanotube/low-bandgap poly(3,4-alkoxythiophene) nanocomposites
(2010-08-01)
Liu, Cheng-Dar
;
Shu, De-Yu
;
Tsao, Ching-Ting
;
Han, Jin-Lin
;
Tsai, Feng-Yu
In this study, we prepared nanocomposites of multi-walled carbon nanotubes (MWCNTs) and low-energy-bandgap conjugated polymers incorporating 3,4-alkoxythiophene monomers. Poly(3,4-dihexyloxythiophene) (PDHOT) and poly(3,4-dimethoxythiophene-co-3,4-dihexyloxythiophene) [P(DMOT-co-DHOT)] have relatively low-energy-bandgaps (ca. 1.38 and 1.34 eV, respectively), determined from the onsets of absorbances in their UV-Vis spectra, because of the electron-donating effects of their alkoxy groups. MWCNTs have poor solubility in common organic solvents; after surface modification with alkyl side chains using the Tour reaction, however, the p-hexylaniline modified MWCNT derivative (MWCNT-HA) was readily dispersed in CHCl(3) and could be mixed with the low bandgap polymers. Scanning electron microscopy images revealed that MWCNT-HA was dispersed well in each polythiophene derivative; only a few MWCNT-HA bundles could be observed at a high MWCNT-HA content (>= 20 wt.%). The electrical conductivities of the MWCNTs/PDHOT composites were dependent on their MWCNT content, reaching 16 S/cm at 30 wt.% MWCNT-HA. We suspect that the two hexyloxy chains of PDHOT enhanced its solubility and allowed it to wrap around the surfaces of the MWCNTs more readily. (C) 2010 Elsevier Ltd. All rights reserved.
Volume shrinkages and mechanical properties of various fiber-reinforced hydroxyethyl methacrylate-polyurethane/unsaturated polyester composites
(2007-08-19)
Lin, Shih-Pin
;
Shen, Jia-Hong
;
Han, Jin-Lin
;
Lee, Ya-Rong
;
Yeh, Jen-Taut