Browsing by Author "Fang, Hsiao-Ping"

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Applications of novel dithienothiophene- and 2,7-carbazole-based conjugated polymers with surface-modified ZnO nanoparticles for organic photovoltaic cells
(2011-05-31)
Fang, Hsiao-Ping
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Chiang, I-Hung
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Chu, Chih-Wei
;
Yang, Chang-Chung
;
Lin, Hong-Cheu
Two kinds of novel conjugated polymers containing 2,7-carbazole, thiophene, and fused-dithienothiophene rings as backbones bearing acid-protected and benzoic acid pendants (PC1 and PC2, respectively) were utilized for organic solar cell applications. The absorption spectra of these polymers (in both solutions and solid films) showed an absorption range at 300-580 nm. Furthermore, ZnO nanoparticles were synthesized and surface-modified with pyridyl surfactants (ZnOpy) to be ca. 3-4 nm. The pyridyl surfactants of ZnOpy nanoparticles (as electron acceptors to partially replace expensive electron acceptor PCBM) not only induce supramolecular interactions with benzoic acid pendants of polymer PC2 via H-bonds, but also enhance the homogeneous dispersions of ZnOpy nanoparticles in polymer PC2. Thus, the ternary systems of PC1-N2/ZnOpy/PCBM in weight ratios of 1:0.05:1 and 1:0.1:1 were investigated in bulk heterojunction polymer solar cells (PSCs). Under the standard illumination of AM 1.5, 100 mW/cm(2), the best power conversion efficiency (PCE) of the PSC cell containing a polymer blend of PC2/ZnOpy/PCBM = 1:0.05:1 reached PCE = 0.55%, with J(sc) = 2.11 mA/cm(2), V(oc) = 0.88 V, and FF = 29.4%. (C) 2011 Elsevier B.V. All rights reserved.
Naked eye and fluorescent detections of Hg2+ ions and Cysteine via J-aggregation and deaggregation of a perylene bisimide derivative
(2014-04-01)
Fang, Hsiao-Ping
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Shellaiah, Muthaiah
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Singh, Ashutosh
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Raju, Mandapati V. Ramakrishnam
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Wu, Yen-Hsing
Selective naked eye and fluorescent sensor responses of a 1,6,7,12-tetra(4-tert-butylphenoxy)perylene-3,4:9,10-tetracarboxylic acid bisimide (PBI) derivative are reported for the first time toward Hg2+ ions and Cysteine (Cys) via J-aggregation and deaggregation mechanisms. The J-aggregation and deaggregation of PBI induced by Hg2+ and Cys were well established by UV-vis/PL and H-1 NMR titrations. The 1:1 stoichiometry of PBI-Hg2+ and Cys-Hg2+/PBI ensembles were elucidated from the jobs plots based on their UV-vis spectral changes. The linear complex formation by PBI-Hg2+ ensemble was confirmed through FT-IR and H-1 NMR spectral studies and well supported by its reversible nature upon the addition of pentamethyl diethylene triamine (PMDTA). The positive cooperativities of Hg2+ and Cys (with PBI) in PBI-Hg2+ and Cys-Hg2+/PBI ensembles were evidenced from the Hill plots based on their fluorescence binding isotherms. The detection limits of Hg2+ ions and Cys were calculated as 36.6 and 91.3 nM, respectively, by standard deviations and linear fittings of their Stern-Volmer (KSV) constants and relative fluorescence intensity changes, respectively. Furthermore, the sensor properties of PBI were well investigated by KSV constants, pH values, time effects, and time resolved photoluminescence (TRPL) spectra. (C) 2013 Elsevier B.V. All rights reserved.
Synthesis and study of novel supramolecular nanocomposites containing aryl-imidazo-phenanthroline-based metallo-polymers (H-donors) and surface-modified ZnO nanoparticles (H-acceptors)
(2013-01-07)
Fang, Hsiao-Ping
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Wu, Yen-Hsing
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Lin, Hong-Cheu
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材料科學與工程學系
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Department of Materials Science and Engineering
Four novel metallo-polymers (P1-P4) containing aryl-imidazo-phenanthrolines (AIP) ligands (incorporated with phenyl and fused-thiophene cores) were synthesized and characterized. Interestingly, P1-P4 exhibited electrochromism during the oxidation processes of cyclic voltammogram studies. In addition, P1-P4 were blended with surface-modified pyridyl-ZnO nanoparticles (ZnOpy as proton acceptors) to form nanocomposites, where P3-P4 were functionalized with carboxylic acid pendants (as proton donors) on the polymer backbones to study for the H-bonded effects on surface-modified ZnOpy nanoparticles. In order to investigate the nanocomposites containing metallo-polymers P1-P4 and surface-modified ZnOpy nanoparticles, nanocomposites P1-P4/ZnOpy were characterized by UV-visible (UV) absorption spectra, Fourier transform infrared (FT-IR), photoluminescence (PL) spectra, time-resolved photoluminescence decays, X-ray diffraction (XRD) measurements, and transmission electron microscopy (TEM) analyses. In contrast to nanocomposites P1/ZnOpy and P2/ZnOpy, higher crystallinities with a distinct layered-structure of H-bonded nanocomposites P3/ZnOpy and P4/ZnOpy in XRD measurements were induced by the introduction of surface-modified ZnOpy nanoparticles to metallopolymers P3 and P4, correspondingly. Furthermore, due to the supramolecular interactions of surface-modified ZnOpy nanoparticles with metallo-polymers P3-P4, TEM images verified that ZnOpy nanoparticles were more homogeneously distributed in nanocomposites P3-P4/ZnOpy (with H-bonds) than those in P1-P2/ZnOpy (without H-bonds), respectively. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis of metal-free organic dyes containing tris(dodecyloxy)phenyl and dithienothiophenyl units and a study of their mesomorphic and photovoltaic properties
(2013-03-04)
Shellaiah, Muthaiah
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Fang, Hsiao-Ping
;
Lin, Yu-Ling
;
Hsu, Ying-Chan
;
Lin, Jiann-T'suen
In this study we synthesized three metal-free organic dyes (Cpd11, Cpd16, and Cpd22) featuring 3,4,5-tris(dodecyloxy)phenyl and cyanoacrylic acid moieties as electron-donor and electron-acceptor/anchoring units, respectively, linked through various dithienothiophenyl conjugated spacers. Cpd16 exhibits mesomorphic properties, confirmed through polarizing optical microscopy, differential scanning calorimetly, and X-ray diffraction (XRD), due to the appropriate ratio of the lengths of its flexible chain to its rigid core. Molecular modeling of Cpd16, and its d-spacing determined from XRD data, verified the existence of a tilt angle in the SmC phase. Among these metal-free organic dyes, a dye-sensitized solar cell incorporating Cpd16 exhibited the best performance, presumably because of its better packing and its mesomorphic properties; the power conversion efficiency was 3.72% (V-oc=0.58 V; J(sc)=9.98 mA cm(-2); FF=0.65) under simulated AM 1.5 irradiation (100 mW cm(-2)). (c) 2013 Elsevier Ltd. All rights reserved.
Synthesis of novel dithienothiophene- and 2,7-carbazole-based conjugated polymers and H-bonded effects on electrochromic and photovoltaic properties
(2012-12-15)
Fang, Hsiao-Ping
;
Lin, Jia-Wei
;
Chiang, I-Hung
;
Chu, Chih-Wei
;
Wei, Kung-Hwa
Three kinds of dithienothiophene/carbazole-based conjugated polymers (P1P3), which bear acid-protected and benzoic acid pendants in P2 and P3, respectively, were synthesized via Suzuki coupling reaction. Interestingly, P1P3 exhibited reversible electrochromism during the oxidation processes of cyclic voltammogram studies, and P3 (with H-bonds) revealed the best electrochromic property with the most noticeable color change. According to powder X-ray diffraction (XRD) analysis, these polymers exhibited obvious diffraction features indicating bilayered packings between polymer backbones and p-p stacking between layers in the solid state. Compared with the XRD data of P2 (without H-bands), H-bonds of P3 induced a higher crystallinity in the small-angle region (corresponding to a higher ordered bilayered packings between polymer backbones), but with a similar crystallinity in the wide angle region indicating a comparable p-p stacking distance between layers. Moreover, based on the preliminary photovoltaic properties of PSC devices (P1P3 blended individually with PCBM acceptor in the weight ratio of 1:1), P3 (with H-bonds) possessed the highest power conversion efficiency of 0.61% (with Jsc = 2.26 mA/cm2, FF = 29.8%, and Voc = 0.9 V). In contrast to P2 (without H-bands), the thermal stability, crystallinity, and electrochromic along with photovoltaic properties of P3 were generally enhanced due to its H-bonded effects. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012