Browsing by Author "Lin, Jiann-T'suen"

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Enhanced light-harvesting capability by phenothiazine in ruthenium sensitizers with superior photovoltaic performance
(2012)
Yin, Jen-Fu
;
Chen, Jian-Ging
;
Lin, Jiann-T'suen
;
Bhattacharya, Dibyendu
;
Hsu, Ying-Chan
This paper reports on the design and synthesis of two new ruthenium dyes [Ru(dcbpy)(potip)(NCS)(2)] (JF-3, dcbpy 4,4'-dicarboxylic acid-2,2'-bipyridine, potip 2-(4-(10H-phenothiazin-10-yl)-5-octylthiophen- 2-yl)-1H-imidazo[4,5-f][1,10] phenanthroline, and [Ru(dcbpy)(dpotip)(NCS)(2)] (JF-4, dpotip = 2-(4-(N,N-diphenylamino)-5-octylthiophen-2-yl)-1H-imidazo[4,5-f][1,10] phenanthroline) that contain electron-donating phenothiazine-based or N,N-diphenylamino-based ancillary ligands. The ruthenium dye JF-3, in which an excellent electron-donating phenothiazine is incorporated, shows superior DSC performance (9.1%; compared to 8.8% for N3). A comparison of the electron-donating phenothiazine and N, N-diphenylamino groups utilized in the molecular architecture of ruthenium dyes demonstrates that the phenothiazine group efficiently increases the molar extinction coefficient of band II and also broadens that band in the UV-vis absorption spectrum, reduces device resistance, increases electron lifetime, and enhances power-conversion efficiency. This finding not only clarifies the significance of multifunctionalized design in the molecular architecture of ruthenium dyes, but also represents an alternative route for the introduction of an excellent electron-donating group for improving the light-harvesting characteristics of ruthenium dyes as well as DSC performance.
Nanographite/polyaniline composite films as the counter electrodes for dyesensitized solar cells
(2011)
Huang, Kuan-Chieh
;
Huang, Jen-Hsien
;
Wu, Chia-Hui
;
Liu, Chen-Yu
;
Chen, Hsin-Wei
Nanographite/polyaniline (NG/PANI) composite films were developed and characterized, and the performances of the dye-sensitized solar cells (DSSCs) employing these composite films as the counter electrode (CE) were evaluated in this study. The nanographite/aniline (NG/ANI) particle was firstly synthesized by a reflux method and served as the monomer for the electro-polymerization of the NG/PANI composite films. The surface modification of NG by ANI was confirmed by EDX mapping, TEM image, zeta-potential, and UV-Vis absorption measurements. The electro-polymerized NG/PANI composite films were characterized by Raman spectroscopy, XPS, and conducting-AFM, which verified the successful incorporation of NGs in the PANI films. The electro-catalytic activity of the NG/PANI composite film was evaluated using the positive-feedback mode of scanning electrochemical microscopy (SECM), by which a comparable heterogeneous rate constant (k(s)(0)) for the ferrocene/ ferrocenium (Fc/Fc(+)) redox pair was obtained and compared with that of a sputtered Pt. The DSSC employing the NG/PANI (20 mC cm(-2)) CE exhibited a higher short-circuit current density (J(SC)) but lower fill factor (FF), and gave a comparable power-conversion efficiency (eta) of 7.07%, as compared to that of a DSSC containing a sputtered Pt CE (eta = 7.19%).
Novel red and white PLED devices consisting of PVK blended with blue-emitting fluorene derivatives and carbazole dopants
(2006-11-01)
Lin, Hong-Cheu
;
Tsai, Chien-Min
;
Lin, Jiann-T'suen
;
Thomas, K. R. Justin
;
材料科學與工程學系
Highly fluorescent polymeric LEDs (PLEDs) utilizing blue-emitting FB fluorene derivatives (FBF14 and FBPh4) blended with PVK are demonstrated. Significant red shift of the emission from blue to red can be achieved by increasing the concentration of FB in the blend. The origin of emission was attributed to electromer (or electroplex) formation. Addition of Carb9 in the blend enhanced the electromer (or electroplex) formation, and red- or white-emission device with high brightness (3440 cd/m(2) for red; and 17368 cd/m(2) for white) was obtained. (c) 2006 Elsevier B.V. All rights reserved.
Soluble Narrow-Band-Gap Copolymers Containing Novel Cyclopentadithiophene Units for Organic Photovoltaic Cell Applications
(2009-04-15)
Li, Kuang-Chieh
;
Hsu, Ying-Chan
;
Lin, Jiann-T'suen
;
Yang, Chang-Chung
;
Wei, Kung-Hwa
Five novel conjugated copolymers (P1-P5) containing coplanar cyclopentadithiophene (CPDT) units (incorporated with arylcyanovinyl and keto groups in different molar ratios) were synthesized and developed for the applications of polymer solar cells (PSCs). Polymers P1-P5 covered broad absorption ranges from U-V to near infrared (400-900 nm) with narrow optical band gaps of 1.38-1.70 eV, which are compatible with the maximum solar photon reflux. Partially reversible p- and n-doping processes of P1-P5 in electrochemical experiments were observed, and the proper molecular design for highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) levels of P1-P5 induced the highest photovoltaic open-circuit voltage in the PSC devices, compared with those previously reported CPDT-based narrow-band-gap polymers. Powder X-ray diffraction (XRD) analyses suggested that these copolymers formed self-assembled pi-pi stacking and pseudobilayered structures. Under 100 mW/cm(2) of AM 1.5 white-light illumination, bulk hetero-junction PSC devices containing an active layer of electron donor polymers P1-P5 mixed with electron acceptor [6,6]-phenyl C(61) butyric acid methyl ester (PCBM) in the weight ratio of 1:4 were investigated. The PSC device containing P1 gave the best preliminary result with an open-circuit voltage of 0.84 V, a short-circuit current of 2.36 mA/cm(2), and a fill factor of 0.38, offering an overall power conversion efficiency (PCE) of 0.77% as well as a maximal quantum efficiency of 23% from the external quantum efficiency (EQE) measurements. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2073-2092, 2009
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
;
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.
Tunable Novel Cyclopentadithiophene-Based Copolymers Containing Various Numbers of Bithiazole and Thienyl Units for Organic Photovoltaic Cell Applications
(2009-06-09)
Li, Kuang-Chieh
;
Huang, Jen-Hsien
;
Hsu, Ying-Chan
;
Huang, Po-Ju
;
Chu, Chih-Wei
Six novel conjugated copolymers (P1-P6) containing coplanar cyclopentadithiophene (CPDT) units (incorporated with bithiazole/thienyl-based monomers) were synthesized and developed for the applications of polymer solar cells (PSCs). Copolymers P1-P6 covered broad absorption ranges from UV to near-infrared (400-800 nm) with narrow optical band gaps of 1.70-1.94 eV, which are compatible with the maximum solar photon reflux. Partially reversible p- and n-doping processes of P1-P6 in electrochemical experiments were observed. Compared with those previously reported CPDT-based narrow band gap polymers, the proper molecular design for HOMO/LUMO levels of P1-P6 induced relatively high photovoltaic open-circuit voltages in the PSC devices. Powder X-ray diffraction (XRD) analyses suggested that these copolymers formed highly self-assembled pi-pi stackings. Under 100 mW/cm(2) of AM 1.5 white-light illumination, bulk heterojunction PSC devices containing an active layer of electron donor copolymers P1-P6 blended with electron acceptor [6,6]-phenyl C(61) butyric acid methyl ester (PCBM) in the weight ratio of 1:1 were explored, and the external quantum efficiency (EQE) measurements showed a maximal quantum efficiency of 60%. The PSC device containing P4 in the weight ratio of 1:2 with PCBM gave the best preliminary result with an overall power conversion efficiency (PCE) of 3.04%, an open-circuit voltage of 0.70 V, a short-circuit current of 8.00 mA/cm(2), and a fill factor of 53.7%.