Browsing by Author "Lu, Kuang-Lieh"

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An Unprecedentedly Huge Square-Grid Copper(II)-Organic Framework Material Built from a Bulky Pyrene-Derived Elongated Cross-Shaped Scaffold
(2009-09-21)
Tsai, Chen-Chuan
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Luo, Tzuoo-Tsair
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Yin, Jen-Fu
;
Lin, Hong-Cheu
;
Lu, Kuang-Lieh
A new bulky pyrene-derived elongated cross-shaped organic scaffold was successfully incorporated into a highly porous, non-interpenetrated square-grid copper(II)-organic framework material with the unprecedentedly huge dimensions of 25.5 x 25.5 angstrom(2), while the layer-to-layer NH center dot center dot center dot N interaction leads to a unique hydrogen-bonded 6(4).8(2)-nbo net.
Enhanced light-harvesting capability by phenothiazine in ruthenium sensitizers with superior photovoltaic performance
(2012)
Yin, Jen-Fu
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Chen, Jian-Ging
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Lin, Jiann-T'suen
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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.
Enhanced photovoltaic performance by synergism of light-cultivation and electronic localization for highly efficient dye-sensitized solar cells
(2009)
Yin, Jen-Fu
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Bhattacharya, Dibyendu
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Hsu, Ying-Chan
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Tsai, Chen-Chuan
;
Lu, Kuang-Lieh
Two ruthenium sensitizers, [Ru(dcbpy)(opip)(NCS)(2)] (JF-1, dcbpy 4,4'-dicarboxylic acid-2,2'-bipyridine, opip = 2-(4-octylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ru(dcbpy)(otip)(NCS)(2)] (JF-2, otip = 2-(5-octylthiophen-2-yl)-1H-imidazo[4,5-f][1,10]phenanthroline), with unusually high power-conversion efficiency in comparison with other ruthenium complexes containing 1,10-phenanthroline-based ligands were designed. The power-conversion efficiency of JF-2 is 20% higher than that of JF-1, due to the modification of the ancillary ligand with a thiophene moiety. The origins of this device performance diversity are illustrated by photophysical properties, electrochemical data and density functional theory (DFT) studies. The greater device performance of JF-2 compared to JF-1 was caused from the broader MLCT distribution, the appropriate localization of the frontier orbitals and the stronger driving force of the charge injection and regeneration.
Highly hydrophobic metal-organic framework for self-protecting gate dielectrics
(2020-06-28)
Inamdar, Arif I.
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Pathak, Abhishek
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Usman, Muhammad
;
Chiou, Kuan-Ru
;
Tsai, Pei-Hsien
A hydrophobic metal-organic framework (MOF) showing high-kappa behaviour was synthesized by the reaction of copper ions with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (HFDPA). The unique, highly hydrophobic nature of the material protects it from re-adsorbing water, even in a high humidity environment. The dielectric constant of the MOF showed an unprecedented increasing trend, reaching up to kappa approximate to 99 at 300 K and 1 kHz after the complete removal of guest and coordinated water molecules. The unusual dielectric behaviour of the compound along with its water resistant properties is the first report of such behaviour and it paves the way for the development of moisture-stable microelectronic devices.
Hydrothermally Roughened Surface-Enhanced Raman Scattering-Active Substrates with Low Background Signals for Chemical Sensing Application
(2011-03-01)
Yang, Jung-Yen
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Cheng, Hui-Wen
;
Chen, Yu
;
Li, Yiming
;
Lin, Chi-Hung
A low-cost, environment friendly and easily fabricated SERS-active substrate with low background signals has been developed by hydrothermal treatment of titanium thin films deposited on silicon substrate. Results from the experimental study revealed that Rhodamine 6G can be well resolved using gold-coated hydrothermally roughened TiO(2) substrates. The effect of surface enhancement by the hydrothermally roughened substrates enables rapid identification of Rhodamine 6G, and the enhancement capability is controllable by tuning the surface roughness of the substrates through varying treatment duration. The hydrothermally treated TiO(2) substrates also exhibit tunable wettability like that of the untreated ones.
Intrinsic Ultralow-Threshold Laser Action from Rationally Molecular Design of Metal-Organic Framework Materials
(2020-08-12)
Bera, Krishna Prasad
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Kamal, Saqib
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Inamdar, Arif I.
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Sainbileg, Batjargal
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Lin, Hung-, I
Metal-organic frameworks (MOFs) are superior for multiple applications including drug delivery, sensing, and gas storage because of their tunable physiochemical properties and fascinating architectures. Optoelectronic application of MOFs is difficult because of their porous geometry and conductivity issues. Recently, a few optoelectronic devices have been fabricated by a suitable design of integrating MOFs with other materials. However, demonstration of laser action arising from MOFs as intrinsic gain media still remains challenging, even though some studies endeavor on encapsulating luminescence organic laser dyes into the porous skeleton of MOFs to achieve laser action. Unfortunately, the aggregation of such unstable laser dyes causes photoluminescence quenching and energy loss, which limits their practical application. In this research, unprecedently, we demonstrated ultralow-threshold (similar to 13 nJ/cm(2)) MOF laser action by a judicious choice of metal nodes and organic linkers during synthesis of MOFs. Importantly, we also demonstrated that the white random lasing from the beautiful microflowers of organic linkers possesses a porous network, which is utilized to synthesize the MOFs. The highly luminescent broad-band organic linker 1,4-NDC, which itself exhibits a strong white random laser, is used not only to achieve the stimulated emission in MOFs but also to reduce the lasing threshold. Such white lasing has multiple applications from bioimaging to the recently developed versatile Li-Fi technology. In addition, we showed that the smooth facets of MOF microcrystals can show Fabry-Perot resonant cavities having a high quality factor of similar to 10(3) with excellent photostability. Our unique discovery of stable, nontoxic, high-performance MOF laser action will open up a new route for the development of new optoelectronic devices.
Structural planarity and conjugation effects of novel symmetrical acceptor-donor-acceptor organic sensitizers on dye-sensitized solar cells
(2012-04-01)
Chu, Hsuan-Chih
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Sahu, Duryodhan
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Hsu, Ying-Chan
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Padhy, Harihara
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Patra, Dhananjaya
In this study two series of novel symmetrical acceptor-donor-acceptor organic sensitizers containing 3,6- and 2,7-functionalized carbazole cores, respectively, connected to two anchoring cyanoacrylic acid termini via thienyl linkers were synthesized. The effect of the molecular planarity originating from the 3,6- and 2,7-functionalized carbazole cores on the performance of corresponding solar cells were investigated. Molecular orbital analyses revealed the characteristics of the carbazole-based highest occupied molecular orbitals and acid-based lowest unoccupied molecular orbitals. Time-dependent density functional theory calculations allowed us to assign the electronic transitions (>90%) of the low energy bands. Among these new dyes, the highest power conversion efficiency of 4.82% was obtained in a dye-sensitized solar cell device under standard AM 1.5 sunlight with an open-circuit voltage of 0.61 V, a short-circuit photocurrent density of 12.66 mA cm(-2) and a fill factor of 0.62. (C) 2011 Elsevier Ltd. All rights reserved.
Structure optimization of ruthenium photosensitizers for efficient dye-sensitized solar cells - A goal toward a "bright" future
(2012-12-01)
Yin, Jen-Fu
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Velayudham, Murugesan
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Bhattacharya, Dibyendu
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Lin, Hong-Cheu
;
Lu, Kuang-Lieh
Research on dye-sensitized solar cells (DSC) is progressing at a rapid pace. The structural and electronic factors associated with ruthenium photosensitizers can have a significant effect on the performance of DSCs. This review emphasizes the recent developments and strategies employed in the structural design of ruthenium photosensitizers. The influence of molecular engineering on photophysical and electrochemical properties along with photovoltaic parameters and the efficiency of DSCs are also reviewed. Hence, drawing a correlation between the structure of photosensitizers, the properties and photovoltaic parameters of corresponding DSCs will be helpful in terms of optimizing new dyes for the generation of efficient solar cells. (c) 2012 Elsevier B.V. All rights reserved.
Synthesis and applications of novel acceptor-donor-acceptor organic dyes with dithienopyrrole- and fluorene-cores for dye-sensitized solar cells
(2011-01-14)
Sahu, Duryodhan
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Padhy, Harihara
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Patra, Dhananjaya
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Yin, Jen-Fu
;
Hsu, Ying-Chan
Four novel symmetrical organic dyes (S1-S4) configured with acceptor-donor-acceptor (A-D-A) structures containing electron donating fluorene (S1 and S2) and N-alkyl dithieno[3,2-b:2',3'-d]pyrrole (DTP) (S3 and S4) cores terminated with two anchoring cyanoacrylic acids (as electron acceptors) were synthesized and applied to dye-sensitized solar cells (DSSCs). The DSSC device based on S2 dye showed the best photovoltaic performance among S1-S4 dyes: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 76%, a short circuit current (J(SC)) of 12.27 mA/cm(2), an open circuit voltage (V(OC)) of 0.61 V. a fill factor (FF) of 0.63, and an overall power conversion efficiency (eta) of 4.73%. Besides, the utilization of chenodoxycholic acid (CDCA) as a co-adsorbent in the DSSC device based on S3 dye showed a significant improvement in its eta value (from 3.70% to 4.31%), which is attributed to the suppression of dye aggregation on TiO(2) surface and thus to increase the J(SC) value eventually. (C) 2010 Elsevier Ltd. All rights reserved.
Toward Optimization of Oligothiophene Antennas: New Ruthenium Sensitizers with Excellent Performance for Dye-Sensitized Solar Cells
(2010-08-10)
Yin, Jen-Fu
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Chen, Jian-Ging
;
Lu, Zong-Zhan
;
Ho, Kuo-Chuan
;
Lin, Hong-Cheu
This paper reports on the design and synthesis of three new ruthenium sensitizers, as well as the optimization of their linear or dendritic light-harvesting oligothiophene antennas to achieve superior device performance. The three new ruthenium sensitizers, [Ru(dcbpy)(obtip)(NCS)(2)] (JF-5, dcbpy = 4,4'-dicarboxylic obtip = 2-(5-octyl-(2,2'-bithiophen)-5'-yl)-1H-imidazo[4,51][1,10]-phenanthroline), [Ru(dcbpy)(ottip)(NCS)(2)] (JF-6, ottip = 2-(5-octyl-2,2',5',2 ''-terthiophen)-5 ''-yl)-1H-imidazo[4,5-f][1,10]-phenanthroline), and [Ru(dcbpy)(dottip)(NCS)(2)] (JF-7, dottip = di-(5-octylthiophen-2-ypthiophen-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline), were synthesized in a typical one-pot reaction. The ruthenium sensitizer JF-5 incorporating a linear and planar 2,2'-bithiophene antenna showed the best DSCs performance (9.5%; compared to N3, 8.8%). The difference in the performance of these sensitizers demonstrates that elongating the linear and planar light-harvesting antenna result in an enhancement in MLCT intensity, but a reduction in the quantity of dye-loading. This finding not only permitted the power-conversion efficiency in ruthenium sensitizers containing oligothiophene antennas to be optimized, but also points to a promising direction for molecule engineering in DSCs.
Zr-MOF/Polyaniline Composite Films with Exceptional Seebeck Coefficient for Thermoelectric Material Applications
(2019-01-23)
Lin, Chih-Chien
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Huang, Yi-Chia
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Usman, Muhammad
;
Chao, Wen-Hsuan
;
Lin, Wei-Keng
Controlling the polymerization of aniline in the presence of zirconium-based metal-organic frameworks (Zr-MOFs) using polystyrene sulfonic acid as a dopant resulted in the formation of a new type of freestanding thermoelectric composite film. Polyaniline chains interpenetrate into the Zr-MOFs to enhance the crystallinity of polyaniline, resulting in an improved degree of electrical conductivity. In addition, the inherent porosity of the Zr-MOFs functions to suppress the increase in thermal conductivity, thus dramatically promoting a negative Seebeck coefficient. When 20 wt % Zr-MOF was used, a power factor of up to 664 mu W/(m K-2) was obtained, which was accompanied by a surprisingly large, negative Seebeck coefficient. The new class of MOF-based composites offers a new direction for developing new types of efficient thermoelectric materials.