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Kranthiraja K.,Institute for Plastic Information and Energy Materials | Gunasekar K.,Institute for Plastic Information and Energy Materials | Song M.,Korea Institute of Materials Science | Gal Y.-S.,Kyungil University | And 2 more authors.
Bulletin of the Korean Chemical Society | Year: 2014

We have designed and developed a new ladder type tetrafused π-conjugated building block such as dihydroindolo[3,2-b]indole (DINI) and investigated its role as an electron rich unit. The photovoltaic properties of a new semiconducting π-conjugated polymer, poly[[5,10-bisoctyl-5,10- dihydroindolo[3,2-b]indole-[5,6- bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1, 2,5]thiadiazole]], represented by PDINI-OBTC8 are described. The new polymer PDINI-OBTC8 was synthesized in donor-acceptor (D-A) fashion, where fused π-conjugated tetracyclic DINI, and 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl) benzo[c][1,2,5]thiadiazole (OBTC8) were employed as electron rich (donor) and electron deficient (acceptor) moieties, respectively. The conventional bulk heterojunction (BHJ) device structure ITO/PEDOT:PSS/PDINI-OBTC8:PCB 71M/LiF/Al was utilized to fabricate polymer solar cells (PSCs), which comprises the blend of PDINI-OBTC8 and [6,6]-phenyl-C71- butyric acid methyl ester (PC71BM) in BHJ network. A BHJ PSC that contain PDINI-OBTC8 delivered power conversion efficiency (PCE) value of 1.68% with 1 vol% of 1,8-diidooctane (DIO) under the illumination of A.M 1.5G 100 mW/cm2. Source


Park J.S.,Institute for Plastic Information and Energy Materials | Jin S.-H.,Institute for Plastic Information and Energy Materials | Gal Y.-S.,Kyungil University | Lee J.H.,Dong - A University | Lee J.W.,Dong - A University
Molecular Crystals and Liquid Crystals | Year: 2012

A new thermally robust electroluminescent (EL) carbazole-based-conjugated copolymer, including poly[3,7-(N-hexylcarbazole)-co-4,7-{5,6-bis(3,7- dimethyloctylo-xymethyl)-2,1,3-(benzothiadiazole)}] (PCz-co-P2C 10BT) was synthesized and used to fabricate the efficient polymer light-emitting diodes (PLEDs). The glass transition temperature of the PCz-co-P2C 10BT (105C) was found to be higher than that of poly(9,9- dialkylfluorene) derivatives. We fabricated PLEDs in ITO/PEDOT/light-emitting polymer/Alq 3/LiF/Al configuration. The new copolymer was found to have green emission color (523nm). The maximum brightness and external quantum efficiency of PCz-co-P2C 10BT were 260 cd/m 2 at 14V and 0.22%, respectively. © 2012 Taylor & Francis Group, LLC. Source


Ahn S.K.,Institute for Plastic Information and Energy Materials | Song M.,Institute for Plastic Information and Energy Materials | Gal Y.-S.,Kyungil University | Lee J.W.,Dong - A University | Jin S.-H.,Institute for Plastic Information and Energy Materials
Molecular Crystals and Liquid Crystals | Year: 2012

To investigate electroluminescent (EL) properties of a novel-conjugated polymer, poly[N-(3,4-bis(decyloxy)phenyl)carbazolyl-2,7-vinylene)] (PCzV) was synthesized. The polymer is soluble in common organic solvents such as chloroform and chlorobenzene and could be easily spin-coated onto an indium-tin oxide coated glass substrate to obtain high quality optical thin films. The polymer has a weight-average molecular weight (M w) of ca. 3.86 10 4 with a polydispersity of 1.60. The polymer light-emitting diodes (PLEDs) with a configuration of ITO/PEDOT:PSS/polymer/OXD-7/LiF/Al were fabricated. The maximum luminance and luminance efficiency showed 1207 cd/m 2 and 1.11 cd/A with CIE coordinate of (0.15, 0.27), respectively. © 2012 Taylor & Francis Group, LLC. Source


Rhee S.H.,Sun Moon University | Nam K.B.,Sun Moon University | Kim C.S.,Korea Institute of Materials Science | Song M.,Korea Institute of Materials Science | And 3 more authors.
ECS Solid State Letters | Year: 2014

The charge balance mechanism in green fluorescent organic light-emitting diodes is investigated for different electron transport layers (ETLs) and electron mobilities. Carrier accumulation and an increase in the exciton recombination probability are shown to be critical for improving the current and power efficiencies by aligning the bands at the interface between the emitting layer (EML) and ETL. The peak in the electroluminescence (EL) spectra was found to shift slightly in response to changes in the width of the emission zone and reflected the electron mobility of the ETL. Higher electron mobility resulted in a wider recombination zone in the EML that was manifested by a blue-shift of the EL peak. © 2014 The Electrochemical Society. Source


Kim .K.T.,Institute for Plastic Information and Energy Materials | Jin S.-H.,Institute for Plastic Information and Energy Materials | Chang S.-C.,Pusan National University | Park D.-S.,Pusan National University
Bulletin of the Korean Chemical Society | Year: 2013

A new synthesis route for Pt nanoparticles by direct electrochemical reduction of a solid-state Pt ion precursor (K2PtCl6) is demonstrated. Solid K2PtCl6-supported polyethyleneimine (PEI) coatings on the surface of glassy carbon electrode were prepared by simple mixing of solid K2PtCl6 into a 1.0% PEI solution. The potential cycling or a constant potential in a PBS (pH 7.4) medium were applied to reduce the solid K2PtCl6 precursor. The reduction of Pt(IV) began at around -0.2 V and the reduction potential was ca. -0.4 V. A steady state current was achieved after 10 potential cycling scans, indicating that continuous formation of Pt nanoparticles by electrochemical reduction occurred for up to 10 cycles. After applying the reduction potential of -0.6 V for 300 s, Pt nanoparticles with diameters ranging from 0.02-0.5 μm were observed, with an even distribution over the entire glassy carbon electrode surface. Characteristics of the Pt nanoparticles, including their performance in electrochemical reduction of H2O2 are examined. A distinct reduction peak observed at about -0.20 V was due to the electrocatalytic reduction of H2O2 by Pt nanoparticles. From the calibration plot, the linear range for H2O2 detection was 0.1-2.0 mM and the detection limit for H2O2 was found to be 0.05 mM. Source

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