Quenching of Water Soluble Conjugated Polymer by Electrostatic Interaction

Jin, Youngeup Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.11

The water-soluble conjugated polymer with fluorescence quenching as a result of electrostatic interaction and aggregation was synthesized through Suzuki polymerization. The absorption and emission of anionic polymer (a-PFP) is blue shifted as compared with cationic polymer (c-PFP) although getting same backbone, and the absolute PL quantum efficiency of a-PFP in water is over 90% due to good solubility in aqueous solution. We anticipate that the fluorescence quenching of anionic and cationic polymers, with same conjugated backbone, could be shown in aqueous solution.

Synthesis of novel conjugated polymer based on cyclopenta[def]phenanthrene and vinylene with strong interchain interaction

Jin, Youngeup,Lee, Minjung,Kim, Sun Hee,Song, Suhee,Kim, Il,Woo, Han Young,Lee, Kwanghee,Suh, Hongsuk Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science Part A, Polymer chemist Vol.47 No.19

<P>In this study, a novel conjugated polymer, poly(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene-2,6-vinylene) (PCPPV) has been synthesized and characterized. For the polymerization, Gilch's reaction was applied for the first time with the cyclopenta[def]phenanthrene system. The absorption and emission spectra of PCPPV are red-shifted about 40–50 nm due to the vinylene units when compared with those of poly(2,6-(4,4-bis(2-ethylhex-yl)-4H-cyclopenta[def]phenanthrene)) (PCPP). The solid-state fluorescence is significantly broadened, possibly due to π–π interactions introduced by the phenanthrene and vinylene moieties. In solution, as the concentration of polar solvent increased, the photoluminescence (PL) intensity decreased due to quenching and aggregation by the interchain interactions between the conjugated backbones. After annealing the film at 80 °C, the PL and electroluminescence (EL) emission spectra exhibited also the quenching and aggregation effects indicating the interchain interactions of PCPPV. The large number of aromatic rings in a unit and the increased planarity achieved through introduction of vinylene units are able to give interchain interactions stronger than fluorene or phenylene units. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5068–5077, 2009</P> <B>Graphic Abstract</B> <P>In this work, a novel conjugated polymer, poly(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene-2,6-vinylene) (PCPPV), has been synthesized by Gilch's reaction. The absorption and emission spectra of PCPPV are red-shifted about 40–50 nm due to the vinylene units when compared with those of PCPP. The solid-state fluorescence is significantly broadened, possibly due to π–π interactions introduced by the phenanthrene and vinylene moieties. After annealing the film at 80 °C, the PL and EL emission spectra exhibited also the quenching and aggregation effects indicating the interchain interactions of PCPPV. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] <img src='wiley_img/0887624X-2009-47-19-POLA23559-gra001.gif' alt='wiley_img/0887624X-2009-47-19-POLA23559-gra001'> </P>

Synthesis and characterization of polyfluorenevinylene with cyano group and carbazole unit

Song, Suhee,Jin, Youngeup,Kim, Sun Hee,Shim, Joo Young,Son, Sooyeon,Kim, Il,Lee, Kwanghee,Suh, Hongsuk Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science Part A, Polymer chemist Vol.47 No.23

<P>The present investigation deals with the synthesis, characterization, and EL properties of new polyfluorenevinylenes, CzCNPFVs, with cyano-substituted vinylene unit and carbazole pendant. In CzCNPFVs, synthesized by the Knoevenagel condensation, the carbazole pendant was introduced to improve the efficiency of reported CNPFV. The PL emission spectra of the CzCNPFVs in chloroform solution show maximum peaks at 476–479 nm. In thin films, maximum peaks of the CzCNPFVs appeared at 501–504 nm, red-shifted around 25 nm as compared to those in solution. The emission maxima of the EL spectra of the polymers appear at around 496–504 nm. The maximum luminescence (L<SUB>max</SUB>) of CzCNPFV2 of the device with the configuration of ITO/PEDOT/CzCNPFVs/Ca/Al is 1724 cd/m<SUP>2</SUP> at 8 V. The maximum luminescence efficiency of CzCNPFV1 is 0.18 cd/A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6540–6551, 2009</P> <B>Graphic Abstract</B> <P>The present investigation deals with the synthesis, characterization, and EL properties of new polyfluorenevinylenes, CzCNPFVs, with cyano-substituted vinylene unit and carbazole pendant. In CzCNPFVs, the carbazole pendant was introduced to improve the efficiency of reported CNPFV. The maximum luminescence (L<SUB>max</SUB>) of CzCNPFV2 of the device with the configuration of ITO/PEDOT/CzCNPFVs/Ca/Al is 1724 cd/m<SUP>2</SUP> at 8 V. The maximum luminescence efficiency of CzCNPFV1 is 0.18 cd/A. <img src='wiley_img/0887624X-2009-47-23-POLA23697-gra001.gif' alt='wiley_img/0887624X-2009-47-23-POLA23697-gra001'> </P>

A low-bandgap alternating copolymer containing the dimethylbenzimidazole moiety

Song, Suhee,Jin, Youngeup,Park, Sung Heum,Cho, Shinuk,Kim, Il,Lee, Kwanghee,Heeger, Alan J.,Suh, Hongsuk Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.31

<P>A new acceptor unit containing dimethyl-2<I>H</I>-benzimidazole was synthesized and utilized for the synthesis of a conjugated polymer containing electron donor–acceptor pairs for OPV devices. The dimethyl-2<I>H</I>-benzimidazole unit was designed to act as a substitute for the BT unit of <B>PCDTBT</B>. This novel dimethyl-2<I>H</I>-benzimidazole unit has two methyl groups which can supply higher solubility than those of the BT series. A thin film of <B>PCDTMBI</B>, containing the dimethyl-2<I>H</I>-benzimidazole unit, shows two broad absorption bands with maxima at 400 and 636 nm and an absorption onset of 756 nm, corresponding to a band gap of 1.64 eV. The oxidation onset of <B>PCDTMBI</B> was estimated to be 0.67 V, which corresponds to a HOMO energy level of −5.47 eV. The LUMO energy level of the polymer was thus determined to be −3.82 eV. A device with a <B>PCDTMBI</B>:PC<SUB>71</SUB>BM blend had a <I>V</I><SUB>OC</SUB> value of 0.65 V, a <I>J</I><SUB>SC</SUB> value of 10.0 mA cm<SUP>−2</SUP>, and a <I>FF</I> of 0.48, leading to an efficiency of 3.12%. The enhanced efficiency of <B>PCDTMBI</B> was caused by the higher IPCE value between 400 and 700 nm and high mobility (2.2 × 10<SUP>−3</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>).</P> <P>Graphic Abstract</P><P>A new acceptor unit containing dimethyl-2<I>H</I>-benzimidazole was synthesized and utilized for the synthesis of a conjugated polymer containing electron donor–acceptor pairs for OPV devices. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm00772b'> </P>

PCPP derivatives containing carbazole pendant as hole transporting moiety for efficient blue electroluminescence

Kim, Jinwoo,Jin, Youngeup,Kim, Jaehong,Jung, Jaeyeon,Kim, Sun Hee,Lee, Kwanghee,Suh, Hongsuk Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science Part A, Polymer chemist Vol.47 No.5

<P>The syntheses and characterization of poly((2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene))-co-(2,6-(4,4-bis(4-(((9-carbazolyl)hexyl)oxy)phenyl))-4H-cyclopenta[def]phenanthrene)) (BCzPh-PCPPs) and poly((2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene))-co-(2,6-(4-(4-(((9-carbazolyl)hexyl)oxy)phenyl)-4-(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene))) (CzPh-PCPPs), with carbazole unit as pendants, are presented. The carbazole moiety, which can improve the hole injection ability, was introduced as a pendant on the PCPP backbone. The devices of the polymers with the configurations of ITO/PEDOT:PSS/polymers/Ca/Al generate EL emission with maximum peaks at 400–450 nm, CIE coordinates of (x = 0.11–0.29, y = 0.11–0.33), low turn-on voltages of 4–6 V, maximum brightness of 60–810 cd/m<SUP>2</SUP>, and luminescence efficiencies of 0.04–0.22 cd/A. The PL spectra of CzPh-PCPPs films did not show any peak at around 550 nm, which corresponds to keto defect or aggregate/excimer formation, even after annealing for 30 h at 150 °C in air. Out of the series, CzPh-PCPP1 (PCPP derivative with 10% of carbazole moiety as pendant) shows blue emission with the maximum brightness of 810 cd/m<SUP>2</SUP> at 9 V, and the highest luminescence efficiency of 0.22 cd/A at 395 mA/cm<SUP>2</SUP>. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1327–1342, 2009</P> <B>Graphic Abstract</B> <P>The conjugated copolymers of BCzPh-PCPPs and CzPh-PCPPs with carbazole pendant were synthesized by Suzuki reaction. The carbazole moiety, which can improve the hole injection ability, was introduced as a pendant on the PCPP backbone. Their thermal, electrochemical, photoluminescent, and electroluminescent properties were investigated. <img src='wiley_img/0887624X-2009-47-5-POLA23241-gra001.gif' alt='wiley_img/0887624X-2009-47-5-POLA23241-gra001'> </P>

Synthesis and Characterization of Novel Conjugated Polymer with 4H-Cyclopenta[def]phenanthrene and the Sulfanyl Group

Song, Suhee,Jin, Youngeup,Kim, Sun Hee,Kim, Joo Hyun,Lee, Kwanghee,Suh, Hongsuk Springer Science and Business Media LLC 2009 Polymer journal Vol.41 No.2

Synthesis of 4<i>H</i>-Cyclopenta[<i>def</i>]phenanthrene from 1-Naphthylacetic Acid

Kim, Jinwoo,Jin, Youngeup,Song, Suhee,Kim, Il,Suh, Hongsuk The Chemical Society of Japan 2009 Chemistry letters Vol.38 No.10

<P>4<I>H</I>-cyclopenta[<I>def</I>]phenanthrene (CPP) was prepared from 1-naphthylacetic acid in six steps with an overall yield of 36%. From easily available ethyl 1-naphthaleneacetate, the Michael addition and Lewis acid catalyzed dicyclization provided the diketone, which was reduced and dehydrated to give CPP.</P>

Organic Electroluminescent Devices Based on Polyurethane Derivatives Having Substituted Stilbene Pendants

Lee, Gyu Hyun,Jin, Youngeup,Lee, Sungeun,Lee, Jong Gun,Kim, Jin Young,Lee, Kwanghee,Jin, Sung-Ho,Ha, Chang-Sik,Won, Mi-Sook,Kang, Shin-Won,Suh, Hongsuk 부산대학교 유전공학연구소 2002 분자생물학 연구보 Vol.18 No.-

There have been extensive research efforts on organic electroluminescent devices (OELDs) with the aim of application for the flat panel display (FPD). OELDs have also attracted much interest because of their particular low driving voltage, convenient design of the device structures, possible control of emission band, and low fabrication cost compared with any other devices. OELDs can be classified as either molecular or polymer-based. Molecular-based devices consist of vacuum deposited fluorescent emitter layers whereas polymer-based devices consist of either spinor dip-coated layers. Most of the research in the field of polymer-chain conducting polymers such as poly(plenylene vinylene) (PPV), poly(p-phenylene) (PPP), their copolymers and soluble derivatives. Other groups have reported non-conjugated polymers with pendant chromophores for OELDs. The attachment of the fluorophore as the pendant group of a random-coil polymer presents several advantages: (1) the synthetic route would be simpler than that used for main-chain polymers; (2) the moderate solubility could be obtained by the nature of the backbone; (3) the emission wavelength would be easily controllable. We, recently, reported the PU polymer with the 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) dye as the pendant. Even though it is known that the PU backbone have many quenching sites, the turn-on voltage of the PU-DCM device was ca. 5 V. Also, the change of the fluorophores in the side chain from para-cyanostilbene(PU-CN) to DCN (PU-DCM) caused the shift of PL emission wavelength. For the PL emission spectra of PU-CN and PU-DCM, the maximum peaks were at ca. 520 and 630 nm, respectively, corresponding to the maximum PL peaks. Therefore, EL, and PL properties can be changed using different lumophore pendant groups possibly caused by the electron withdrawing effect of the DCM prndant. In the present work, PU derivatives with stilbene pendant. In the present work, PU derivatives with stilbene pendant containing one or two fluoro group were introduced on the stilbene side chain. OELDs using polyurethane derivatives with stilbene pendants were fabricated to investigate the effect of the electron withdrawing substituents of the lumophore pendant on the EL and PL properties. Since PU derivatives possess different electron withdrawing substituents on the stilbence pendant, the shift of emission wave-length is expected.

기공형 polyethersulfone/TiO₂ 복합체 멤브레인의 유기염료분해 반응에 대한 광촉매 특성 연구

송창현 ( Chang Hyeon Song ),진영읍 ( Youngeup Jin ),이원기 ( Won Ki Lee ),유성일 ( Seong Il Yoo ) 한국공업화학회 2023 공업화학 Vol.34 No.1

광촉매 기반의 수처리 공정에서 TiO₂ 나노입자와 기공형 고분자로 구성된 복합체 멤브레인은 광촉매 반응후 나노입자를 회수하기 용이하다는 장점과 멤브레인 파울링(fouling) 억제가 가능하다는 측면에서 다양하게 연구되어 왔다. 하지만, TiO₂ 나노입자가 복합체 멤브레인에 고착된 이후 나노입자의 광촉매 특성이 어떻게 변할지에 대한 연구는 상대적으로 많이 진행되지 않았다. 이러한 측면에서, 본 연구에서는 polyethersulfone (PES)/TiO₂ 복합체 멤브레인을 제조하고 유기염료분해 반응에 대한 광촉매 특성을 연구하였다. 복합체 멤브레인에 고착된 TiO₂ 나노입자의 염료분해반응 속도를 콜로이드 상에서 분산된 TiO₂ 나노입자와 비교함으로써 멤브레인에 고착화되기 전후의 TiO₂ 나노입자의 촉매 효율을 비교하였다. Composite membranes consisting of TiO₂ nanoparticles (NPs) and porous polymers have been widely utilized in photocatalytic water treatment because the composite membranes can allow an easy recovery of NPs after the photocatalytic reaction as well as the reduction of fouling in the membrane. However, the photocatalytic efficiency of the immobilized TiO₂ NPs in the composite membranes has been discussed to a limited degree. In this study, we prepared polyethersulfone (PES)/TiO₂ composite membranes to study the photocatalytic decomposition of organic dyes under light illumination. The decomposition kinetics of dye molecules by the PES/TiO₂ composite membranes and colloidal TiO₂ NPs have been compared to discuss the photocatalytic efficiency of NPs before and after their immobilization on the polymer membrane.

가시광선하에서 Cd0.5Zn0.5S/ZnO 광촉매를 이용한 로다민 B의 광분해 반응

이현정 ( Hyun Jung Lee ),진영읍 ( Youngeup Jin ),박성수 ( Seong Soo Park ),홍성수 ( Seong Soo Hong ),이근대 ( Gun Dae Lee ) 한국공업화학회 2015 공업화학 Vol.26 No.3

Cd0.5Zn0.5S/ZnO composite photocatalysts were synthesized using the precipitation method and characterized by XRD, UV-vis DRS, PL and FE-SEM. Photocatalytic activities of the materials were evaluated by measuring the degradation of rhodamine B under visible light irradiation. Contrary to ZnO, Cd0.5Zn0.5S/ZnO materials absorb visible light as well as UV and their absorption intensities in visible region increased with increasing the Cd0.5Zn0.5S amount. The increment in the Cd0.5Zn0.5S content in Cd0.5Zn0.5S/ZnO also leads to reducing the particle size and consequently increasing the specific surface area. Cd0.5Zn0.5S/ZnO materials with the larger Cd0.5Zn0.5S content showed the higher activity in the photocatalytic degradation of rhodamine B under visible light irradiation. Therefore, the heterojunction effect between Cd0.5Zn0.5S and ZnO as well as the adsorption capacity seems to give important contributions to the photocatalytic activity of the Cd0.5Zn0.5S/ZnO.