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RISS 인기검색어
- 검색키워드
- 저자 : Jea Woong Jo (검색결과 27 건)
- 무료
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Jo, Jea Woong,Jung, Jae Woong,Lee, Jea Uk,Jo, Won Ho American Chemical Society 2010 ACS NANO Vol.4 No.9
<P>Oligothiophene-terminated poly(ethylene glycol) was synthesized and used as a non-ionic and amphiphilic surfactant for fabricating high-quality single-walled carbon nanotube (SWCNT) films by a simple spin coating method. The absence of charge repulsion between SWCNT/surfactant complexes successfully leads to formation of a dense network of SWCNTs on the substrate through a single deposition of spin coating. When the SWCNT film was treated with nitric acid and thionyl chloride after washed with dichloromethane and water, a high-performance SWCNT film with the sheet resistance of 59 ohm/sq and the transparency of 71% at 550 nm was successfully obtained. Since the SWCNT film exhibits a high value of σ<SUB>dc</SUB>/σ<SUB>ac</SUB> (∼17) and excellent dimensional stability after releasing from the substrate, the film can be used as a transparent electrode in flexible optoelectronic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-9/nn1009837/production/images/medium/nn-2010-009837_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn1009837'>ACS Electronic Supporting Info</A></P>
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Jo, Jea Woong,Jung, Jae Woong,Jung, Eui Hyuk,Ahn, Hyungju,Shin, Tae Joo,Jo, Won Ho The Royal Society of Chemistry 2015 ENERGY AND ENVIRONMENTAL SCIENCE Vol.8 No.8
<P>Fluorination of conjugated polymers is one of the effective strategies to tune the frontier energy levels for achieving high efficiency polymer solar cells. In this study, three fluorinated D-A polymers, consisting of 3,3'-difluoro-2,2'-bithiophene and 2,1,3-benzothiadiazole (BT) with different numbers of fluorine substitution, were synthesized in order to investigate the effect of fluorination on their photovoltaic properties. The polymers with fluorinated BT show lower frontier energy levels, improved polymer ordering, and a narrower fibril size in the blend with PC71BM. The polymer with mono-fluorinated BT exhibits a superior PCE of 9.14% due to a high SCLC hole mobility, mixed orientation of polymer crystals in the active layer, and low bimolecular recombination. This result demonstrates that the fluorine content in conjugated polymers should be controlled for optimizing optoelectrical and photovoltaic properties of fluorinated conjugated polymers.</P>
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Acid-Assisted Ligand Exchange Enhances Coupling in Colloidal Quantum Dot Solids
Jo, Jea Woong,Choi, Jongmin,Garcí,a de Arquer, F. Pelayo,Seifitokaldani, Ali,Sun, Bin,Kim, Younghoon,Ahn, Hyungju,Fan, James,Quintero-Bermudez, Rafael,Kim, Junghwan,Choi, Min-Jae,Baek, Se-Woong American Chemical Society 2018 NANO LETTERS Vol.18 No.7
<P>Colloidal quantum dots (CQDs) are promising solution-processed infrared-absorbing materials for optoelectronics. In these applications, it is crucial to replace the electrically insulating ligands used in synthesis to form strongly coupled quantum dot solids. Recently, solution-phase ligand-exchange strategies have been reported that minimize the density of defects and the polydispersity of CQDs; however, we find herein that the new ligands exhibit insufficient chemical reactivity to remove original oleic acid ligands completely. This leads to low CQD packing and correspondingly low electronic performance. Here we report an acid-assisted solution-phase ligand-exchange strategy that, by enabling efficient removal of the original ligands, enables the synthesis of densified CQD arrays. Our use of hydroiodic acid simultaneously facilitates high CQD packing via proton donation and CQD passivation through iodine. We demonstrate highly packed CQD films with a 2.5 times increased carrier mobility compared with prior exchanges. The resulting devices achieve the highest infrared photon-to-electron conversion efficiencies (>50%) reported in the spectral range of 0.8 to 1.1 eV.</P> [FIG OMISSION]</BR>
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Woong Jung, Jae,Woong Jo, Jea,Liu, Feng,Russell, Thomas P.,Ho Jo, Won The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.55
<P>A low band-gap conjugated polymer, PBDTDPP, composed of unsubstituted benzo[1,2-<I>b</I>:4,5-<I>b</I>′]dithiophene and diketopyrrolo[3,4-<I>c</I>]pyrrole was synthesized. The deep HOMO level of PBDTDPP enhances the <I>V</I><SUB>OC</SUB> of a PSC up to 0.82 V and exhibits a PCE of 5.16%, while alkoxy substituted PBDTDPP-OR yields a PCE of 2.24% with a <I>V</I><SUB>OC</SUB> of 0.61 V.</P> <P>Graphic Abstract</P><P>A low band-gap conjugated polymer, PBDTDPP, composed of unsubstituted benzo[1,2-<I>b</I>:4,5-<I>b</I>′]dithiophene and diketopyrrolo[3,4-<I>c</I>]pyrrole was synthesized; <I>V</I><SUB>OC</SUB> of a PSC up to 0.82 V and PCE of 5.16% were obtained. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc32985a'> </P>
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Fluorination of Polythiophene Derivatives for High Performance Organic Photovoltaics
Jo, Jea Woong,Jung, Jae Woong,Wang, Hsin-Wei,Kim, Paul,Russell, Thomas P.,Jo, Won Ho American Chemical Society 2014 Chemistry of materials Vol.26 No.14
<P>For the purpose of examining the tuning of photophysical property by fluorine atom substitution, fluorinated and nonfluorinated poly(3,4-dialkylterthiophenes) (PDATs) were synthesized, and their photovoltaic properties were compared. Fluorinated PDATs exhibit a deeper highest occupied molecular orbital energy level than nonfluorinated ones, leading to higher open-circuit voltage in organic solar cells and also enhanced molecular ordering as evidenced by a vibronic shoulder in UV–vis spectra, π–π scattering in GIWAXS, and a well-developed fibril structure in TEM, which contributes to efficient charge transport. As a result, the fluorine substitution increases the power conversion efficiency by 20% to 250% as compared with nonfluorinated PDATs.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2014/cmatex.2014.26.issue-14/cm502229k/production/images/medium/cm-2014-02229k_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm502229k'>ACS Electronic Supporting Info</A></P>
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Jo, Jea Woong,Yun, Jae Hoon,Bae, Seunghwan,Ko, Min Jae,Son, Hae Jung ELSEVIER 2017 ORGANIC ELECTRONICS Vol.50 No.-
<P><B>Abstract</B></P> <P>To achieve highly efficient organic photovoltaic (OPV) devices, the interface between the photoactive layer and the electrode must be modified to afford the appropriate alignment of the energy levels and to ensure efficient charge extraction at the same time as suppressing charge recombination and accumulation. Recently, <I>p</I>-type conjugated polyelectrolytes (CPEs) have emerged as new hole-transporting materials that can be deposited on electrodes through simple solution processes without additional heat treatment. However, the applications of CPEs have been limited so far because the high electron richness of their conjugated backbones result in low work functions, ∼5.0 eV. Here, by inserting a donor−acceptor (D−A) building block into the CPE backbone, we successfully synthesized a new <I>p</I>-type CPE (PhNa-DTBT), which shows a deep work function above 5.3 eV on several electrodes including Au, Ag, and indium tin oxide. More importantly, PhNa-DTBT produces stable polarons on the polymer backbone and thus achieves a high electrical conductivity of 5.7 × 10<SUP>−4</SUP> S cm<SUP>−1</SUP>. As a result, an OPV incorporating PhNa-DTBT as a hole-transporting layer was found to exhibit a high performance with a power conversion efficiency of 9.29%. Also, the OPV device shows improved stability in air due to the neutral characteristics of the CPE which is favorable for stabilizing neighbored active and electrode layers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New donor-acceptor-type conjugated polyelectrolyte PhNa-DTBT was developed. </LI> <LI> PhNa-DTBT showed a deep work function above 5.3 eV and high electrical conductivity of 5.7 × 10<SUP>−4</SUP> S cm<SUP>−1</SUP>. </LI> <LI> Incorporation of PhNa-DTBT hole-transporting layer into organic solar cells results in improved efficiency (9.29%) and device stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Jo, Jea Woong,Seo, Myung-Seok,Jung, Jae Woong,Park, Joon-Suh,Sohn, Byeong-Hyeok,Ko, Min Jae,Son, Hae Jung Elsevier 2018 Journal of Power Sources Vol.378 No.-
<P><B>Abstract</B></P> <P>The control of the optoelectronic properties of the interlayers of perovskite solar cells (PSCs) is crucial for achieving high photovoltaic performances. Of the solution-processable interlayer candidates, NiO<SUB>x</SUB> is considered one of the best inorganic hole-transporting layer (HTL) materials. However, the power conversion efficiencies (PCEs) of NiO<SUB>x</SUB>-based PSCs are limited by the unfavorable contact between perovskite layers and NiO<SUB>x</SUB> HTLs, the high density of surface trap sites, and the inefficient charge extraction from perovskite photoactive layers to anodes. Here, we introduce a new organic-inorganic double HTL consisting of a Cu:NiO<SUB>x</SUB> thin film passivated by a conjugated polyelectrolyte (PhNa-1T) film. This double HTL has a significantly lower pinhole density and forms better contact with perovskite films, which results in enhanced charge extraction. As a result, the PCEs of PSCs fabricated with the double HTL are impressively improved up to 17.0%, which is more than 25% higher than that of the corresponding PSC with a Cu:NiO<SUB>x</SUB> HTL. Moreover, PSCs with the double HTLs exhibit similar stabilities under ambient conditions to devices using inorganic Cu:NiO<SUB>x</SUB>. Therefore, this organic-inorganic double HTL is a promising interlayer material for high performance PSCs with high air stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Organic-inorganic double hole-transporting layer, Cu:NiO<SUB>x</SUB>/PhNa-1T HTL, was developed. </LI> <LI> Cu:NiO<SUB>x</SUB>/PhNa-1T in perovskite solar cells results in enhanced charge extraction. </LI> <LI> Decreased charge recombination in the perovskite induces enhanced <I>J</I> <SUB>SC</SUB> and FF. </LI> <LI> Devices with Cu:NiO<SUB>x</SUB>/PhNa-1T exhibit good stability under ambient conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Lee, Jea Uk,Kim, Young Do,Jo, Jea Woong,Kim, Jae Pil,Jo, Won Ho Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.43
<P>A new solution processable zinc phthalocyanine dye (ZnPc), as an interface modifier between poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C<SUB>61</SUB>-butyric acid methyl ester (PCBM) in bulk heterojunction solar cells, was successively synthesized and linked to the chain-end of P3HT through the formation of a coordination complex. ZnPc dye molecules do not aggregate but preferentially locate at the interface between P3HT and PCBM, and thus contribute to the photocurrent generation by both direct photo-excitation and enhancement of charge transfer between P3HT and PCBM. To localize the zinc phthalocyanine dyes at the donor–acceptor interface more effectively, another new organic dye molecule, fullerene-functionalized zinc phthalocyanine (ZnPc-C<SUB>60</SUB>) was also synthesized and linked to the chain-end of the P3HT, where ZnPc-C<SUB>60</SUB> contributes not only to the photocurrent generation by direct photo-excitation, but also lowers the interfacial tension, resulting in the reduction of the domain size and the suppression of the macrophase separation of the P3HT/PCBM blend for prolonged thermal annealing. This leads to higher device efficiency with 20% enhancement of the short circuit current and to enhancement of long-term thermal stability of device performance as compared to that of the reference P3HT/PCBM device.</P> <P>Graphic Abstract</P><P>New solution processable zinc phthalocyanine dyes linked at the chain-end of P3HT do not aggregate but preferentially locate at the interface between P3HT and PCBM, and thus contribute to the photocurrent generation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm11563d'> </P>
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