Lijun Huo

Publications (24)138.69 Total impact

• Article: PDT-S-T: A New Polymer with Optimized Molecular Conformation for Controlled Aggregation and π-π Stacking and Its Application in Efficient Photovoltaic Devices.

  Yue Wu, Zhaojun Li, Wei Ma, Ye Huang, Lijun Huo, Xia Guo, Maojie Zhang, Harald Ade, Jianhui Hou
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  ABSTRACT: The correlation among molecular conformation, the crystallinity of the morphology, propensity for π-π stacking, J- versus H-aggregation, and photovoltaic performance have been studied based on two newly designed polymers, PBDTTT-S-T and PDT-S-T. The results show that more linear backbone structure is helpful to improve photovoltaic properties of the polymer, and therefore, molecular conformation should be considered for molecular design of photovoltaic polymers.
  Advanced Materials 05/2013; · 13.88 Impact Factor
• Article: Influence of D/A Ratio on Photovoltaic Performance of a Highly Efficient Polymer Solar Cell System.

  Xia Guo, Maojie Zhang, Jiahui Tan, Shaoqing Zhang, Lijun Huo, Wenping Hu, Yongfang Li, Jianhui Hou
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  ABSTRACT: A new copolymer PIDTDTQx based on indacenodithiophene and quinoxaline is synthesized and characterized. The correlation between the D/A ratio, mobility, and photovoltaic properties, as well as morphology of the D/A blend based on a PIDTDTQx:PC(70) BM system is investigated. The power conversion efficiency of the polymer solar cells based on PIDTDTQx/PC(70) BM (1:4, w/w) reaches 7.51%.
  Advanced Materials 10/2012; · 13.88 Impact Factor
• Article: Improving the ordering and photovoltaic properties by extending π-conjugated area of electron-donating units in polymers with D-A structure.

  Ye Huang, Xia Guo, Feng Liu, Lijun Huo, Yuning Chen, Thomas P Russell, Charles C Han, Yongfang Li, Jianhui Hou
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  ABSTRACT: A systematic molecular design process from PBDTTT-S to PBDTDTTT-S-T, a high-performance semiconducting polymer for organic photovoltaics, has been achieved by enhancing structural order, self-assembly and carrier mobility. Solar cells made from PBDTDTTT-S-T blended with PC(70) BM show a power conversion efficiency (PCE) of 7.81%, which is 25% higher than that of the parent PBDTTT-S.
  Advanced Materials 05/2012; 24(25):3383-9. · 13.88 Impact Factor
• Source

  Available from: Xuanhua Li

  Article: Dual plasmonic nanostructures for high performance inverted organic solar cells.

  Xuanhua Li, Wallace C H Choy, Lijun Huo, Fengxian Xie, Wei E I Sha, Baofu Ding, Xia Guo, Yongfang Li, Jianhui Hou, Jingbi You, Yang Yang
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  ABSTRACT: Dual plasmonic metallic nanostructures in organic solar cells are demonstrated by simultaneously incorporating gold nanoparticles (NPs) into the active layer and fabricating the silver nanograting electrode by means of a vacuum-assisted nanoimprinting method. Apart from the waveguide modes and diffraction, hybridized surface plasmonic resonances (SPRs, from the Ag nanograting) and localized plasmonic resonances (LPRs, from the Au NPs) are simultaneously introduced to successfully achieve a high power conversion efficiency (PCE).
  Advanced Materials 05/2012; 24(22):3046-52. · 13.88 Impact Factor
• Article: Synthesis of a 4,8-dialkoxy-benzo[1,2-b:4,5-b']difuran unit and its application in photovoltaic polymer.

  Lijun Huo, Ye Huang, Benhu Fan, Xia Guo, Yan Jing, Maojie Zhang, Yongfang Li, Jianhui Hou
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  ABSTRACT: A new building block of benzo[1,2-b:4,5-b']difuran (BDF) was firstly designed and synthesized. The newly designed unit was applied for constructing a new photovoltaic low band gap polymer, PBDFDTBT, which exhibited promising power conversion efficiency of 5.0%.
  Chemical Communications 03/2012; 48(27):3318-20. · 6.17 Impact Factor
• Article: Replacing alkoxy groups with alkylthienyl groups: a feasible approach to improve the properties of photovoltaic polymers.

  Lijun Huo, Shaoqing Zhang, Xia Guo, Feng Xu, Yongfang Li, Jianhui Hou
  Angewandte Chemie International Edition 10/2011; 50(41):9697-702. · 13.45 Impact Factor
• Article: Synthesis of a polythieno[3,4-b]thiophene derivative with a low-lying HOMO level and its application in polymer solar cells.

  Lijun Huo, Xia Guo, Yongfang Li, Jianhui Hou
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  ABSTRACT: A planar benzodithiophene with lower HOMO was copolymerized with the thieno[3,4-b]thiophene unit to obtain a new low band gap polymer of PBDPTT-C, which exhibited a higher open-circuit voltage (V(oc)) of 0.8 V and a promising efficiency of 5.2%.
  Chemical Communications 06/2011; 47(31):8850-2. · 6.17 Impact Factor
• Article: Sulfonyl: a new application of electron-withdrawing substituent in highly efficient photovoltaic polymer.

  Ye Huang, Lijun Huo, Shaoqing Zhang, Xia Guo, Charles C Han, Yongfang Li, Jianhui Hou
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  ABSTRACT: A strong electron-withdrawing group, sulfonyl, was firstly introduced to a semiconducting polymer, PBDTTT-S. The PCE of the PBDTTT-S device reached 6.22% with a high open-circuit voltage of 0.76 V. The sulfonyl group is thus a promising candidate as a strong electron-withdrawing group applied to high-efficiency PSCs.
  Chemical Communications 06/2011; 47(31):8904-6. · 6.17 Impact Factor
• Source

  Available from: Zhixiang Peng

  Article: Antimicrobial and DNA-binding activities of the peptide fragments of human lactoferrin and histatin 5 against Streptococcus mutans.

  Lijun Huo, Kai Zhang, Junqi Ling, Zhixiang Peng, Xiangya Huang, Hongyan Liu, Lisha Gu
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  ABSTRACT: To investigate the killing effect of two salivary antimicrobial peptides, hLF1-11 and P-113, and identify the antibacterial mechanism of the peptides. The antimicrobial activities of hLF1-11 and P-113 against oral Streptococci strains were determined using the broth microdilution method. The effects of hLF1-11 and P-113 on the bacterial plasma membrane were visualized by scanning electron microscopy. Cell membrane permeability was monitored using the intracellular dye calcein. The subcellular localization of hLF1-11 and P-113 in bacteria was measured by fluorescence light microscopy. An electrophoretic mobility shift assay (EMSA) was performed to evaluate the DNA binding capabilities of hLF1-11, P-113 and MUC7 12-mer. Both hLF1-11 and P-113 exerted potent bactericidal activities against all selected oral Streptococci. Streptococcus mutans UA 159 was the most susceptible of the oral bacterial species tested to the antimicrobial effects of the three peptides. The cell membranes of bacteria treated with hLF1-11 or P-113 were still intact after 30 min. hLF1-11 and P-113 could penetrate the bacterial cell membranes and accumulate in the cytoplasm in S. mutans. Both hLF1-11 and P-113 showed DNA binding affinity. Together, our results demonstrate that hLF1-11 and P-113 display antibacterial activity against dental cavity-inducing S. mutans through an intracellular mechanism that could involve DNA binding. Thus, these peptides might be attractive and valuable candidates for development into effective antimicrobial therapies to combat dental caries.
  Archives of oral biology 03/2011; 56(9):869-76. · 1.65 Impact Factor
• Source

  Available from: ucla.edu

  Article: A polybenzo[1,2-b:4,5-b']dithiophene derivative with deep HOMO level and its application in high-performance polymer solar cells.

  Lijun Huo, Jianhui Hou, Shaoqing Zhang, Hsiang-Yu Chen, Yang Yang
  Angewandte Chemie International Edition 02/2010; 49(8):1500-3. · 13.45 Impact Factor
• Source

  Available from: ucla.edu

  Article: Low band gap dithieno[3,2-b:2',3'-d]silole-containing polymers, synthesis, characterization and photovoltaic application.

  Lijun Huo, Hsiang-Yu Chen, Jianhui Hou, Teresa L Chen, Yang Yang
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  ABSTRACT: A series of low band gap silole-containing polymers were synthesized with different alkyl side chains and a power conversion efficiency (PCE) of 3.43% was obtained.
  Chemical Communications 10/2009; · 6.17 Impact Factor
• Article: Bandgap and Molecular Level Control of the Low-Bandgap Polymers Based on 3,6-Dithiophen-2-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione toward Highly Efficient Polymer Solar Cells

  Lijun Huo, Jianhui Hou, Hsiang-Yu Chen, Shaoqing Zhang, Yang Jiang, Teresa L. Chen, Yang Yang
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  ABSTRACT: A series of low-bandgap polymers based on a soluble chromophore of 3,6-dithiophen-2-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP) unit were synthesized by introducing of different electron-rich building blocks copolymerized with DPP unit. Four new DPP-based polymers, PDPP-DTS, PDPP-F, PDPP-BDT, and PDPP-BDP, were characterized by GPC, TGA, NMR, UV−vis absorption, and electrochemical cyclic voltammetry. The results indicate that their bandgaps as well as their molecular energy levels are readily tuned by copolymerizing with different conjugated electron-donating units. In order to investigate their photovoltaic properties, polymer solar cell (PSC) devices based on PDPP-DTS, PDPP-F, PDPP-BDT, and PDPP-BDP were fabricated with a structure of ITO/PEDOT:PSS/polymers:PC70BM(1:2,w/w)/Ca/Al under the illumination of AM 1.5G, 100 mW/cm2. The power conversion efficiencies (PCE) of the four DPP-based PSC devices were measured and shown in this paper. The best performance of the PSC device was obtained by using PDPP-BDP as the electron donor material, and a PCE of 4.45% with an open-circuit voltage (Voc) of 0.72 V, a short-circuit current (Jsc) of 10.0 mA/cm2, and a fill factor (FF) of 61.8% was achieved, which is the best result among the DPP-based polymer materials. It is apparent that the PDPP-BDP-based device exhibits a very broad response range, covering from 300 to 850 nm. The results of the solar cells indicate that these types of materials are very promising candidates for highly efficient polymer solar cells.
  08/2009;
• Article: Improvement of Photoluminescent and Photovoltaic Properties of Poly(thienylene vinylene) by Carboxylate Substitution

  Lijun Huo, Teresa L. Chen, Yi Zhou, Jianhui Hou, Hsiang-Yu Chen, Yang Yang, Yongfang Li
  07/2009;
• Article: Alkylthio-substituted polythiophene: absorption and photovoltaic properties.

  Lijun Huo, Yi Zhou, Yongfang Li
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  ABSTRACT: Two polythiophene derivatives with electron-donating alkylthio side chains, poly[(3-hexylthio)thiophene] (P3HST) and poly[(3-hexylthio)thiophene-alt-thiophene] (P3HST-co-Th) have been synthesized and characterized. Both P3HST and P3HST-co-Th show broader absorption peaks than poly(3-hexylthiophene). Meanwhile, the alkylthio side chains decrease the HOMO energy level of the polymers, which benefits the higher open circuit voltage of the polymer solar cells (PSCs) based on the polymer as donor. PSCs have been fabricated with the polymers as donor and [6,6]-phenyl C61 butyric acid methyl ester as acceptor (1: 1, w/w). The devices based on P3HST and P3HST-co-Th show an open circuit voltage of 0.63 V, and a power conversion efficiency of 0.34% and 0.5%, respectively, under the illumination of AM1.5, 80 mW · cm(-2) .
  Macromolecular Rapid Communications 06/2009; 30(11):925-31. · 4.60 Impact Factor
• Article: Polythiophene derivative with the simplest conjugated-side-chain of alkenyl: synthesis and applications in polymer solar cells and field-effect transistors.

  Yu Huang, Ying Wang, Guangyi Sang, Erjun Zhou, Lijun Huo, Yunqi Liu, Yongfang Li
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  ABSTRACT: A polythiophene derivative with the simplest conjugated side chain, poly(3-hexy-1-enylthiophene) (P3HET), was synthesized by Stille self-coupling reaction. A comparative study of the newly synthesized polymer with poly(3-hexylthiophene) (P3HT), one of the most widely investigated optoelectronic materials, is presented. The effect of double bond (C=C) on the side chain toward thermal stability and optical and electronic properties was fully characterized by TGA, UV-vis absorption spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. The hole mobility of P3HET determined by the space-charge-limited current (SCLC) model is 6.7 x 10(-3) cm(2)/V s, which is comparable to P3HT with similar molecular weight and regularity and 1 order of magnitude higher than most conjugated-side-chain polythiophene derivatives. Polymer solar cells (PSCs) and field effect transistors (FETs) were fabricated respectively to exploit its potential applications in optoelectronic devices.
  The Journal of Physical Chemistry B 11/2008; 112(43):13476-82. · 3.70 Impact Factor
• Article: Novel two‐dimensional donor–acceptor conjugated polymers containing quinoxaline units: Synthesis, characterization, and photovoltaic properties

  Lijun Huo, Zhan'ao Tan, Xiang Wang, Yi Zhou, Minfang Han, Yongfang Li
  Journal of Polymer Science Part A Polymer Chemistry 05/2008; 46(12):4038 - 4049. · 3.92 Impact Factor
• Article: A phenylenevinylene‐thiophene‐phenyleneethynylene copolymer: synthesis, characterization, and photovoltaic properties

  Yingping Zou, Zhan'ao Tan, Lijun Huo, Yongfang Li
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  ABSTRACT: A phenylenevinylene-thiophene-phenyleneethynylene copolymer, poly{[1′,4′-bis-(thienyl-vinyl)]-2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene-vinylene-alt-1,4-dioctyloxyl-phenyleneethynylene}(PTPPV- PPE), was synthesized by the Sonogashira Pd-catalyzed cross-coupling reaction. The copolymer possesses higher thermal decomposition temperature (Td = 382°C) compared with poly{[1′,4′-bis- (thienyl-vinyl)]-2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene-vinylene} (PTPPV). The absorption and photoluminescence (PL) peaks of PTPPV-PPE solution and solid film locate in between those of the homopolymers of PTPPV and poly(1,4-dioctyloxyl-phenyleneethynylene) (PPE), and closer to that of PTPPV. Photovoltaic cell was fabricated based on the blend of PTPPV-PPE and PCBM with a weight ratio of 1:1. The primary result shows an open circuit voltage (Voc) of 0.72 V which is higher than that of the PTPPV (0.67 V), and a power conversion efficiency (PCE) of 0.3% under the illumination of AM1.5, 100 mW/cm2 which is much better than that of PPEs. Copyright © 2008 John Wiley & Sons, Ltd.
  Polymers for Advanced Technologies 01/2008; 19(7):865 - 871. · 2.01 Impact Factor
• Article: Alternating copolymers of electron‐rich arylamine and electron‐deficient 2,1,3‐benzothiadiazole: Synthesis, characterization and photovoltaic properties

  Lijun Huo, Chang He, Minfang Han, Erjun Zhou, Yongfang Li
  Journal of Polymer Science Part A Polymer Chemistry 07/2007; 45(17):3861 - 3871. · 3.92 Impact Factor
• Article: Poly(quinoxaline vinylene) With Conjugated Phenylenevinylene Side Chain: A Potential Polymer Acceptor With Broad Absorption Band

  Lijun Huo, Zhan'ao Tan, Yi Zhou, Erjun Zhou, Minfang Han, Yongfang Li
  Macromolecular Chemistry and Physics 06/2007; 208(12):1294 - 1300. · 2.36 Impact Factor
• Article: Synthesis, Hole Mobility, and Photovoltaic Properties of Cross-Linked Polythiophenes with Vinylene−Terthiophene−Vinylene as Conjugated Bridge

  Erjun Zhou, Zhan'ao Tan, Yi Yang, Lijun Huo, Yingping Zou, Chunhe Yang, Yongfang Li
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  ABSTRACT: A class of cross-linked polythiophenes with different ratio (2%, 4%, 8%) of vinylene−terthiophene−vinylene (VTThV) conjugated bridges (PT−VTThV2, PT−VTThV4, and PT−VTThV8) were synthesized. The cross-linking influenced the absorption spectra of the polymer solutions very little, but it resulted in blue-shift of the absorption spectra of the polymer films by ca. 28−39 nm. Cyclic voltammograms display that the p-doping/dedoping and n-doping/dedoping processes of all the cross-linked polythiophenes are reversible and the electrochemical bandgaps increased a little with the increase of the content of the conjugated bridges. The hole mobility values determined from the space-charge-limited current (SCLC) model reached 4.70 × 10-3 for PT−VTThV2, 2.58 × 10-3 for PT−VTThV4, and 9.48 × 10-4 cm2/(V s) for PT−VTThV8, respectively. The hole mobility of PT−VTThV2 with 2% VTThV conjugated bridges is about three orders higher than that of the corresponding polymer P1 without the conjugated bridges. The power conversion efficiency of the polymer solar cell based on the blend of PT−VTThV2 and PCBM (1:1, w/w) reached 1.72% under the illumination of AM 1.5, 100 mW/cm2, which is two times of that of the device based on P1. The results indicate that the cross-linking with the VTThV conjugated bridges obviously improved charge transportation the photovoltaic properties of the conjugated polymers.
  02/2007;