1. Heo S.W.; Le H.H.T.; Tanaka T.; Osaka I.; Takimiya K.; Tajima K.; Cumulative Gain in Organic Solar Cells by Using Multiple Optical Nanopatterns, J. Mater. Chem. A2017, in pressDOI
  2. Huang J.; Nakano K.; Suzuki K.; Chen Y.J.; Wang F.J.; Koganezawa T.; Tajima K.; π-Conjugation Effects of Oligo(thienylenevinylene) Side Chains in Semiconducting Polymers on Photovoltaic Performance, Macromolecules2017, in pressDOI
  3. Chen P.H.; Nakano K.; Suzuki K.; Hashimoto K.; Kikitsu T.; Hashizume D.; Koganezawa T.; Tajima K.; Organic Solar Cells with Controlled Nanostructures Based on Microphase Separation of Fullerene-attached Thiophene-Selenophene Heteroblock Copolymers, ACS Appl. Mater. Interfaces2017, 9, 4758-4768. DOI


  1. Nakano K.; Tajima K.; Organic Planar Heterojunctions: From Models for Interfaces in Bulk Heterojunctions to High-Performance Solar Cells, Adv. Mater.2016, in pressDOI
  2. Nakano K.; Chen Y.J.; Suzuki K.; Tajima K.; Modification of Donor/Acceptor Interface for Efficient Organic Photovoltaics, J. Photopolym. Sci. Tech.2016, 29, 533-536. DOI
  3. Nakano K.; Suzuki K.; Chen Y.J.; Tajima K.; Roles of Energy/Charge Cascades and Intermixed Layers at Donor/Acceptor Interfaces in Organic Solar Cells, Sci. Rep.2016, 6, 29529. DOI
  4. Nakano K.; Nakano M.; Xiao B.; Zhou E.J.; Suzuki K.; Osaka I.; Takimiya K.; Tajima K.; Naphthodithiophene Diimide-Based Copolymers: Ambipolar Semiconductors in Field-Effect Transistors and Electron Acceptors with Near-Infrared Response in Polymer Blend Solar Cells, Macromolecules2016, 49, 1752-1760. DOI
  5. Zhong Y.F.; Suzuki K.; Inoue D.; Hashizume D.; Izawa S.; Hashimoto K.; Koganezawa T.; Tajima K.; Interface-induced Crystallization and Nanostructure Formation of [6,6]-Phenyl-C61-butyric Acid Methyl Ester (PCBM) in Polymer Blend Films and Its Application in Photovoltaics, J. Mater. Chem. A2016, 4, 3335-3341. DOI


  1. Geng Y.F.; Xiao B.; Izawa S.; Huang J.; Tajima K.; Zeng Q.; Zhou E.J.; Fullerene-free Organic Photovoltaics Based on Unconventional Material Combination: A Molecular Donor and Polymeric Acceptors, J. Mater. Chem. A2015, 44, 22325-22331. DOI
  2. Wang F.; Hashimoto K.; Tajima K.; Optical Anisotropy and Strong H-Aggregation of Poly(3-Alkylthiophene) in a Surface Monolayer, Adv. Mater.2015, 39, 6014-6020. DOI RIKEN Research
  3. Izawa S.; Nakano K.; Suzuki K.; Hashimoto K.; Tajima K.; Dominant Effects of First Monolayer Energetics at Donor/Acceptor Interfaces on Organic Photovoltaics, Adv. Mater.2015, 27, 3025-3031. DOI RIKEN Research
  4. Geng Y.F.; Huang J.M.; Tajima K.; Zeng Q.D.; Zhou E.J.; A Low Band Gap n-type Polymer Based on Dithienosilole and Naphthalene Diimide for All-polymer Solar Cells Application, Polymer2015, 63, 164-169. DOI
  5. Zhong Y.F.; Izawa S.; Hashimoto K.; Tajima K.; Koganezawa T.; Yoshida H.; Crystallization-Induced Energy Level Change of [6,6]-Phenyl-C61-Butyric Acid Methyl Ester (PCBM) Film: Impact of Electronic Polarization Energy, J. Phys. Chem. C2015, 119, 23-28. DOI


  1. Geng Y.F.; Cong J.Z.; Tajima K.; Zeng Q.D.; Zhou E.J.; Synthesis and Properties of D–A Copolymers Based on Dithienopyrrole and Benzothiadiazole with Various Numbers of Thienyl Units as Spacers, Polym. Chem.2014, 5, 6797-6803. DOI
  2. Izawa S.; Nishizawa T.; Hashimoto K.; Koganezawa T.; Tajima K.; Separated Crystallization of Donor and Acceptor in Oligo(p-phenylenevinylene)-Naphthalenediimide Dyad Films, Synth. Met.2014, 197, 175-181. DOI
  3. Wei Q.S.; Miyanishi S.; Zhou E.j.; Hashimoto K.; Tajima K.; Poly(4-hexyloxythiazole): A New Low Band Gap Semiconductor for Polymer Electronics, Synth. Met.2014, 196, 139-144. DOI
  4. Zhou E.J.; Nakano M.; Izawa S.; Cong J.Z.; Osaka I.; Takimiya K.; Tajima K.; All-Polymer Solar Cell with High Near-infrared Response Based on A Naphthodithiophene Diimide (NDTI) Copolymer, ACS Macro Lett.2014, 3, 872-875. DOI
  5. Izawa S.; Hashimoto K.; Tajima K.; Surface Functionalization of Organic Semiconductor Films by Segregated Monolayers, Phys. Chem. Chem. Phys.2014, 16, 16383-16387. DOI
  6. Martinez L.; Higuchi S.; Maclachlan A.; Stavrinadis A.; Miller N. C.; Diedenhofen S. L.; Bernechea M.; Sweetnam S.; Nelson J.; Haque S. A.; Tajima K.; Konstantatos G.; Improved Electronic Coupling in Hybrid Organic-inorganic Nanocomposites Employing Thiol-functionalized P3HT and Non-toxic Bismuth Sulfide Nanocrystals, Nanoscale2014, 6, 10018-10026. DOI
  7. Yamamoto S.; Yasuda H.; Ohkita H.; Benten H.; Ito S.; Miyanishi S.; Tajima K.; Hashimoto K.; Charge Generation and Recombination in Fullerene-Attached Poly(3-hexylthiophene)-Based Diblock Copolymer Films, J. Phys. Chem. C2014, 118, 10584-10589. DOI
  8. Ma J.S.; Hashimoto K.; Koganezawa T.; Tajima K.; Enhanced Vertical Carrier Mobility in Poly(3-alkylthiophene) Thin Films Sandwiched with Self-assembled Monolayer and Surface-segregated Layer, Chem. Commun.201450, 3627-3630. DOI
  9. Zhong Y.F.; Tada A.;  Izawa S.; Hashimoto K.; Tajima K.; Enhancement of VOC without Loss of JSC in Organic Solar Cells by Modification of Donor/Acceptor Interfaces, Adv. Energy Mater. 2014, 4, 1301332. DOI


  1. Zhou E.J.; Hashimoto K.; Tajima K.; Low Band Gap Polymers for Photovoltaic Device with Photocurrent Response Wavelengths over 1000 nm, polymer201354, 6501-6509. DOI
  2. Zhou E.J.; Cong, J.Z.;  Hashimoto K.; Tajima K.; Control of Miscibility and Aggregation via Material Design and Coating Process for High-Performance Polymer Blend Solar Cell, Adv. Mater. 201325, 6991–6996. DOI
  3. Geng Y.F.; Ma J.S.; Wei Q.S.; Hashimoto K.; Tajima K.; Effects of Side Chain Sequence on Surface Segregation of Regioregular Poly (3-alkylthiophene) and Interfacial Modification of Bilayer Organic Photovoltaic Devices, J. Mater. Chem. A 20131, 11867-11873. DOI
  4. Zhong Y.F.; Tada A.;  Geng Y.F.; Wei Q.S.; Hashimoto K.; Tajima K.; Donor/Acceptor Interface Modifications in Organic Solar Cells, J. Photopolym. Sci. Tech. 201326, 181-184. DOI
  5. Ma J.S.; Hashimoto K.; Koganezawa T.; Tajima K.; End-On Orientation of Semiconducting Polymers in Thin Films Induced by Surface Segregation of Fluoroalkyl Chains, J. Am. Chem. Soc. 2013135, 9644-9647. DOI
  6. Martinez L.; Stavrinadis A.; Higuchi S.; Diedenhofen S. L.; Bernechea M.; Tajima K.; Konstantatos G.; Hybrid Solution-processed Bulk Heterojunction Solar Cells Based on Bismuth Sulfide Nanocrystals, Phys. Chem. Chem. Phys. 201315, 5482-5487. DOI
  7. Zhao M.X.; Hashimoto K.; Tajima K.; Synthesis of Copolymer Based on Naphthalene Diimide Connected with a Non-conjugated Flexible Linker, Synth. Met. 2013, 175, 9-14. DOI
  8. Zhao M.X.; Hashimoto K.; Tajima K.; Organic Electronic Devices with Copolymers Based on Naphthalene Diimide Connected with Non Conjugated Flexible Linker, Jpn. J. Appl. Phys.201352, 05DA15. DOI
  9. Ma J.S.; Geng Y.F.; Hashimoto K.; Tajima K.; Synthesis and Characterization of End-Functionalized Poly(3-butylthiophene) with Semifluoroalkyl Chains, Macromol. Chem. Phys. 2013, 214, 1326–1331. DOI
  10. Zhou E.J.; Cong, J.Z.; Hashimoto K.; Tajima K.; A Benzoselenadiazole-Based Low Band Gap Polymer: Synthesis and Photovoltaic Application, Macromolecules201346, 763–768. DOI
  11. Zhong Y.F.; Ma J.S.; Hashimoto K.; Tajima K.; Electric Field-Induced Dipole Switching at the Donor/Acceptor Interface in Organic Solar Cells, Adv. Mater. 2013, 25, 1071-1075. DOI


  1. Zhou E.J.; Cong, J.Z.; Hashimoto K.; Tajima K.; Introduction of a Conjugated Side Chain as an Effective Approach to Improving Donor-Acceptor Photovoltaic Polymers, Energy Environ. Sci.20125, 9756-9759.  DOI
  2. Izawa S.; Hashimoto K.; Tajima K.; Synthesis, Characterization, and Photovoltaic Properties of Diketopyrrolopyrrole-oligothiophene/Fullerene Dyads, Synth. Met.2012162, 2201-2205. DOI
  3. Izawa S.; Hashimoto K.; Tajima K.; Morphological Stability of Organic Solar Cells Based upon Oligo(p-phenylenevinylene)-C70 Dyad,Phys. Chem. Chem. Phys.201214, 16138-16142. DOI
  4. Miyanishi S.; Zhang Y.; Hashimoto K.; Tajima K.; Controlled Synthesis of Fullerene-Attached Poly(3-alkylthiophene)-Based Copolymers for Rational Morphological Design in Polymer Photovoltaic Devices, Macromolecules201245, 6424−6437.  DOI
  5. Zhou E.J.; Cong J.Z.; Zhao M.X.; Zhang L.Z.; Hashimoto K.; Tajima K.; Synthesis and application of poly(fluorene-alt-naphthalene diimide) as an n-type polymer for all-polymer solar cells,  Chem. Commun.201248, 5283-5285.  DOI
  6. Tada A.; Geng Y.F.; Nakamura M.; Wei Q.-S.,Hashimoto K.; Tajima K.; Interfacial modification of organic photovoltaic devices by molecular self-organization. Phys. Chem. Chem. Phys.2012, 14, 3713 - 3724. DOI
  7. Zhang L.Z.; Hashimoto K.; Tajima K.; End-group stannylation of regioregular poly(3-hexylthiophene)s. Polymer J.201244, 1145–1148. DOI
  8. Zhang L.Z.; Zhang Y.; Wei Q.S.; Zhou E.J.; Yang C.H.; Hashimoto K.; Tajima K.; Effects of Block Length in Copolymers Based on Regioregular Oligothiophenes Linked with Electron-Accepting Units. Macromol. Rapid Commun.2012,  33, 658-663. DOI
  9. Zhou E.J.; Cong J.Z.; Tajima K., Yang C.H.; Hashimoto K.; Conjugated Polymers Based on 1,3-Dithien-2-yl-thieno[3,4-c]pyrrole-4,6-dione: Synthesis, Characterization,and Solvent Effects on Photovoltaic Performance. J. Phys. Chem. C2012116, 2608–2614. DOI


  1. Yang C.H.; Zhou E.J.; Miyanishi S.; Hashimoto K.;Tajima K.; Preparation of Active Layers in Polymer Solar Cells by Aerosol Jet Printing. ACS Appl. Mater. Interface, 20113, 4053–4058. DOI
  2. Geng Y.F.; Hashimoto K.; Tajima K.; Synthesis of Regioregular Poly(3-alkylthiophene) with Alternating Dodecyl/1H,1H,2H,2H-Perfluorooctyl Side Chains. Macromol. Rapid Commun.201132, 1478–1483. DOI
  3. Zhang L.Z.; Tajima K.; Hashioto K.; Low Bandgap Polymers Based on Regioregular Oligothiophenes Linked with Electron-Accepting Units. Macromolecules201144, 4222–4229. DOI
  4. Izawa S.; Tajima K.; Hashimoto K.; Efficient Charge Generation and Collection in Organic Solar Cells Based on Low Band Gap Dyad Molecules. Chem. Commun.201147, 6365-6367. DOI
  5. Sato S.; Tajima K.; Hashimoto K.; Synthesis and Photovoltaic Application of Donor-acceptor Type Copolymers Containing 9-Cyanomethylenefluorene Derivatives with Chemically Tunable Electronic Properties. Synth. Met. 2011161, 1289-1298. DOI (Cover Picture)
  6. Geng Y.F.; Hashimoto K.; Tajima K.; Dipole Layer Formation by Surface Segregated Monolayer of Poly(3-alkylthiophene) with Alternating Semifluoroalkyl Side Chains. Chem. Mater., 201123, 4257–4263. DOI
  7. Tada A.; Geng Y.F.; Wei Q.S.; Hashimoto K.; Tajima K.; Tailoring organic heterojunction interfaces in bilayer polymer photovoltaic devices. Nature Mater.201110, 450–455. DOI
  8. Wei Q.S.; Hashimoto K.; Tajima K.; Experimental Investigation of Charge Carrier Transport in Organic Thin-film Transistors with "Buried Surface Layers". ACS Appl. Mater. Interfaces2011, 3, 139–142. DOI
  9. Zhang Y.; Tajima K.; Hashimoto K.; Field-effect Hole Mobility of Poly(3-hexylthiophene-block-3-(2-ethylhexyl)thiophene)s. Synth. Met.,2011, 161, 225-228 (Cover Picture). DOI.
  10. Zhou E.J.; Cong J.Z.; Wei Q.S.; Tajima K.; Yang C.H.; Hashimoto K.; All-Polymer Solar Cells Based on Perylene Diimide–Based Copolymers: Material Design and Phase Separation Control, Angew. Chem. Int. Ed.2011, 50, 2799-2803. DOI
  11. Zhou E.J.; Cong J.Z.; Tajima K.; Yang C.H.; Hashimoto K.; Synthesis and Photovoltaic Properties of Donor-Acceptor Copolymer based on Dithienopyrrole and Thienopyrroledione. Macromol. Chem. Phys.2011, 212, 305-310. DOI
  12. Tajima K.; Hashimoto K.; Nanostructure Control in Polymer Solar Cells by Self-Organization. Chem. Rec.2011, 11, 8-17. DOI
  13. Yan X.; Li B.S.; Cui X.;Wei Q.S.; Tajima K.; Li L.S.; Independent Tuning of the Band Gap and Redox Potential of Graphene Quantum Dots. J. Phys. Chem. Lett.2011, 2, 1119-1124. DOI


  1. Zhou, E.J.; Cong, J.Z.; Tajima K.; Hashimoto K.; Synthesis and Photovoltaic Properties of Donor-Acceptor Copolymers Based on 5,8-Dithien-2-yl-2,3-diphenylquinoxaline. Chem. Mater., 2010, 22, 4890–4895. DOI
  2. Miyanishi S.; Zhang Y.; Tajima K.; Hashimoto K.; Fullerene Attached All-Semiconducting Diblock Copolymers for Stable Single Component Polymer Solar Cells. Chem. Commun.2010, 46, 6723-6725. DOI
  3. Wei Q. S.; Tajima, K.; Hashimoto, K., Electrical Instability of Polymer Thin-Film Transistors Using Contact Film Transfer Methods. Appl. Phys. Lett.2010, 96, 243301. DOI
  4. Zhou, E. J.; Cong, J.Z.; Yamakawa. S.; Wei Q.S.; Nakamura. M.; Tajima, K; Yang, C. H.; Hashimoto, K., Synthesis of Thieno[3,4-b]pyrazine-Based and 2,1,3-Benzothiadiazole-Based Donor−Acceptor Copolymers and their Application in Photovoltaic Devices. Macromolecules2010, 43, 2873-2879. DOI
  5. Zhou, E. J.;Tajima, K; Yang, C. H.; Hashimoto, K., Band gap and molecular energy level control of perylene diimide-based donor–acceptor copolymers for all-polymer solar cells.  J. Mater. Chem., 2010, 12, 2362-2368. DOI
  6. Zhou, E. J.; Wei, Q. S.; Yamakawa, S; Zhang, Y; Tajima, K; Yang, C. H.; Hashimoto, K., Diketopyrrolopyrrole-based Semiconducting Polymers for Photovoltaic Device with Photocurrent Response Wavelengths up to 1.1 μm. Macromolecules2010, 43, 821-826. DOI


  1. Nakamura, M.; Yang, C. H.; Zhou, E. J.; Tajima, K.; Hashimoto, K.,  Polymer Bulk Heterojunction Photovoltaic Devices with Multilayer Structures Prepared by Thermal Lamination. ACS Appl. Mater. Interfaces2009, 1, 2703. DOI
  2. Wei, Q. S.; Miyanishi, S.; Tajima, K.; Hashimoto, K., Enhanced Charge Transport in Polymer Thin-Film Transistors Prepared by Contact Film Transfer Method. ACS Appl. Mater. Interfaces2009, 1, 2660. DOI
  3. Wei, Q. S.; Tajima, K.; Tong, Y. J.; Ye, S.; Hashimoto, K.,  Surface-Segregated Monolayers: A New Type of Ordered Monolayer for Surface Modification of Organic Semiconductors. J. Am. Chem. Soc.2009, 131, 19597. DOI
  4. Zhou, E. J.; Yamakawa, S.; Zhang, Y.; Tajima, K.; Yang, C. H.; Hashimoto, K., Indolo[3,2-b]carbazole-based Alternating Donor-acceptor Copolymers: Synthesis, Properties and Photovoltaic Application. J. Mater. Chem. 2009, 19, 7730. DOI
  5. Zhou, E. J.; Yamakawa, S. P.; Tajima, K.; Yang, C. H.; Hashimoto, K., Synthesis and Photovoltaic Properties of Diketopyrrolopyrrole-Based Donor-Acceptor Copolymers. Chem. Mater. 2009, 21, 4055. DOI
  6. Wei, Q. S.; Tajima, K.; Hashimoto, K., Bilayer Ambipolar Organic Thin-Film Transistors and Inverters Prepared by the Contact-Film-Transfer Method. ACS Appl. Mater. Interfaces 2009, 1, 1865. DOI
  7. Zhang, Y.; Tajima, K.; Hashimoto, K., Nanostructure Formation in Poly(3-hexylthiophene-block3-(2-ethylhexyl)thiophene)s.Macromolecules 2009, 42, 7008. DOI
  8. Nakamura, M.; Yang, C. H.; Tajima, K.; Hashimoto, K., High-performance Polymer Photovoltaic Devices with Inverted Structure Prepared by Thermal Lamination. Sol. Energy Mater. Sol. Cells 2009, 93, 1681. DOI
  9. Nishizawa, T.; Lim, H. K.; Tajima, K.; Hashimoto, K., Efficient Dyad-based Organic Solar Cells with a Highly Crystalline Donor Group. Chem. Commun. 2009, 2469. DOI
  10. Yamakawa, S.; Tajima, K.; Hashimoto, K., Buffer Layer Formation in Organic Photovoltaic Cells by Self-organization of Poly(dimethylsiloxane)s. Org. Electron. 2009, 10, 511. DOI
  11. Miyanishi, S.; Tajima, K.; Hashimoto, K., Morphological Stabilization of Polymer Photovoltaic Cells by Using Cross-Linkable Poly(3-(5-hexenyl)thiophene). Macromolecules 2009, 42, 1610. DOI
  12. Sato, S.; Tajima, K.; Hashimoto, K., Synthesis and Characterization of Regioregular Cyano-Substituted Poly(p-phenylenevinylene).Macromolecules 2009, 42, 1785. DOI
  13. Nishizawa, T.; Lim, H. K.; Tajima, K.; Hashimoto, K., Highly Uniaxial Orientation in Oligo(p-phenylenevinylene) Films Induced During Wet-Coating Process. J. Am. Chem. Soc. 2009, 131, 2464. DOI


  1. Zhou, E. J.; Nakamura, M.; Nishizawa, T.; Zhang, Y.; Wei, Q. S.; Tajima, K.; Yang, C. H.; Hashimoto, K., Synthesis and Photovoltaic Properties of a Novel Low Band Gap Polymer Based on N-Substituted Dithieno[3,2-b:2 ',3 '-d]pyrrole. Macromolecules 2008, 41, 8302.  DOI
  2. Takanezawa, K.; Tajima, K.; Hashimoto, K., Charge Separation Interfaces in Polymer Photovoltaic Devices Hybridized with ZnO Nanorod Arrays. Jpn. J. Appl. Phys. 2008, 47, 8049. DOI 
  3. Nishizawa, T.; Tajima, K.; Hashimoto, K., The Effect of Crystallinity in Donor Groups on the Performance of Photovoltaic Devices Based on an Oligothiophene-fullerene Dyad. Nanotechnology 2008, 19, 424017. DOI
  4. Takanezawa, K.; Tajima, K.; Hashimoto, K., Efficiency Enhancement of Polymer Photovoltaic Devices Hybridized with ZnO Nanorod Arrays by the Introduction of a Vanadium Oxide Buffer Layer. Appl. Phys. Lett. 2008, 93, 063308. DOI 
  5. Wei, Q. S.; Nishizawa, T.; Tajima, K.; Hashimoto, K., Self-organized Buffer Layers in Organic Solar Cells. Adv. Mater. 2008, 20, 2211. DOI
  6. Tajima, K.; Suzuki, Y.; Hashimoto, K., Polymer Photovoltaic Devices Using Fully Regioregular Poly[(2-methoxy-5-(3 ',7 '-dimethyloctyloxy))-1,4-phenylenevinylene]. J. Phys. Chem. C 2008, 112, 8507. DOI
  7. Zhang, Y.; Tajima, K.; Hirota, K.; Hashimoto, K., Synthesis of All-conjugated Diblock Copolymers by Quasi-living Polymerization and Observation of Their Microphase Separation. J. Am. Chem. Soc. 2008, 130, 7812. DOI


  1. Suzuki, Y.; Hashimoto, K.; Tajima, K., Synthesis of Regioregular Poly(p-henylenevinylene)s by Horner Reaction and Their Regioregularity Characterization. Macromolecules 2007, 40, 6521. DOI
  2. Nishizawa, T.; Tajima, K.; Hashimoto, K., Supramolecular Formation of Fibrous Nanostructure in Donor-acceptor Dyad. J. Mater. Chem. 2007, 17, 2440. DOI
  3. Takanezawa, K.; Hirota, K.; Wei, Q. S.; Tajima, K.; Hashimoto, K., Efficient Charge Collection with ZnO Nanorod Array in Hybrid Photovoltaic Devices. J.Phys. Chem. C 2007, 111, 7218. DOI
  4. Hirota, K.; Tajima, K.; Hashimoto, K., Physicochemical Study of Discotic Liquid Crystal Decacyclene Derivative and Utilization in Polymer Photovoltaic Devices. Synth. Met. 2007, 157, 290. DOI


  1. Wei, Q. S.; Hirota, K.; Tajima, K.; Hashimoto, K., Design and Synthesis of TiO2 Nanorod Assemblies and Their Application for Photovoltaic Devices. Chem. Mater. 2006, 18, 5080. DOI
  2. Kida, K.; Hirota, K.; Tajima, K.; Hashimoto, K., Photocatalytic Printing of Nanostructures on TiO2 Using Diblock Copolymer. Chem. Mater. 2006, 18, 1386. DOI


  1. Hirota, K.; Tajima, K.; Hashimoto, K., Facile Preparation of Nanoelectrode Ensembles Using Amphiphilic Block Copolymer Film. Langmuir 2005, 21, 11592. DOI