溶剂沸点对聚(3-己基噻吩)薄膜内链结构与分子取向的影响
|
摘要
以聚(3-己基噻吩)(P3HT)为研究对象,借助荧光相关光谱、紫外-可见光谱和掠角红外光谱考察了溶剂性质对旋涂膜内P3HT的链结构与分子取向的影响。结果表明:溶液中P3HT的分子链构象受溶解度的影响,当P3HT溶解在溶解性好的良溶剂中时,链构象更伸展;固体薄膜内P3HT的物理结构却不受其在溶剂中溶解度大小的影响而具有沸点依赖性,溶解在高沸点溶剂中的P3HT旋涂后,薄膜内P3HT主链平面性与π-π相互作用均得到提高;此外,溶剂沸点的增加导致分子取向由"面朝上"方式转变为"边朝上"方式。
Poly(3-hexylthiophene)(P3HT)used in organic field effect transistors,polymer solar cells and so on has received continuous attentions.The conformation of individual chains and the degree of theπ-πstacking are considered to be the important factors to determine the device performance.As the solutionprocessing material,there is no doubt that the solvent properties such as solubility and boiling-point affect the structures of P3HT solid film.However,there is no consistent conclusion that which factor makes the main contribution.In this work,by using Fluorescence correlation spectroscopy,UV-Vis spectroscopy,and reflection-absorption infrared spectroscopy,the effect of the solvent properties on the P3HT lamellar structure in the solid film is investigated.Four different solvents,carbon disulfide,chloroform,toluene and chlorobenzene,were employed.P3HT molecules show more extended conformation in the good solvents of carbon disulfide and chlorobenzene,which show higher solubility to P3HT,compared to the poor solvents of toluene and chloroform.However,in the solid state,the solvent boiling-point plays the important role in the lamellar structure.Firstly,the better backbone planarity comes from the film deposited from the solution in which the solvent has higher boiling-point.Furthermore,theπ-πinteraction between adjacent molecular chains is also improved with the increasing of solvent boiling-point.Besides,the molecular orientation is also affected by the solvent boiling-point.The prolonged solvent evaporation time attributed from the higher boiling-point of toluene and chlorobenzene prefers to induce the"edge-on"orientation of P3HT,whereas the"face-on"orientation exists in the film spin-coated from carbon disulfide and chloroform with lower boiling-points.
Poly(3-hexylthiophene)(P3HT)used in organic field effect transistors,polymer solar cells and so on has received continuous attentions.The conformation of individual chains and the degree of theπ-πstacking are considered to be the important factors to determine the device performance.As the solutionprocessing material,there is no doubt that the solvent properties such as solubility and boiling-point affect the structures of P3HT solid film.However,there is no consistent conclusion that which factor makes the main contribution.In this work,by using Fluorescence correlation spectroscopy,UV-Vis spectroscopy,and reflection-absorption infrared spectroscopy,the effect of the solvent properties on the P3HT lamellar structure in the solid film is investigated.Four different solvents,carbon disulfide,chloroform,toluene and chlorobenzene,were employed.P3HT molecules show more extended conformation in the good solvents of carbon disulfide and chlorobenzene,which show higher solubility to P3HT,compared to the poor solvents of toluene and chloroform.However,in the solid state,the solvent boiling-point plays the important role in the lamellar structure.Firstly,the better backbone planarity comes from the film deposited from the solution in which the solvent has higher boiling-point.Furthermore,theπ-πinteraction between adjacent molecular chains is also improved with the increasing of solvent boiling-point.Besides,the molecular orientation is also affected by the solvent boiling-point.The prolonged solvent evaporation time attributed from the higher boiling-point of toluene and chlorobenzene prefers to induce the"edge-on"orientation of P3HT,whereas the"face-on"orientation exists in the film spin-coated from carbon disulfide and chloroform with lower boiling-points.
引文
[1]佟拉嘎,王锦艳,蹇锡高,等.烷基取代聚噻吩的化学合成与光电性能研究进展[J].功能高分子学报,2004,17(3):535-541.
[2]ZHANG T,YUAN Y,CUI X,et al.Impact of side-chain length on the phase structures of P3ATs and P3AT:PCBMfilms as revealed by SSNMR and FTIR[J].Journal of Polymer Science Part B:Polymer Physics,2018,56(14):751-761.
[3]YANG H,SHIN T,YANG L,et al.Effect of mesoscale crystalline structure on the field-effect mobility of regioregular poly(3-hexyl thiophene)in thin-film transistors[J].Advanced Functional Materials,2005,15(4):671-676.
[4]GOFFRI S,MULLER C,STINGELIN-STUTZMANN N,et al.Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold[J].Nature Materials,2006,5(12):950-956.
[5]KIM J Y,LEE K,COATES N E,et al.Efficient tandem polymer solar cells fabricated by all-solution processing[J].Science,2007,317(5835):222-225.
[6]SIRRINGHAUS H,BROWN P J,FRIEND R H.Two-dimensional charge transport in self-organized,high-mobility conjugated polymers[J].Nature,1999,401(6754):685-688.
[7]PROSA T J,WINOKUR M J.Evidence of a novel side chain structure in regioregular poly(3-alkylthiophenes)[J].Macromolecules,1996,29(10):3654-3656.
[8]STREET R A,NORTHRUP J E,SALLEO A.Transport in polycrystalline polymer thin-film transistors[J].Physical Review B,2005,71(16):165202.
[9]HEFFNER G W,PEARSON D S.Molecular characterization of poly(3-hexylthiophene)[J].Macromolecules,1991,24(23):6295-6299.
[10]KIRIY N,JAHNE E,ADLER H J,et al.One-dimensional aggregation of regioregular polyalkylthiophenes[J].Nano Letters,2003,3(6):707-712.
[11]SCHARSICH C,LOHWASSER R H,SOMMER M,et al.Control of aggregate formation in poly(3-hexylthiophene)by solvent,molecular weight,and synthetic method[J].Journal of Polymer Science Part B:Polymer Physics,2012,50(6):442-453.
[12]YAMAMOTO T,KOMARUDIN D,ARAI M,et al.Extensive studies onπ-stacking of poly(3-alkylthiophene-2,5-diyl)s and poly(4-alkylthiazole-2,5-diyl)s by optical spectroscopy,NMR analysis,light scattering analysis,and X-ray crystallography[J].Journal of the American Chemistry Society,1998,120(9):2047-2058.
[13]BAO Z,DODABALAPUR A,LOVINGER A J.Soluble and processable regioregular poly(3-hexylthiophene)for thin film field-effect transistor applications with high mobility[J].Applied Physics Letters,1996,69(26):4108-4110.
[14]SCHWARTZ B J.Conjugated polymers as molecular materials:How chain conformation and film morphology influence energy transfer and interchain interactions[J].Annual Review of Physical Chemistry,2003,54:141-172.
[15]LEE S,LEE J Y,LEE H.Solvent effects on the characteristics of conductive and luminescent polymers[J].Synthetic Metals,1999,101(1/3):248-249.
[16]KHAN A L T,BANACH M J,KOHLER A.Control ofβ-phase formation in polyfluorene thin films via Franck-Condon analysis[J].Synthetic Metals,2003,139(3):905-907.
[17]HO P K H,CHUA L L,DIPANKAR M,et al.Solvent effects on chain orientation and interchainπ-interaction in conjugated polymer thin films:Direct measurements of the air and substrate interfaces by near-edge X-ray absorption spectroscopy[J].Advanced Materials,2007,19(2):215-221.
[18]CHANG J,SUN B,BREIBY D W,et al.Enhanced mobility of poly(3-hexylthiophene)transistors by spin-coating from high-boiling-point solvents[J].Chemical Materials,2004,16(23):4772-4776.
[19]KLINE R J,MCGEHEE M D,TONEY M F.Highly oriented crystals at the buried interface in polythiophene thin-film transistors[J].Nature Materials,2006,5(3):222-228.
[20]PORZIO W,SCAVIA G,BARBA L,et al.Depth-resolved molecular structure and orientation of polymer thin films by synchrotron X-ray diffraction[J].European Polymer Journal,2011,47(3):273-283.
[21]KLINE R J,MCGEHEE M D,KADNIKOVA E N,et al.Dependence of regioregular poly(3-hexylthiophene)film morphology and field-effect mobility on molecular weight[J].Macromolecules,2005,38(8):3312-3319.
[22]CHO S,LEE K,YUEN J,et al.Thermal annealing-induced enhancement of the field-effect mobility of regioregular poly(3-hexylthiophene)films[J].Journal of Applied Physics,2006,100(11):114503.
[23]SALAMMAL S T,MIKAYELYAN E,GRIGORIAN S,et al.Impact of thermal annealing on the semicrystalline nanomorphology of spin-coated thin films of regioregular poly(3-alkylthiophene)s as observed by high-resolution transmission electron microscopy and grazing incidence X-ray diffraction[J].Macromolecules,2012,45(13):5575-5585.
[24]WANG D,YORDANOV S,PAROOR H M,et al.Probing diffusion of single nanoparticles at water-oil interfaces[J].Small,2011,7(24):3502-3507.
[25]KUMAR P,MEHTA A,MAHURIN S M,et al.Formation of oriented nanostructures from single molecules of conjugated polymers in microdroplets of solution:The role of solvent[J].Macromolecules,2004,37(16):6132-6140.
[26]RIGLER R,ELSON E.Fluorescence Correlation Spectroscopy:Theory and Applications[M].Germany:Springer Verlag,2001:75-81.
[27]CHERDHIRANKORN T,BEST A,KOYNOV K,et al.Diffusion in polymer systems studied by fluorescence correlation spectroscopy[J].Journal of Physical Chemistry B,2009,113(11):3355-3359.
[28]CHEN S A,NI J M.Structure/properties of conjugated conductive polymers:1.Neutral poly(3-alkythiophene)s[J].Macromolecules,1992,25(23):6081-6089.
[29]YANG C,ORFINO F P,HOLDCROFT S.A phenomenological model for predicting thermochromism of regioregular and nonregioregular poly(3-alkylthiophenes)[J].Macromolecules,1996,29(20):6510-6517.
[30]BROWN P J,THOMAS D S,KOHLER A,et al.Effect of interchain interactions on the absorption and emission of poly(3-hexylthiophene)[J].Physical Review B,2003,67(6):064203.
[31]ZHAO K,XUE L,LIU J,et al.A new method to improve poly(3-hexyl thiophene)(P3HT)crystalline behavior:Decreasing chains entanglement to promote order-disorder transformation in solution[J].Langmuir,2010,26(1):471-477.
[32]SCHARSICH C,LOHWASSER R H,SOMMER M,et al.Control of aggregate formation in poly(3-hexylthiophene)by solvent,molecular weight,and synthetic method[J].Journal of Polymer Science Part B:Polymer Physics,2012,50(6):442-453.
[33]SCHERF U,LIST E J W.Semiconducting polyfluorenes-towards reliable structure-property relationships[J].Advanced Materials,2002,14(7):477-487.
[34]MCCULLOCH I,HEENEY M,BAILEY C,et al.Liquid-crystalline semiconducting polymers with high charge-carrier mobility[J].Nature Materials,2006,5(4):328-333.
[35]WU Y,LIU P,ONG B S,et al.Controlled orientation of liquid-crystalline polythiophene semiconductors for highperformance organic thin-film transistors[J].Applied Physical Letters,2005,86(14):142102.
[36]LI G,SHROTRIVA V,HUANG J,et al.High-efficiency solution processable polymer photovoltaic cells by selforganization of polymer blends[J].Nature Materials,2005,4(11):864-868.
[37]FRANCIS S A,ELLISON A H J.Infrared spectra of monolayers on metal mirrors[J].Journal of Optical Society of America,1959,49(2):131-137.
[38]ZHANG J,ZHANG D,SHEN D.Orientation study of atactic poly(methyl methacrylate)thin film by SERS and RAIRspectra[J].Macromolecules,2002,35(13):5140-5144.
[39]ZHANG Y,MUKOYAMA S,HU Y,et al.Thermal behavior and molecular orientation of poly(ethylene 2,6-naphthalate)in thin films[J].Macromolecules,2007,40(11):4009-4015.
[40]DONG H,LI H,WANG E,et al.Molecular orientation and field-effect transistors of a rigid rod conjugated polymer thin films[J].Journal of Physical Chemistry B,2009,113(13):4176-4180.
[41]CURTIS M D,NANOS J I,MOON H,et al.Side chain disorder and phase transitions in alkyl-substituted,conjugated oligomers:Relation to side-chain melting in P3ATs[J].Journal of American Chemistry Society,2007,129(48):15072-15084.
[42]WANG X,YUAN Y,HAN L,et al.Effect of solvent annealing temperature on crystal modifications and phase transition behavior of regioregular poly(3-octylthiophene)[J].Chinese Journal of Polymer Science,2014,32(9):1158-1166.
[43]YUAN Y,ZHANG Y,CUI X,et al.Rotation-assisted formation of poly(3-butylthiophene)nanowires:Morphology,microstructure,and electrical property[J].Journal of Polymer Science Part B:Polymer Physics,2018,56(14):1027-1034.
[2]ZHANG T,YUAN Y,CUI X,et al.Impact of side-chain length on the phase structures of P3ATs and P3AT:PCBMfilms as revealed by SSNMR and FTIR[J].Journal of Polymer Science Part B:Polymer Physics,2018,56(14):751-761.
[3]YANG H,SHIN T,YANG L,et al.Effect of mesoscale crystalline structure on the field-effect mobility of regioregular poly(3-hexyl thiophene)in thin-film transistors[J].Advanced Functional Materials,2005,15(4):671-676.
[4]GOFFRI S,MULLER C,STINGELIN-STUTZMANN N,et al.Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold[J].Nature Materials,2006,5(12):950-956.
[5]KIM J Y,LEE K,COATES N E,et al.Efficient tandem polymer solar cells fabricated by all-solution processing[J].Science,2007,317(5835):222-225.
[6]SIRRINGHAUS H,BROWN P J,FRIEND R H.Two-dimensional charge transport in self-organized,high-mobility conjugated polymers[J].Nature,1999,401(6754):685-688.
[7]PROSA T J,WINOKUR M J.Evidence of a novel side chain structure in regioregular poly(3-alkylthiophenes)[J].Macromolecules,1996,29(10):3654-3656.
[8]STREET R A,NORTHRUP J E,SALLEO A.Transport in polycrystalline polymer thin-film transistors[J].Physical Review B,2005,71(16):165202.
[9]HEFFNER G W,PEARSON D S.Molecular characterization of poly(3-hexylthiophene)[J].Macromolecules,1991,24(23):6295-6299.
[10]KIRIY N,JAHNE E,ADLER H J,et al.One-dimensional aggregation of regioregular polyalkylthiophenes[J].Nano Letters,2003,3(6):707-712.
[11]SCHARSICH C,LOHWASSER R H,SOMMER M,et al.Control of aggregate formation in poly(3-hexylthiophene)by solvent,molecular weight,and synthetic method[J].Journal of Polymer Science Part B:Polymer Physics,2012,50(6):442-453.
[12]YAMAMOTO T,KOMARUDIN D,ARAI M,et al.Extensive studies onπ-stacking of poly(3-alkylthiophene-2,5-diyl)s and poly(4-alkylthiazole-2,5-diyl)s by optical spectroscopy,NMR analysis,light scattering analysis,and X-ray crystallography[J].Journal of the American Chemistry Society,1998,120(9):2047-2058.
[13]BAO Z,DODABALAPUR A,LOVINGER A J.Soluble and processable regioregular poly(3-hexylthiophene)for thin film field-effect transistor applications with high mobility[J].Applied Physics Letters,1996,69(26):4108-4110.
[14]SCHWARTZ B J.Conjugated polymers as molecular materials:How chain conformation and film morphology influence energy transfer and interchain interactions[J].Annual Review of Physical Chemistry,2003,54:141-172.
[15]LEE S,LEE J Y,LEE H.Solvent effects on the characteristics of conductive and luminescent polymers[J].Synthetic Metals,1999,101(1/3):248-249.
[16]KHAN A L T,BANACH M J,KOHLER A.Control ofβ-phase formation in polyfluorene thin films via Franck-Condon analysis[J].Synthetic Metals,2003,139(3):905-907.
[17]HO P K H,CHUA L L,DIPANKAR M,et al.Solvent effects on chain orientation and interchainπ-interaction in conjugated polymer thin films:Direct measurements of the air and substrate interfaces by near-edge X-ray absorption spectroscopy[J].Advanced Materials,2007,19(2):215-221.
[18]CHANG J,SUN B,BREIBY D W,et al.Enhanced mobility of poly(3-hexylthiophene)transistors by spin-coating from high-boiling-point solvents[J].Chemical Materials,2004,16(23):4772-4776.
[19]KLINE R J,MCGEHEE M D,TONEY M F.Highly oriented crystals at the buried interface in polythiophene thin-film transistors[J].Nature Materials,2006,5(3):222-228.
[20]PORZIO W,SCAVIA G,BARBA L,et al.Depth-resolved molecular structure and orientation of polymer thin films by synchrotron X-ray diffraction[J].European Polymer Journal,2011,47(3):273-283.
[21]KLINE R J,MCGEHEE M D,KADNIKOVA E N,et al.Dependence of regioregular poly(3-hexylthiophene)film morphology and field-effect mobility on molecular weight[J].Macromolecules,2005,38(8):3312-3319.
[22]CHO S,LEE K,YUEN J,et al.Thermal annealing-induced enhancement of the field-effect mobility of regioregular poly(3-hexylthiophene)films[J].Journal of Applied Physics,2006,100(11):114503.
[23]SALAMMAL S T,MIKAYELYAN E,GRIGORIAN S,et al.Impact of thermal annealing on the semicrystalline nanomorphology of spin-coated thin films of regioregular poly(3-alkylthiophene)s as observed by high-resolution transmission electron microscopy and grazing incidence X-ray diffraction[J].Macromolecules,2012,45(13):5575-5585.
[24]WANG D,YORDANOV S,PAROOR H M,et al.Probing diffusion of single nanoparticles at water-oil interfaces[J].Small,2011,7(24):3502-3507.
[25]KUMAR P,MEHTA A,MAHURIN S M,et al.Formation of oriented nanostructures from single molecules of conjugated polymers in microdroplets of solution:The role of solvent[J].Macromolecules,2004,37(16):6132-6140.
[26]RIGLER R,ELSON E.Fluorescence Correlation Spectroscopy:Theory and Applications[M].Germany:Springer Verlag,2001:75-81.
[27]CHERDHIRANKORN T,BEST A,KOYNOV K,et al.Diffusion in polymer systems studied by fluorescence correlation spectroscopy[J].Journal of Physical Chemistry B,2009,113(11):3355-3359.
[28]CHEN S A,NI J M.Structure/properties of conjugated conductive polymers:1.Neutral poly(3-alkythiophene)s[J].Macromolecules,1992,25(23):6081-6089.
[29]YANG C,ORFINO F P,HOLDCROFT S.A phenomenological model for predicting thermochromism of regioregular and nonregioregular poly(3-alkylthiophenes)[J].Macromolecules,1996,29(20):6510-6517.
[30]BROWN P J,THOMAS D S,KOHLER A,et al.Effect of interchain interactions on the absorption and emission of poly(3-hexylthiophene)[J].Physical Review B,2003,67(6):064203.
[31]ZHAO K,XUE L,LIU J,et al.A new method to improve poly(3-hexyl thiophene)(P3HT)crystalline behavior:Decreasing chains entanglement to promote order-disorder transformation in solution[J].Langmuir,2010,26(1):471-477.
[32]SCHARSICH C,LOHWASSER R H,SOMMER M,et al.Control of aggregate formation in poly(3-hexylthiophene)by solvent,molecular weight,and synthetic method[J].Journal of Polymer Science Part B:Polymer Physics,2012,50(6):442-453.
[33]SCHERF U,LIST E J W.Semiconducting polyfluorenes-towards reliable structure-property relationships[J].Advanced Materials,2002,14(7):477-487.
[34]MCCULLOCH I,HEENEY M,BAILEY C,et al.Liquid-crystalline semiconducting polymers with high charge-carrier mobility[J].Nature Materials,2006,5(4):328-333.
[35]WU Y,LIU P,ONG B S,et al.Controlled orientation of liquid-crystalline polythiophene semiconductors for highperformance organic thin-film transistors[J].Applied Physical Letters,2005,86(14):142102.
[36]LI G,SHROTRIVA V,HUANG J,et al.High-efficiency solution processable polymer photovoltaic cells by selforganization of polymer blends[J].Nature Materials,2005,4(11):864-868.
[37]FRANCIS S A,ELLISON A H J.Infrared spectra of monolayers on metal mirrors[J].Journal of Optical Society of America,1959,49(2):131-137.
[38]ZHANG J,ZHANG D,SHEN D.Orientation study of atactic poly(methyl methacrylate)thin film by SERS and RAIRspectra[J].Macromolecules,2002,35(13):5140-5144.
[39]ZHANG Y,MUKOYAMA S,HU Y,et al.Thermal behavior and molecular orientation of poly(ethylene 2,6-naphthalate)in thin films[J].Macromolecules,2007,40(11):4009-4015.
[40]DONG H,LI H,WANG E,et al.Molecular orientation and field-effect transistors of a rigid rod conjugated polymer thin films[J].Journal of Physical Chemistry B,2009,113(13):4176-4180.
[41]CURTIS M D,NANOS J I,MOON H,et al.Side chain disorder and phase transitions in alkyl-substituted,conjugated oligomers:Relation to side-chain melting in P3ATs[J].Journal of American Chemistry Society,2007,129(48):15072-15084.
[42]WANG X,YUAN Y,HAN L,et al.Effect of solvent annealing temperature on crystal modifications and phase transition behavior of regioregular poly(3-octylthiophene)[J].Chinese Journal of Polymer Science,2014,32(9):1158-1166.
[43]YUAN Y,ZHANG Y,CUI X,et al.Rotation-assisted formation of poly(3-butylthiophene)nanowires:Morphology,microstructure,and electrical property[J].Journal of Polymer Science Part B:Polymer Physics,2018,56(14):1027-1034.