简介：Twoalkylsubstitutedpolythiophenederivatives:poly(3-hexylthiophene)(P3HT)andpoly(3-decylthiophene)(P3DT),havesynthesizedbyoxidationcouplingpolymerizationof3-alkylthiopheneusingiron(III)chlorideascatalystinchloroform.Whilebothpolymersinpurechloroformsolutionhavemaximumabsorptionatapproximatelysamewavelengthof440nm,theybehavedifferentlywithrespecttochangesobservedontheirUV-visibleandphotoluminescencespectrawhenthequalityofthepoorsolventischangedingoodsolvent(chloroform)/poorsolvent(methanol)mixtures.Withincreasingvolumefractionofmethanolinmixtures,theabsorptionspectraofP3HTandP3DTred-shift,peakingatmaximumwavelengthof495nm(P3HT)and510nm(P3DT).Furthermore,theabsorptionspectraofthetwopolymersinchloroformblue-shiftasthetemperaturerises.P3HTshows4.73nmblue-shiftsat50℃incontrasttothecaseat20℃,whileP3DTblue-shiftsabout5.04nm.Thephotoluminescencespectraofthetwopolymersinmixedsolutionarealsoinvestigated,whichshowthattheluminescencespectrashifttolongerwavelengthwithanaccompanyingdropinthePLintensityasmethanolisincreased.Theabsorptionandemissionspectraofthetwopolymersinapoorsolventandathinfilmaresimilar,whichindicatethatasimilarlongerconjugationlengthinthetwocases.Itcouldconcludethatthepolymersexistalmostthesameconformationsandaggregationsinbothapoorsolventandathinfilm.P3DTexhibitsmoresensitivespectraproperties(bigred-shiftsinbothabsorptionandluminescencespectrainpoorsolventsandlargeblue-shiftsathightemperature)withcontrasttoP3HT,whichimplythatlongsidealkylmayimprovethechromicpropertiesofthepolymer.