Electrochemical syntheses and self assembly of nanostructure as modified electrodes for polythiophene preparation

ELECTROCHEMICALSYNTHESESAND
SELF-ASSEMBLYOFNANOSTRUCTUREAS
MODIFIEDELECTRODESFORPOLYTHIOPHENE
PREPARATION
ZHANGCHUNYAN
NATIONALUNIVERSITYOFSINGAPORE
2002
ELECTROCHEMICALSYNTHESESAND
SELF-ASSEMBLYOFNANOSTRUCTUREAS
MODIFIEDELECTRODESFORPOLYTHIOPHENE
PREPARATION
ZHANGCHUNYAN
(B.Sc.NanjingUniversityofP.R.China)
ATHESISSUBMITTED
FORDOCTOROFPHILOSOPHY
DEPARTMENTOFCHEMISTRY
NATIONALUNIVERSITYOFSINGAPORE
2002
i
Acknowledgments
Iwouldliketoexpressmygreatestappreciationtomysupervisors,Professor
Hardy,S.O.ChanandAssociateProfessorNgSiuChoonforprovidingthisop-
portunityformyacademicpursuitandfortheirgreathelpandvaluableguidance
throughouttheyears.
MyheartfeltthanksmustgotoallthecolleaguesintheFunctionalPolymer
Laboratory,NUSfortheircontinuoushelpandencouragement.Specialthanksto
Dr.MiaoPingandDr.Richard,SeowSweeHowfortheirkindnessinproviding
bithiophenederivativesformyresearchandtheirvaluableadvice,Dr.Chen
Zhikuan,Dr.DouZeling,HanYanhuiandFuPingfortheirassistanceinlablife,
OngTengTeng,XuLingge,ChenDizhong,SunTong,XuJinmei,LuHongfang,
MaYifei,WongYeongChingandmanyothersfortheirhelpandaccompany.

Iwouldalsoliketothankthesta®ofCentralInstrumentalLab,ChemicalStore
inChemistryDepartmentfortheirassistanceduringthisproject.Manythanks
toPhysicsDepartment,MaterialScienceDepartmentandBiologyDepartment
inusingAFM,SEMandTEMinstruments.SpecialthankstoMr.WongHow
KwongfromPhysicsDepartmentfordoingtheXPSanalysis.
Finally,Iwishtoexpressmygratitudetomyparentsfortheirconstantcaring
ii
andsupportthroughoutmylife.SpecialthanksgotomyhusbandZouYufor
hissupportandhelpinmythesisediting.
ZhangChunyan
2002
iii
Contents
Acknowledgmentsi
Contentsiii
ListofFiguresx
ListofTablesxix
Abbreviationsxxi
Summaryxxiv
Chapter1.Introduction1
1.1IntroductiontoConductingPolymers 1
1.2ConductionMechanism 2
1.2.1BandTheory 3
1.2.2PolaronandBipolaronModel 4
1.2.3ConductivityofConductingPolymers 6
1.3ChemistryofPolythiophenes 7
1.3.1FunctionalizationofPolythiophenes 8
1.3.2ChemicalSynthesesofPolythiophenes 10
1.3.3ElectrochemicalSynthesesofPolythiophenes 10
1.3.4FactorsinElectrochemicalPolymerization 12

1.4PropertiesofPolythiophenes 13
1.4.1ElectrochemicalPropertiesofPolythiophenes 13
iv
1.4.2SpectroscopicPropertiesofPolythiophenes-UV-vis-NIR
Spectroscopy 16
1.4.3ChemicalEnvironmentofElements-X-rayPhotoelectron
Spectroscopy 18
1.5Self-assemblyofPolythiophenes 19
1.6ABridge:ConductingPolymersandMetalNanoparticles 21
1.7AnIntroductiontoMetalNanoparticle 22
1.7.1HistoricPerspectiveofGoldNanoparticles 22
1.7.2BandStructureofNobleMetalNanoparticles 23
1.7.3StabilizationMethodsofMetalNanoparticles 24
1.8PreparativeMethodsofMetalNanoparticles 26
1.8.1SolutionPhaseSaltReduction 26
1.8.2Brust'sMethodandIt'sApplications 27
1.9PropertiesandCharacterizationofMetalNanoparticles 29
1.9.1SolubilityofMetalNanoparticles 31
1.9.2SizeandShapeofNanoparticles 31
1.9.3UV-VisibleSpectroscopy 31
1.9.4X-RayPhotoelectronSpectroscopy(XPS) 34
1.9.5TransmissionElectronMicroscopy(TEM) 35
1.9.6AtomicForceMicroscopy(AFM) 36
1.9.7Electrochemistry:CyclicVoltammetry(CV)andDi®eren-
tialPulseVoltammetry(DPV) 37
1.10ScopeofDissertation 38
Chapter2.ElectrochemicalSynthesesofPolybithiopheneDeriva-
tivesUsingBF
3
¢OEt

2
asElectrolyte41
2.1Introduction 41
2.2Experimental 43
v
2.2.1Monomers 43
2.2.2DeterminationofMonomerOxidationpotential 45
2.2.3DeterminationofPolymerOxidationPotential 45
2.3ResultsandDiscussion 45
2.3.1ElectrochemicallyPolymerizationofMono-substitutedBithio-
phenes 46
2.3.2ElectrochemicalPolymerizationofBithiopheneswithAl-
ternateElectron-donatingandElectron-withdrawingGroups53
2.3.3ElectrochemicallyPolymerizationofSymmetricallyDi-substituted
Bithiophenes 56
2.4Summary 64
Chapter3.PropertiesofBF
3
¢OEt
2
DopedPolybithiopheneDeriv-
atives66
3.1Introduction 66
3.2Experimental 67
3.2.1PreparationofPolymers 67
3.2.2Ultraviolet-visibleAbsorptionSpectroscopy 67
3.2.3X-rayPhotoelectronSpectroscopy 68
3.3ResultsandDiscussion 68
3.3.1ElectrochemicalAnalysisofPolymers 68
3.3.2ElectrolyteintheElectrochemicalSynthesesandElectro-

chemicalPropertiesofHalogenSymmetricallyDisubstituted
Polybithiophenes 80
3.3.3OpticalPropertiesofResultingPolymers 82
3.3.4XPSStudyofPolymersPreparedfromBF
3
¢OEt
2
88
3.4Summary 94
vi
Chapter4.ThienylthiolateModi¯edPolycrystallineAuElectrode
forElectrochemicalPolymerizationofSubstitutedBithiophenes95
4.1Introduction 95
4.2Experimental 97
4.2.1Self-AssembledThienylthiolateMonolayeronPolycrystalline
AuElectrode 97
4.2.2ElectrochemicalPolymerizationonModi¯edElectrode 98
4.3ResultsandDiscussions 99
4.3.1FormationofSelf-AssembledThienylthiolateMonolayeron
AuElectrode 99
4.3.2MonolayerCharacterizationbyXPS 100
4.3.3CyclicVoltammetryofFerrocyanideonChemisorbedMono-
layerModi¯edAuElectrode 102
4.3.4AtomicForceMicroscopyofChemisorbedMonolayer 103
4.3.5ElectrochemicalPolymerizationofBithiophenesonThienylth-
iolateMonolayerModi¯edAuElectrode 105
4.3.6CVofPolymer-coatedElectrodeRinsedbyOrganicSolvent109
4.4Summary 113
Chapter5.MicroelectrodeofSelf-AssembledAqueousAuNanopar-
ticlesonITOGlassforElectrochemicalPolymerizationofBithio-

phene114
5.1Introduction 114
5.2Experimental 115
5.3ResultsandDiscussion 116
5.3.1Self-assemblyofAqueousAuNanoparticlesonSilanized
ITOGlassElectrode 116
vii
5.3.2ElectrochemistryofVariousModi¯edElectrodes 117
5.3.3UV-visSpectroscopyinCharacterizationofSurfaceModi-
¯cation 119
5.3.4SurfaceMorphologyofModi¯edSurfaces 121
5.3.5XPSStudyinModi¯edSurfaces 124
5.3.6ElectrochemistryofPBTSynthesizedonVariousElectrodes126
5.3.7SpectroscopicPropertiesofPBTSynthesizedonVarious
Electrodes 127
5.3.8XPSstudyinPBTPreparedonModi¯edElectrode 128
5.4Summary 131
Chapter6.ThienylthiolatesMonolayerProtectedGoldNanopar-
ticles132
6.1Introduction 132
6.2Experimental 133
6.2.1SynthesesofThienylthiolatesasStabilizationLigands 133
6.2.2PreparationofGoldNanoparticleswithStabilizationLigands134
6.3ResultsandDiscussions 135
6.3.1MonolayerProtectedGoldNanoparticle 135
6.3.2Solubility 138
6.3.3ParticleSizeandDistribution 138
6.3.4Composition 144
6.3.5SpectroscopicProperties 148
6.4Summary 151

Chapter7.CoulombStaircaseFeatureofThienylthiolate-Stabilized
AuNanoparticles152
7.1Introduction 152
7.1.1Background 152
viii
7.1.2MetalNanoparticlesasBuildingBlocks 153
7.1.3CoulombStaircase 153
7.1.4SolutionEnsembleCoulombStaircase 156
7.2Experimental 158
7.3ResultsandDiscussions 159
7.3.1CVandDPVofThienylthiolateStabilizedGoldNanopar-
ticles 159
7.3.2SolventE®ectinQuantizedDoubleLayerCharging 162
7.4Summary 165
Chapter8.ElectrochemicalPolymerizationofBithiophenesIncor-
poratingThienylthiolateStabilizedAuNanoparticles166
8.1Introduction 166
8.2Experimental 167
8.3ResultsandDiscussions 168
8.3.1Self-assemblyofNonaqueousAuColloidonsilanizedITO
GlassElectrode 168
8.3.2ElectrochemicalPolymerizationofBithiophenesinaSolu-
tionContainingThienylthiolateStabilizedAuNanoparticles175
8.3.3PropertiesofPolybithiophenesIncorporatedwithAuNanopar-
ticles 177
8.4Summary 183
Chapter9.ConclusionandFutureWork185
9.1Conclusion 185
9.2ScopeforFutureWork 186
Chapter10.ExperimentalSection188

10.1Instrumentation 188
ix
10.2Chemicals 191
10.3Syntheses 191
10.3.1PreparationofThienylThiols 191
10.3.2ElectrochemicalPolymerization 194
10.3.3PreparationofColloidalGoldNanoparticles 194
10.3.4ElectrodeModi¯cation 195
Bibliography197
x
ListofFigures
1.1Illustrationofenergybandstructuresofmaterials.VB:valence
band,CB:conductionband 3
1.2Polaronandbipolaronstructuresofpolythiophene 5
1.3Aromaticandquinoidstructuresofthiophene 5
1.4Formationofmid-gapstatesofpolaronorbipolaronuponp-doping.6
1.5Structuresof3or4positionfunctionalizedoligothiophenes 8
1.6Structuresofthiopheneswithconjugatedspacer 9
1.7Structuresofthiopheneswithfusedringfunctionalization 9
1.8Structureofsymmetricallydisubstitutedoligothiophene 10
1.9Reactionmechanismofanodicpolymerizationofthiophene 12
1.10CVofp-dopeofPBRHEBTin0.1Mmonomerfree(A)Bu
4
NBF
4
/CH
3
CN
and(B)BF
3

¢OEt
2
,scanrate:50mVs
¡1
14
1.11Illustrationofenergybandstructuretransitionbetweenbulkmetal
andmolecularclusters 24
1.12Electrostaticstabilizationofmetalcolloidparticles 25
1.13Stericstabilizationofmetalcolloidparticlesbypolymersorsur-
factantmolecules 26
xi
1.14ExamplesofthiolligandsusedtoprepareMPCs:(a)straight
chainalkanethiols;(b)glutanthione;(c)tiopronin;(d)thiolated
poly(tethyleneglycol);(e)p-mercaptophenol;(f)aromaticalka-
nethiol;(g)phenylalkanethiols;(h)(°-mercaptopropyl)-trimethoxysilane.30
1.15SketchofDOSforAu:(A)bulkAu;(B)verylargeAuclusters;
(C)verysmallAuclusters 32
1.16UV-Visspectrumofasampleof » 13nmAunanoparticlespre-
paredfromcitratereductioninourlab 34
1.17(A)HeightAFMimageand(B)TEMimageof3-mercapto-2,2'-
bithiophenestabilizedgoldnanoparticles(preparedinourlab) 37
2.1Mono-substituted2,2'-bithiophenes 44
2.2Dissymmetricallydisubstituted2,2'-bithiophenes 44
2.3Symmetricallydisubstituted2,2'-bithiophenes 44
2.4Polymerizationof3OCBTinBu
4
NBF
4
/CH
3

CN.0.05Mmonomer,
scanrate:50mVs
¡1
47
2.5Polymerizationof(a)3OMEBTand(b)3BRBTinBF
3
¢OEt
2
.0.05
Mmonomer,scanrate:50mVs
¡1
51
2.6Polymerizationof0.05M(a)BT,(b)3OMEBT,(c)3OCBTand
(d)3BRBTbyCEmethodsat0.2mAcm
¡2
inBF
3
¢OEt
2
52
2.7Polymerizationof0.05MBRHEBTbyCEmethodsat0.2mA
cm
¡2
in(a)BF
3
¢OEt
2
and(b)Bu
4
NBF

4
/CH
3
CN 54
2.8PolymerizationofBRHEBTin(A)BF
3
¢OEt
2
and(B)Bu
4
NBF
4
/CH
3
CN.
0.05Mmonomer,scanrate:50mVs
¡1
55
xii
2.9Polymerizationof(A)DBRBTand(B)DIBTinBF
3
¢OEt
2
,0.01-
0.05Mmonomer,scanrate:50mVs
¡1
58
2.10Polymerizationof(a)DCLBT,(b)DBRBTand(c)DIBTbyCE
methodsat0.1mAcm
¡2

inBF
3
¢OEt
2
,0.01-0.05Mmonomer 60
2.11Polymerizationof(a)DOCBT,(b)DSOCBTand(c)DOBUBT
inBF
3
¢OEt
2
,0.05Mmonomer,scanrate:50mVs
¡1
62
2.12Polymerizationof0.05M(a)DOCBT,(b)DSOCBTand(c)DOBUBT
byCEmethodsat0.2mAcm
¡2
inBF
3
¢Et
2
64
3.1CVofp-dopeof(a)P3OCBTand(b)P3OMEBTad(c)P3BRBT
inmonomerfreeBF
3
¢OEt
2
,scanrate:50mVs
¡1
71
3.2The¯rst10CVcyclesof(a)P3OCBTand(b)P3OMEBTand(c)

P3BRBTinmonomerfreeBF
3
¢OEt
2
,scanrate:50mVs
¡1
73
3.3CVofp-dopeofPBRHEBTinmonomerfree(A)BF
3
¢OEt
2
and
(B)0.1MBu
4
NBF
4
/CH
3
CN,scanrate:50mVs
¡1
74
3.4CVofn-dopeofPBRHEBT(preparedfromBu
4
NBF
4
/CH
3
CN)in
0.1MmonomerfreeBu
4

NBF
4
/CH
3
CN,scanrate:50mVs
¡1
75
3.5CVofp-andn-dopeofPBRHEBTin0.1MmonomerfreeBu
4
NBF
4
/CH
3
CN,
scanrate:50mVs
¡1
76
3.6CVofp-dopeof(A)PDCLBT,(B)PDBRBTand(C)PDIBTin
monomerfreeBF
3
¢OEt
2
,scanrate:50mVs
¡1
78
3.7CVofp-dopeof(a)PDOCBTand(b)PDSOCBTinmonomer
freeBF
3
¢OEt
2

,scanrate:50mVs
¡1
79
xiii
3.8CVofp-dopeofPDBRBTprepared(a)fromBF
3
¢OEt
2
inmonomer
freeBF
3
¢OEt
2
,(b)from0.05MBu
4
NBF
4
/CH
3
CNin0.1Mmonomer
freeBu
4
NBF
4
/CH
3
CNand(c)from0.05MBu
4
NBF
4

/CH
3
CNin
monomerfreeBF
3
¢OEt
2
,scanrate:50mVs
¡1
81
3.9CVofp-dopeofPDIBTprepared(a)fromBF
3
¢OEt
2
inmonomer
freeBF
3
¢OEt
2
and(c)from0.05MBu
4
NBF
4
/CH
3
CNinmonomer
freeBF
3
¢OEt
2

,scanrate:50mVs
¡1
82
3.10UV-vis-NIRspectraof(A)PBT,(B)P3OCBT,(C)P3OMEBT
and(D)P3BRBTin(a)dedopedand(b)dopedstateinBF
3
¢OEt
2
.85
3.11UV-vis-NIRspectraof(A)PDCLBT,(B)PDBRBTand(C)PDIBT
in(a)dedopedand(b)dopedstatebyBF
3
¢OEt
2
87
3.12XPSspectraofC(1s)andS(2p)of(A)BF
3
dopedPBT,(B)de-
dopedPBTpreparedfromelectrosynthesisinBF
3
¢OEt
2
90
3.13XPSspectraofC(1s)andS(2p)of(A)BF
¡
4
dopedPBT,(B)de-
dopedPBTpreparedfromelectrosynthesisinBu
4
NBF

4
/CH
3
CN.91
3.14XPSspectraofF(1s)of(A)BF
3
dopedPBT,(B)BF
¡
4
dopedPBT,
(C)dedopedPBTpreparedinBF
3
¢OEt
2
and(D)BF
3
redoped
PBTpreparedinBu
4
NBF
4
/CH
3
CN 93
4.1Structureof5SHBTandmonomersforelectrochemicalpolymer-
ization 98
4.2Schematicillustrationofsurfaceorientationof5SHBTmonolayer
onAuelectrode 99
4.3S(2p)andAu(4f)spectraof5SHBTmonolayeronAuelectrode 101
xiv

4.4Voltametricresponseof5.0mMFe(CN)
4+
6
in0.5MNa
2
SO
4
aque-
oussolutionon(a)bareAuelectrode,5SBTmonolayercovered
Auelectrodefor(b)¯rstand(c)50thatscanrateof50mVs
¡1
103
4.53DheightAFMimagesof(A)5SHBTmonolayermodi¯edand(B)
baregoldmirrorsurface 104
4.62DphaseAFMimagesof(A)5SHBTmonolayermodi¯edand(B)
baregoldmirrorsurface 105
4.7CEforpolymerizationof3OCTonthe(a)5SHBTmodi¯edand
(b)unmodi¯edAuelectrodesurfacein0.05MBu
4
NBF
4
/CH
3
CN.106
4.8CEforpolymerizationofBTonthe(a)5SHBTmodi¯edand(b)
unmodi¯edAuelectrodesurfacein0.05MBu
4
NBF
4
/CH

3
CN 107
4.9CEforpolymerizationofDOBUBTonthe(a)5SHBTmodi¯ed
and(b)unmodi¯edAuelectrodesurfacein0.05MBu
4
NBF
4
/CH
3
CN.108
4.10CEforpolymerizationofDSOCBTonthe(a)5SHBTmodi¯edand
(b)unmodi¯edAuelectrodesurfacein0.05MBu
4
NBF
4
/CH
3
CN.109
4.11CEforpolymerizationofDBRBTonthe(a)5SHBTmodi¯edand
(b)unmodi¯edAuelectrodesurfacein0.05MBu
4
NBF
4
/CH
3
CN.110
4.12CyclicVoltammetryofPBTdepositedon(a)5SBTmonolayer
coveredAuelectrode,(b)bareAuelectrodeafterrinsinginTHF
in0.1MBu
4

NBF
4
/CH
3
CNatscanrateof50mVs
¡1
111
4.13CyclicVoltammetryofPDBRBTdepositedon(a)5SBTmono-
layercoveredAuelectrode,(b)bareAuelectrodeafterrinsingin
THFin0.1MBu
4
NBF
4
/CH
3
CNatscanrateof50mVs
¡1
112
xv
5.1Schematicdiagramofself-assembledAunanoparticlesontosilanized
ITOglasselectrodeandsubsequentself-assemblyof5SHBTmole-
cules(A: !-aminopropyl-triethoylsilane;B:5SHBT) 117
5.2Voltametricresponseof5.0mMFe(CN)
4+
6
in0.5MNa
2
SO
4
aque-

oussolutionon(a)ITO,(b)ITOSAand(c)ITOSASBTatscan
rateof50mVs
¡1
118
5.3CVof(a)ITO,(b)ITOSAand(c)ITOSASBTin0.1MBu
4
NBF
4
/CH
3
CN
atscanrateof50mVs
¡1
.Insertedisthatofpolycrystallinegold
electrode 119
5.4UV-visspectraofaqueousgoldnanoparticlesadsorbedonsilanized
ITOglasselectrodebydi®erentimmersiontime 120
5.5UV-visabsorbanceofaqueousgoldnanoparticlesadsorbedonsilanized
ITOglasselectrodeindi®erentdippingtimeframe 121
5.62DheightAFMimagesof(A)ITO,(B)ITOS,(C)ITOSAand
(D)ITOSASBTsurfaces 122
5.72DphaseAFMimagesof(A)ITO,(B)ITOS,(C)ITOSAand(D)
ITOSASBTsurfaces 123
5.8S(2p)spectrumofITOSASBTsurfaces 124
5.9Au(4f)spectraof(A)ITOSAand(B)ITOSASBTsurfaces 125
5.10CVsofPBTdepositedon(a)ITO,(b)ITOSAand(c)ITOSASBT
in0.1MBu
4
NBF
4

/CH
3
CNatscanrateof50mVs
¡1
127
5.11UV-visspectraofPBTdepositedon(a)ITO,(b)ITOSAand(c)
ITOSASBTin0.1MBu
4
NBF
4
/CH
3
CN 128
5.12C(1s),S(2p)andAu(4f)spectraofPBTobtainedon(A)ITOSA
and(B)ITOSASBTsurfaces 130
xvi
6.1Structuresofthienylthiolatecompounds 134
6.2Schematicillustrationofthienylthiolatemonolayerprotectedgold
nanoparticle 137
6.3(A)TEMand(B)AFMheightimagesofAUSSBTnanoparticles.140
6.4(A)TEMand(B)AFMheightimagesofAURSBTnanoparticles.141
6.5(A)TEMand(B)AFMheightimagesofAU5SBTnanoparticles.142
6.6(A)TEMand(B)AFMheightimagesofAU3SBTnanoparticles.142
6.7TEMImagesofAUBRSBTnanoparticleswithasurfactant-metal
feedingratioof(A)1:1,(b)1:2,(C)2:1and(D)5:1 143
6.8XPSspectraofC(1s),Au(4f)andS(2p)ofAUBRSBTcastingon
ITOglass 146
6.9Au(4f)spectraof(A)AU3SBT,(B)AU5SBT,(C)AURSBTand
(D)AUSSBT 147
6.10UVspectraof(a)AU3SBT,(b)AURSBT,(c)AU5SBT,(d)AUSSBT

and(e)AUBRSBTintoluenesolution 149
6.11UVspectraofAUBRSBTpreparedwith(a)2:1,(b)1:1,(c)1:2
and(d)1:5BRSHBTtogoldmoleratio 149
6.12UVabsorptionspectraofsolid-stateAUSSBTafterannealingbe-
tween20
±
Cand240
±
C 151
7.1SchematicSTMdoubletunnel-junctionmodel 154
7.2Current(I)inresponsetoanappliedpotentialdi®erence(V
ap
)for
a1DarrayofclustersexhibitingCoulombstaircasebehavior. V
T
isthethresholdvoltagerequiredtoachieveconduction 156
xvii
7.3SchematiceelctrochemcalensemleCoulombstaircasemodel. R
ct
is
charge-transferreistance, C
DL
isdoublelayercapacitanceand Z
W
isdi®usional(Warburg)impedanceforclusterstransportthrough
thesolution 157
7.4CyclicVoltammetryof(A)AU3SBT,(B)AU5SBT,(C)AUSSBT
and(D)AURSBTin0.1moll
¡1
Bu

4
NBF
4
co-solvent(1:1v:v)of
tolueneandPhCN.Three-electrodecellwithPtdiscelectrode(0.5
cm
2
)asworkingelectrode,PtwireascounterelectrodeandSCE
asreferenceelectrode,scanrate:10mVS
¡1
160
7.5Di®erentialPulseVoltammetryof(A)AU3SBT,(B)AU5SBT,(C)
AUSSBTand(D)AURSBTin0.1moll
¡1
Bu
4
NBF
4
co-solvent(1:1
v:v)oftolueneandPhCN.scanrate:10mVS
¡1
,pulseheight:50
mV,pulsewidth:50ms,pulseperiod:500ms 161
7.6CyclicVoltammetryofAUSSBTin0.1moll
¡1
Bu
4
NBF
4
inco-

solvent(1:1v:v)oftolueneand(A)CH
2
Cl
2
,(B)MeCN,(C)PhCN
and(D)PhNO
2
,scanrate:10mVS
¡1
163
7.7Di®erentialPulseVoltammetry(DPV)ofAUSSBTin0.1moll
¡1
Bu
4
NBF
4
inco-solvent(1:1v:v)oftolueneand(A)CH
2
Cl
2
,(B)
MeCN,(C)PhCNand(D)PhNO
2
,scanrate:10mVS
¡1
,pulse
height:50mV,pulsewidth:50ms,pulseperiod:500ms 164
7.8DiagramshowingtheproposedarrangementofSSBTadsorbedon
thesurfaceofgoldcluster 165
xviii

8.1UV-visspectraofnonaqueousgoldnanoparticles(A)AUSSBT,
(B)AURSBT,(C)AU3SBTand(D)Au5SBTadsorbedonsilanized
ITOglasselectrode 169
8.2AFM(A)2Dphaseimageand(B)3Dphaseimageofself-assembled
SSBTstabilizedAunanoparticlesonITOglass 170
8.3SEMimageofself-assembledSSBTstabilizedAunanoparticleson
ITOglass 171
8.4CyclicVoltammetryof(a)SSBTAUmodi¯edITOglasselectrode
and(b)bareITOglasselectrodein0.1MBu
4
NBF
4
/CH
3
CNso-
lution.ScanRate:50mVS
¡1
.Inserted:CVofbareAuelectrode
in0.1MBu
4
NBF
4
/CH
3
CNsolution 173
8.5PBTpreparationbyCVinamixtureof1:10.1MBu
4
NBF
4
/PhCN

andAUSSBTtoluenesolution,scanrate:50mVS
¡1
176
8.6PBTpreparationbyCEinamixtureof1:10.1MBu
4
NBF
4
/PhCN
andAUSSBTtoluenesolution,currentdensity:1mAcm
¡2
177
8.7CyclicVoltammtryofPBTpreparedinamixtureof1:10.1M
Bu
4
NBF
4
/PhCNandtolulenesolutionof(A)AUSSBT,(B)AURSBT,
(C)AU3SBTand(D)AU5SBTonPtelectrodebyCV,scanrate:
20mVS
¡1
178
8.8UV-visspectraofPBTpreparedinamixtureof1:10.1MBu
4
NBF
4
/PhCN
andgoldtoluenesolutionwithsurfactant(A)SSBT,(B)RSBT,
(C)3SBTand(D)5SBTonITOglasselectrodebyCE(1mAcm
¡2
).180

8.9C(1s),S(2p)andAu(4f)XPSspectraofPBT-AUSSBT 182
xix
ListofTables
1.1P-dopingofpolythiophenes¯lmspreparedonplatinumfoil 17
1.2Bindingenergyofdi®erentgoldspecies 35
2.1Electrochemicalpropertiesofmonomers 49
3.1Electrochemicalpropertiesofpolymers 70
3.2UV-visabsorptionofpolymers 84
3.3SurfaceelementsofPBTdopedbyBF
3
andBF
¡
4
90
4.1Bindingenergyofdi®erentsulfurspeciesin5SHBTmonolayeron
Auelectrode 102
5.1SurfacestoichiometryofPBTobtainedonITOSAandITOSASBT
electrodes 129
6.1Particlesizeandsizedistributionofvariousgoldnanoparticles 139
6.2Au(4f)
7=2
spectraofvariousthienylthiolatestabilizedgoldnanopar-
ticles 145
7.1CapacitanceofindividualparticlescalculatedfromCVandDPV.162
8.1PropertiesofPBTincorporatedwithvariousgoldnanoparticles 181
8.2Au(4f)spectraofPBTincorporatedwithvariousthienylthiolate
stabilizedgoldnanoparticles 183
xx
10.1Sensitivityfactors(f)ofelements 189
xxi

Abbreviations
CV: CyclicVoltammetry
DPV: Di®erentialPulseVoltammetry
CE: Chronopotentiometry
CA: Chronoamperometry
UV-vis: UltraVioletandVisibleSpectroscopy
XPS: X-RayPhotoelectronSpectroscopy
TEM: TransmissionElectronMicroscopy
AFM: AtomicForceMicroscopy
NMR: NuclearMagneticResonance
FE-SEM: FieldElectron-ScanningElectronMicroscopy
FT-IR: FourierTransformInfraredSpectroscopy
SAM: SelfAssembledMonolayer
SCE: SaturatedCalomelElectrode
FWHM: FullWidthatHalfMaximum
SET: SingleElectronTransfer
E
g
: BandGapEnergy
E
on
: OnsetPotential
E
pa
: OxidationPotential
E
pc
: ReductionPotential
I
pa

: AnodicPeakCurrent
I
pc
: CathodicPeakCurrent
E
f
: EnergyatFermiLevel
D
n
: NumberAverageDiameterofParticles
D
w
: WeightAverageDiameterofParticles
xxii
3OCT: 3-octyl-thiophene
BT: 2,2'-bithiophene
3OMEBT: 3-methoxy-2,2'-bithiophene
3OCBT: 3-octyl-2,2'-bithiophene
3BRBT: 3-bromo-2,2'-bithiophene
3SOCBT: 3-octylthio-2,2'-bithiophene
DOCBT: 3,3'-dioctyl-2,2'-bithiophene
DOBUBT: 3,3'-dibutoxy-2,2'-bithiophene
DSOCBT: 3,3'-dioctylthio-2,2'-bithiophene
DCLBT: 3,3'-dichloro-2,2'-bithiophene
DBRBT: 3,3'-dibromo-2,2'-bithiophene
DIBT: 3,3'-diiodo-2,2'-bithiophene
BRHEBT: 3-bromo-3'-hexyl-2,2'-bithiophene
BRSOCBT: 3-bromo-3'-octylthio-2,2'-bithiophene
3SHBT: Dithieno[3,2-c:2',3'-e][1,2]dithiin
3SHBT: 3-mercapto-2,2'-bithiophene

5SHBT: 5-mercapto-2,2'-bithiophene
RSHBT: 3-mercapto,3'-octyl-2,2'-bithiophene
RSBRBT: 3-bromo-3'-octylthio-2,2'-bithiophene
P3OMEBT: Poly(3-methoxy-2,2'-bithiophene)
P3OCBT: Poly(3-octyl-2,2'-bithiophene)
P3BRBT: Poly(3-bromo-2,2'-bithiophene)
P3SOCBT: Poly(3-octylthio-2,2'-bithiophene)
PDOCBT: Poly(3,3'-dioctyl-2,2'-bithiophene)
PDOBUBT: Poly(3,3'-dibutoxy-2,2'-bithiophene)
PDSOCBT: Poly(3,3'-dioctylthio-2,2'-bithiophene)
PDCLBT: Poly(3,3'-dichloro-2,2'-bithiophene)
PDBRBT: Poly(3,3'-dibromo-2,2'-bithiophene)
PDIBT: Poly(3,3'-diiodo-2,2'-bithiophene)
PBRHEBT: Poly(3-bromo-3'-hexyl-2,2'-bithiophene)
AUSSBT: Dithieno[3,2-c:2',3'-e][1,2]dithiinStabilizedAuNanoparticle
AU3SBT: 3-mercapto-2,2'-bithiopheneStabilizedAuNanoparticle
AU5SBT: 5-mercapto-2,2'-bithiopheneStabilizedAuNanoparticle
xxiii
AURSBT: 3-mercapto,3'-octyl-2,2'-bithiopheneStabilizedAuNanoparticle
AUBRSBT: StabilizedAuNanoparticle