TiO2 Nanotube Arrays: Synthesis, Properties, and Applications

379 Pages·2009·7.581 MB·English

by  Craig A. Grimes, Gopal K. Mor (auth.)

TiO Nanotube Arrays
2
Craig A. Grimes Gopal K. Mor
l
TiO Nanotube Arrays
2
Synthesis, Properties, and Applications
CraigA.Grimes GopalK.Mor
PennsylvaniaStateUniversity PennsylvaniaStateUniversity
ElectricalEngineering MaterialsResearchInstitute
Department UniversityPark,PA16802
UniversityPark,PA16802 USA
USA [email protected]
[email protected]
ISBN978-1-4419-0067-8 e-ISBN978-1-4419-0068-5
DOI10.1007/978-1-4419-0068-5
SpringerDordrechtHeidelbergLondonNewYork
LibraryofCongressControlNumber:2009930642
#SpringerScienceþBusinessMedia,LLC2009
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Preface
As the title of this book implies, we examine the fabrication, properties, and
different applications of highly ordered vertically oriented TiO nanotube arrays
2
madebyTianodization.SincethefirstreportofthehighlyorderedTiO nanotube
2
arrays by Gong et al. (J Mater Res 16:3331–3334, 2001), the field has grown so
rapidlyastomakeitdifficulttosummarizethescopeofallrelatedwork.Builtupon
a suite of synthesis chemistries that enable significant differences in nanotube
morphologies,theTiO nanotubearrayshavedemonstratedremarkableproperties
2
that have successfully given rise to a large number of diverse applications that
include, but are certainly not limited to, super capacitors, solar cells, drug eluting
surfaces, hydrogen sensors, biofiltration membranes, and photoelectrochemical
cells for the solar generation of hydrogen. It appears, for the moment, impossible
tocompletelycanvasthefieldasitmovesmorerapidlythanonecanreportonit.Be
thatasitmaywehavetriedtoatleasttouchonkeyaspectsofthefield,reviewing
thecontributionsmadebyvariousresearchgroupstothefabrication,andapplica-
tionofthenanotubearrays,andapologizetothoseauthorsofsignificantworkwe
mayhaveoverlooked.
The book is intended for researchers in the field, which could encompass
undergraduate students, graduate students and beyond. It is meant as both an
introductory work as well as a reference to the field. While the book could be
read cover to cover by those having such energy and interest, the individual
chapters are self-contained per their specific topic. Chapter 1 considers nanotube
arraysynthesistechniques.Chapter2summarizesthestructural,elemental,optical,
mechanical, and electrical properties of the TiO nanotube arrays. Chapter 3
2
examinesuseofTiO nanotubearraysashydrogengassensors.Chapter4considers
2
useofthematerialarchitectureforphotoelectrochemicalwatersplitting.Chapter5
considers application of TiO nanotube arrays to dye-sensitized solar cells and
2
polymer-basedsolidstateheterojunctionsolarcells.Chapter6discussestheuseof
TiO nanotubesinbiologicalapplications,includingtheiruseasabaseforbiosen-
2
sors, drug eluting surfaces, osseointegration, biotemplating, enhanced blood
clotting,andasbiofiltrationmembranes.
v
vi Preface
We wish to thank Emeritus Professor Dale M. Grimes for helpful comments
towardsimprovingthemanuscript,theanonymousreviewersofthebookwhoput
forth many helpful suggestions, and thank the many authors who generously
granted us permission to use their figures in this book, with a particular nod
to Dr. Radim Bera´nek, Department of Chemistry & Pharmacy, University of
Erlangen-Nu¨rnberg,whowaswillingtoredrawsomeofhisfiguresforuseherein.
UniversityPark,PA CraigA.Grimes
GopalK.Mor
Contents
Introduction ................................................................ xiii
1 FabricationofTiO NanotubeArraysbyElectrochemical
2
Anodization:FourSynthesisGenerations ................................. 1
1.1 Introduction ............................................................... 1
1.1.1 TheElectrochemicalAnodizationProcess ........................ 2
1.2 NanotubeArraySynthesisUsingAqueousElectrolytes:
TheFirstGeneration ...................................................... 3
1.2.1 HF-BasedElectrolytes ............................................. 3
1.2.2 TaperedConicalShapeNanotubes ................................ 5
1.2.3 WallThicknessVariation ......................................... 6
1.2.4 UsingHNO /HF ................................................... 7
3
1.2.5 UsingH SO /HF .................................................. 8
2 4
1.2.6 UsingH Cr O /HF ................................................ 8
2 2 7
1.2.7 UsingCH COOH/NH F,H SO /NH F ........................... 9
3 4 2 4 4
1.2.8 UsingH PO /HF,H PO /NH F .................................. 10
3 4 3 4 4
1.3 NanotubeArraySynthesisUsingBufferedElectrolytes:
TheSecondGeneration .................................................. 12
1.3.1 Step-by-StepProcedure:SolutionPreparation,
MixingandpHAdjustment ...................................... 15
1.3.2 SolutionSetPreparation .......................................... 15
1.3.3 AnodizationwithConstantCurrentDensity ..................... 16
1.4 SynthesisofNanotubeArraysUsingPolarOrganicElectrolytes:
TheThirdGeneration .................................................... 18
1.4.1 UsingFormamideandDimethylformamideelectrolyte ......... 18
1.4.2 DimethylSulfoxideElectrolytes ................................. 22
1.4.3 EthyleneGlycolElectrolytes ..................................... 26
1.4.4 DiethyleneGlycolElectrolytes ................................... 34
1.4.5 UsingGlycerolandNH F ........................................ 37
4
1.4.6 Methanol,Water,andHF ........................................ 38
1.5 NanotubeArraySynthesisUsingNon-FluorideBasedElectrolytes:
TheFourthGeneration .................................................. 38
vii
viii Contents
1.5.1 UsingHCl ........................................................ 40
1.5.2 H O AqueousElectrolytes ...................................... 40
2 2
1.5.3 HCl/H O AqueousElectrolytes ................................. 42
2 2
1.6 FabricationofTransparentTiO NanotubesArrays .................... 44
2
1.7 MechanisticModelofNanotubeArrayFormationby
PotentiostaticAnodization .............................................. 48
References .................................................................... 59
2 MaterialPropertiesofTiO NanotubeArrays:Structural,Elemental,
2
Mechanical,Optical,andElectrical ....................................... 67
2.1 Introduction .............................................................. 67
2.2 StructuralandElementalCharacterization .............................. 67
2.2.1 AnodicFormationofCrystallineMetalOxideNanotubes ...... 73
2.2.2 ImprovedCrystallizationviaSolvothermalTreatment .......... 76
2.2.3 PartiallyCrystallineAnatasePhaseNanotubes
byAnodization ................................................... 78
2.3 CharacterizationofDopedTitaniaNanotubes .......................... 79
2.3.1 CarbonIncorporationWithintheNanotubes .................... 79
2.3.2 NitrogenIncorporationWithintheNanotubes ................... 80
2.3.3 Boron-DopedNanotubes ......................................... 82
2.3.4 OrganicBath ...................................................... 82
2.3.5 CdS-CoatedNanotubes ........................................... 83
2.4 OpticalPropertiesofTitaniaNanotubesArrays ........................ 83
2.4.1 FiniteDifferenceTimeDomainSimulation
ofLightPropagationinNanotubeArrays ........................ 83
2.4.2 MeasuredOpticalProperties ..................................... 88
2.4.3 EllipsometricMeasurements ..................................... 92
2.4.4 RamanSpectraMeasurements ................................... 96
2.5 ElectricalPropertyMeasurements ...................................... 97
2.5.1 PhotocurrentTransientMeasurements ........................... 97
2.5.2 CapacitanceMeasurements ....................................... 98
2.6 MechanicalProperties ................................................. 105
References .................................................................. 106
3 TiO NanotubeArrays:ApplicationtoHydrogenSensing ............ 115
2
3.1 Introduction ............................................................ 115
3.2 HighTemperatureSensorsusingTiO NanotubeArrays ............. 117
2
3.3 Self-CleaningRoom-TemperatureHydrogenSensors ................ 121
3.4 Room-TemperatureHydrogenSensorsofEnhancedSensitivity ..... 126
3.4.1 TiO NanotubeArraysonTiFoil ............................... 126
2
3.4.2 TransparentHydrogenSensors .................................. 131
3.5 ExtremeHydrogenGasSensitivitiesatRoomTemperature ......... 132
3.6 TranscutaneousHydrogenMonitoringusingTiO
2
NanotubeArrays ....................................................... 136
3.6.1 CrossInterferenceandCalibration .............................. 137
Contents ix
3.6.2 TranscutaneousHydrogenandLactoseIntolerance ............ 141
References .................................................................. 142
4 TiO NanotubeArrays:ApplicationtoPhotoelectrochemical
2
WaterSplitting ............................................................ 149
4.1 Introduction ............................................................ 149
4.2 PhotoelectrolysisCell ................................................. 150
4.2.1 WaterSplittingEfficiency ....................................... 153
4.2.2 QuantumEfficiencyCalculation ................................ 157
4.3 PhotoelectrolysisUsingUnmodifiedTiO Nanotubes ................ 158
2
4.3.1 ShortNanotubes ................................................. 159
4.3.2 MediumLengthNanotubes ..................................... 161
4.3.3 LongNanotubes ................................................. 164
4.3.4 RoughnessFactor ................................................ 166
4.3.5 EffectofElectrolyteAdditives .................................. 168
4.4 PhotoelectrolysisUsingAnionicandCationicDoped
TiO Nanotubes ........................................................ 170
2
4.4.1 N-DopedTiO Nanotubes ....................................... 170
2
4.4.2 CarbonDopedTiO Nanotubes ................................. 174
2
4.4.3 Sulfur-DopedTiO Nanotubes .................................. 175
2
4.4.4 Boron-DopedTiO Nanotubes .................................. 176
2
4.4.5 Silicon-DopedTiO Nanotubes ................................. 177
2
4.5 PhotoelectrolysisUsingSurface-SensitizedTiO Nanotubes ........ 178
2
4.5.1 CdSSensitizedTiO Nanotubes ................................ 178
2
4.5.2 CdSeSensitizedTiO Nanotubes ............................... 180
2
4.5.3 CdTeSensitizedTiO NanotubeArrays[137] .................. 180
2
4.5.4 WO CoatedTiO Nanotubes ................................... 183
3 2
4.5.5 PtSensitizedTiO Nanotubes ................................... 184
2
4.6 OtherApproaches ..................................................... 185
4.6.1 PolyoxophosphotungstateEncapsulatedin
TiO Nanotubes .................................................. 185
2
4.6.2 LightSensitizedEnzymaticSystem
withTiO Nanotubes ............................................ 186
2
4.7 Self-BiasedPhotoelectrochemicalDiodesUsingCu-Ti-OTernary
OxideNanotubes ...................................................... 188
4.7.1 Fabricationofp-TypeCopperRichCu-Ti-ONanotubes ....... 189
4.7.2 PhotoelectrochemicalProperties ................................ 192
4.7.3 Self-BiasedHeterojunctionPhotoelectrochemicalDiodes ..... 193
4.8 VisiblelightresponsiveTi-Fe-Oternaryoxidenanotubes ........... 195
4.8.1 Benefitsofnanostructuringhematite ............................ 195
4.8.2 Self-AlignedNanoporousIron(III)Oxide ...................... 196
4.8.3 PhotoelectrochemicalPropertiesofSelf–Aligned
NanoporousIron(III)Oxide .................................... 198
4.8.4 FabricationandStructuralCharacterizationof
Ti-Fe-ONanotubes .............................................. 198
x Contents
4.8.5 PhotoelectrochemicalPropertiesofTi–Fe–ONanotubes ....... 203
4.9 CompositionallyGradedTernaryOxideNanotubeArrays ........... 205
References .................................................................. 206
5 Dye-SensitizedandBulk-HeterojunctionsSolarCells:
TiO NanotubeArraysasaBaseMaterial .............................. 217
2
5.1 Introduction ............................................................ 217
5.2 DyeSensitizedSolarCells:OperatingPrinciples ..................... 218
5.2.1 KeyDSCProcesses .............................................. 219
5.2.2 FactorsInfluencingConversionEfficiencies .................... 220
5.2.3 NanocrystallineDSCs ........................................... 223
5.3 SolarCellParameters .................................................. 225
5.4 J–VCharacterizationUnderStandardConditions .................... 226
5.4.1 CalibratingtheSolarSimulatorforDSC
andPolymericSolarCells ....................................... 226
5.4.2 ExperimentalSetup .............................................. 227
5.5 BenefitsofVerticallyOrientedUniformlyAlignedTiO
2
NanotubeArraysinDSCs ............................................. 228
5.5.1 FiniteDifferenceTimeDomainApplicationtoDSCs .......... 229
5.6 LiquidJunctionDSCs ................................................. 234
5.6.1 TransparentTiO NanotubeArraysonFTO
2
CoatedGlass:FrontSideIllumination .......................... 239
5.6.2 TiO NanotubeArraysonTiFoil:BackSideIllumination ..... 245
2
5.6.3 ChargeCollectionProperties .................................... 252
5.6.4 ElectronTransportandRecombinationProperties .............. 253
5.7 PolymerBasedBulkHeterojunctionSolarCells ..................... 258
5.7.1 TiO NanotubesonFTOGlass:PolymericBulk
2
HeterojunctionSolarCells ...................................... 262
5.7.2 SolarCellFabricationandPerformance ........................ 266
5.7.3 TiO -PolymerBasedSolarCells:BackSideIllumination
2
Geometry ........................................................ 270
References .................................................................. 274
6 UseofTiO NanotubeArraysforBiologicalApplications ............ 285
2
6.1 Introduction ............................................................ 285
6.2 Biosensors ............................................................. 286
6.2.1 H O Detection:NanotubesCo-immobilized
2 2
withHRPandThionine ......................................... 286
6.2.2 Co-ImmobilizedwithCytochromec ............................ 288
6.2.3 DetectionofH O andGlucose ................................. 288
2 2
6.3 EnhancedBloodClotting .............................................. 290
6.4 CellAdhesionandOsteoblastGrowth ................................ 292
6.5 DrugElutionfromTiO Nanotubes ................................... 296
2
6.6 HydrophobicNanotubes:SAMsonSurfaceonHydrophilic
Nanotubes .............................................................. 301
Contents xi
6.7 BiologicalFluidsFiltrationandDrugDeliveryUsingTiO
2
NanotubularMembrane ............................................... 302
6.8 ApplicationofPhotocatalyticTiO NanotubeProperties ............. 308
2
References .................................................................. 309
7 ConclusionsandNewDirections ......................................... 315
7.1 Conclusions ............................................................ 315
7.2 SomeFutureDirections ............................................... 320
7.2.1 IntercalationandSupercapacitors ............................... 320
7.2.2 CO ReductionUsingVisibleLight ............................ 329
2
References .................................................................. 340
Index ........................................................................... 347