Engineering Infra-Red Photon Absorbing Materials for Organic Solar Cells Jason D'Souza

200 Pages·2009·8.04 MB·English

Engineering Infra-Red
Photon Absorbing Materials for
Organic Solar Cells

By

Jason D’Souza

A thesis submitted in conformity with the requirements
for the degree of Master of Applied Science and Engineering
Graduate Department of Chemical Engineering and Applied Chemistry
University of Toronto

© Copyright by Jason D’Souza, 2009
Engineering Infra-Red Photon Absorbing Materials for Organic Solar
Cells
Jason D’Souza
Master of Applied Science and Engineering
Graduate Department of Chemical Engineering and Applied Chemistry
University of Toronto
2009

Abstract:

This thesis aims to investigate different infrared absorbing molecules and how their properties
are affected by their incorporation into polymer nanoparticles. Metal-free phthalocyanine-H Pc,
2
uranyl super phthalocyanine-USPc, and europium bisphthalocyanine were studied-EuPc ; the
2
latter two capable of IR absorption. Due to the discovery of USPc’s moisture sensitivity, only
H Pc and EuPc were derivatized to facilitate encapsulation in polystyrene nanoparticles through
2 2
a miniemulsion polymerization. These novel phthalocyanines attained loadings of up to 41wt%
and exhibit substantial broadening of absorption peaks. Furthermore, the EuPc loaded particles
2
also reveal an unprecedented gain in extinction coefficient of the NIR and radical absorption
peaks. The leaching behavior of the dye was also studied, as this had not been undertaken in the
literature, and revealed the need for a method of polymerizing/chemically binding
phthalocyanines into nanoparticles; with preliminary steps taken to realize this goal.

ii
Acknowledgements

Two years is a long time to dedicate to a project and I am so thankful for all the people who have
helped along the way. Firstly, I would like to thank my mom, dad and brother who have
supported me in so many countless ways that I am forever grateful. I am also very grateful to my
friends who kept my spirits high with their support and companionship. Included in the previous
group is Bender lab members past and present. It was always a fun time in the lab knowing that I
was surrounded by friends and the many great memories from our fun times outside of the lab. I
would especially like to thank Andrew Paton who was a constant source of helpful tips, advice
and also helped tremendously with the SEM analysis. Finally, I would like to thank Professor
Bender. Your advice, knowledge and support helped guide me and provide structure, which was
paramount to the completion of this work. I am very grateful for the knowledge and experience I
have gained from working in your lab and the opportunity to be part of such exciting research.

iii
TABLE OF CONTENTS
ABSTRACT:  II
ACKNOWLEDGEMENTS  III
LIST OF TABLES  VI
LIST OF FIGURES  VII
TABLE OF ABBREVIATIONS  IX
1 INTRODUCTION  1
2 LITERATURE REVIEW:  3
2.1 HISTORY OF SOLAR CELLS  3
2.1.1 THE 1ST GENERATION OF SOLAR CELLS – SILICON  4
2.1.2 THE 2ND GENERATION OF SOLAR CELLS – INORGANIC THIN FILMS  5
2.1.3 THE 3RD GENERATION SOLAR CELLS ‐ OSC  6
2.1.4 THE BENDER CELL:  13
2.2 COLOUR THEORY  14
2.3 PHYSICS OF AN OPV  20
2.4 PHOTOSYNTHESIS  25
2.5 DYES AND PIGMENTS  27
2.6 PHTHALOCYANINES (PC)  33
2.7 ABSORPTION OF THE INFRA‐RED REGION OF THE SPECTRUM  35
2.7.1 URANYL SUPERPHTHALOCYANINE, USPC  37
2.7.2 LANTHANIDE BISPHTHALOCYANINES, BISPCS  41
2.8 COORDINATION CHEMISTRY OF PHTHALOCYANINES  47
2.9 MINIEMULSION POLYMERIZATION OF DYE‐LOADED NANOPARTICLES  51
2.9.1 PRINCIPLES OF MINIEMULSION  52
2.9.2 ENCAPSULATION OF DYES  57
3 THESIS STATEMENT  59
4 METHODS AND RESULTS  61
4.1 POLYMER NANOPARTICLE SYNTHESES  61
4.2 SYNTHESIS OF PHTHALONITRILES FOR POLYMERIZATION  66
4.2.1 SYNTHESIS OF A PHTHALONITRILE WITH DYE BEHAVIOUR, PDPN  66
4.3 SYNTHESIS OF H2PC  71
4.4 SYNTHESIS OF URANYL‐SUPERPHTHALOCYANINE (USPC)  77
4.4.1 SYNTHESIS #1  77
iv
4.4.2 SYNTHESIS #2  79
4.5 SELECTION AND SYNTHESIS OF LANTHANIDE BISPCS  89
4.5.1 SYNTHESIS OF EUROPIUM BISPC, EUPC2  90
4.5.2 SYNTHESIS OF LANTHANUM BISPC, LAPC2  97
4.6 DYE SYNTHESES  103
4.6.1 H2PC DYE SYNTHESIS  103
4.6.2 EUPC2 DYE SYNTHESIS  105
4.7 SYNTHESIS OF DYE LOADED NANOPARTICLES  111
4.7.1 SYNTHESIS OF H2PC‐DYE LOADED NANOPARTICLES  111
4.7.2 SYNTHESIS OF EUPC2‐DYE LOADED NANOPARTICLES  121
5 WORK TOWARDS FUTURE GOALS/ RECOMMENDATIONS  126
5.1 SYNTHESIS OF A VINYL PHTHALONITRILES  126
5.1.1 KINETICS EXPERIMENTS  134
5.2 SYNTHESIS OF HYDROXYL PHTHALONITRILES  136
5.3 RECOMMENDATIONS  144
6 CONCLUSION  147
7 APPENDICES:  1
7.1 THE PYRROLE DERIVED MACROCYCLE FAMILY  1
7.2 VARIATION IN SYNTHESIS OF EUPC2  2
7.3 CHEMICAL DATA  2
7.4 EQUIPMENT DATA:  4
7.5 SEM ANALYSIS OF PS‐ NANOPARTICLES  5
7.6 CENTRIFUGATION OF NANOPARTICLES FROM SOLUTION  8
7.7 EUPC2 SUPPLEMENTARY ANALYSIS DATA  8
7.8 LAPC2 SUPPLEMENTARY ANALYSIS DATA  10
7.9 GPC ANALYSIS OF EUPC2 ‐ DYE  12
7.10 SEM ANALYSIS OF H2PC‐DYE LOADED NANOPARTICLES  16
7.11 LEACHING DETERMINATION FOR H2PC‐DYE  21
7.12 SEM ANALYSIS OF EUPC2‐DYE LOADING NANOPARTICLES  22
7.13 CHLOROFORM/HEXANE CALIBRATION DATA FOR EUPC2‐DYE  24
7.14 LOADING/LEACHING DETERMINATION FOR EUPC2‐DYE  25
7.15 HPLC DATA FROM APPN SYNTHESIS – DMF/DMSO  27
7.16 HPLC DATA FROM SYNTHESIS OF VPPN  32
7.17 PREDICTED NMR DATA FOR VPPN SYNTHESIS  34
7.18 PROPANOL REACTION KINETICS OF EUPC2 SYNTHESIS  35
7.19 ANALYSIS OF BPAPN SYNTHESIS  36
8 REFERENCES:  38

v
List of Tables

TABLE 1: TYPES OF ORGANIC PIGMENTS......................................................................................................................30
TABLE 2: SYNTHESIS DETAILS OF PS-NANOPARTICLES...............................................................................................61
TABLE 3: SEM ANALYSIS OF NANOPARTICLES.............................................................................................................63
TABLE 4: SEM ANALYSIS BY IMAGE J SOFTWARE........................................................................................................63
TABLE 5: DRYING PARTICLES THROUGH SOLVENT WASHES........................................................................................65
TABLE 6: PHTHALONITRILE DERIVATIVE FOR INCORPORATION INTO A NANOPARTICLE..............................................66
TABLE 7: SUMMARY OF HPLC DATA FOR PDPN SYNTHESIS........................................................................................68
TABLE 8: EA RESULTS FOR LI2PC.................................................................................................................................74
TABLE 9: SOLVENTS FOR REMOVING H2PC...................................................................................................................87
TABLE 10: REACTION SCHEMES FOR SYNTHESIS OF EUPC2..........................................................................................91
TABLE 11: SUMMARY OF EUPC2 REACTIONS................................................................................................................91
TABLE 12: REACTION SCHEMES FOR LABISPC.............................................................................................................98
TABLE 13: LABISPC STRUCTURES................................................................................................................................98
TABLE 14: SUMMARY OF LABISPC REACTIONS............................................................................................................98
TABLE 15: REACTION III GPC OF CHROMATOGRAPHY SECTION #3 OF LAPC2 SYNTHESIS........................................101
TABLE 16: GPC RESULTS OF H2PC-DYE....................................................................................................................105
TABLE 17: YIELD AND PURITY DATA OF EUPC2 - DYE...............................................................................................106
TABLE 18: REACTION MONITORING OF EUPC2-DYE SYNTHESIS................................................................................107
TABLE 19: SUMMARY OF COMPOSITION DATA FROM GPC ANALYSIS.........................................................................108
TABLE 20: GPC ANALYSIS OF EUPC2-DYE.................................................................................................................110
TABLE 21: SUMMARY OF H2PC NANOPARTICLE SYNTHESES:.....................................................................................113
TABLE 22: SAMPLE OF SEM IMAGES OF NANOPARTICLES.........................................................................................114
TABLE 23: CREATION OF CALIBRATION CURVES FOR H2PC-DYE IN CHLOROFORM AND HEXANE.............................116
TABLE 24: DYE CONTENT ANALYSIS.........................................................................................................................118
TABLE 25: LOADING DETERMINATION OF NANOPARTICLES FROM REACTION 6-20%, 7-35%, 8-50%........................118
TABLE 26: DETERMINATION OF A SOLVENT FOR THE LEACHING STUDY.....................................................................119
TABLE 27: SUMMARY OF EUPC2 NANOPARTICLE SYNTHESES....................................................................................122
TABLE 28: SAMPLE OF SEM IMAGES AND DRIED PARTICLES......................................................................................122
TABLE 29: LOADING AND LEACHING DETERMINATION OF EUPC2 PARTICLES...........................................................123
TABLE 30: SUMMARY OF OBSERVATIONS FOR SOLID-STATE SPECTRA......................................................................124
TABLE 31: POLYMERIZABLE PHTHALONITRILES FOR DYE LOADING IN NANOPARTICLES..........................................127
TABLE 32: SUMMARY OF HPLC DATA FOR APPN SYNTHESIS...................................................................................129
TABLE 33: SOLVENT EXTRACTION HPLC RESULTS...................................................................................................130
TABLE 34: SUMMARY OF HPLC ANALYSIS OF VPPN SYNTHESIS..............................................................................132
TABLE 35: NMR DATA FOR VPPN.............................................................................................................................133
TABLE 36: BOILING POINTS OF ALCOHOLS................................................................................................................134
TABLE 37: UV-VIS ANALYSIS OF REACTION AND FINAL PRODUCT.............................................................................135
TABLE 38: HPLC SUMMARY OF BPAPN SYNTHESIS..................................................................................................137
TABLE 39: H-NMR ANALYSIS OF POWDER 1.............................................................................................................140
TABLE 40: H-NMR ANALYSIS OF POWDER 2.............................................................................................................141
TABLE 41: FTIR ANALYSIS OF BOTH HPPN POWDERS...............................................................................................142

vi
List of Figures
FIGURE 1: RESEARCH PLAN TO DEVELOP A NOVEL PAM...............................................................................................2
FIGURE 2: PROGRESS IN SOLAR CELL TECHNOLOGIES [2]..............................................................................................3
FIGURE 3: CSS DEPOSITION IS USED TO PRODUCE LARGE AREA THIN FILM SC [4]..........................................................6
FIGURE 4: OPERATION OF PLANAR, BILAYER, BHJ AND DSSC OPV DEVICES...............................................................8
FIGURE 5: COMMON CONJUGATED POLYMERS AND P3HT ABSORPTION CHARACTERISTICS [7]......................................9
FIGURE 6: STRUCTURAL EFFECT ON BAND-GAP [8].......................................................................................................10
FIGURE 7: TEM OF A 1UM X 1UM FILM OF A PCBM CONTAINING FILM [10]................................................................11
FIGURE 8: INORGANIC NANOCRYSTALS SIZE DEPENDENT PROPERTIES AND MORPHOLOGY [12]...................................11
FIGURE 9: LEFT- SCHEMATIC OF A DSSC AND HOLE TRANSPORTING MOLECULE, RIGHT-TYPICAL DYE N-719 [13]....12
FIGURE 10: SCHEMATIC OF THE PROPOSED OSC..........................................................................................................14
FIGURE 11: ILLUSTRATION OF THE DIVERSITY OF INTERACTIONS OF LIGHT WITH MATTER [14]....................................15
FIGURE 12: ENERGY LEVEL BANDS IN METALS, SEMICONDUCTORS AND INSULATORS [14].........................................17
FIGURE 13: DEPENDENCE OF WAVELENGTH ON SCATTERING [14]................................................................................19
FIGURE 14: SCHEMATIC OF PROPOSED OSC.................................................................................................................21
FIGURE 15: ARRANGEMENT OF ENERGY LEVELS.........................................................................................................23
FIGURE 16: DIAGRAM OF NATURAL PHOTOSYNTHESIS [35]..........................................................................................26
FIGURE 17: A) STRUCTURE OF CHLOROPHYLL-A; B) SEPARATION OF CHARGE AT REACTION CENTER [35].................26
FIGURE 18: ABSORPTION BROADENING EFFECT FOR A PIGMENT RED 179...................................................................29
FIGURE 19: SCHEMATIC OF MOLECULAR INTERACTIONS OF A PHTHALOCYANINE.......................................................31
FIGURE 20: INTERACTIONS BETWEEN CRYSTALS..........................................................................................................32
FIGURE 21: MOLECULAR STRUCTURES OF PHTHALOCYANINES AND ANALOGS...........................................................34
FIGURE 22: HYPERCHEM 3D VISUALIZATIONS OF BSUBPC, PC, AND USPC................................................................34
FIGURE 23: SOLAR IRRADIATION..................................................................................................................................35
FIGURE 27: CRYSTAL STRUCTURAL DETERMINATION OF USPC [52]...........................................................................40
FIGURE 28: A) PPP PREDICTION OF HOMO-LUMO [54], B) UV-VIS SPECTRA OF USPC [49]....................................41
FIGURE 29: ELEMENTS CIRCLED TWICE INDICATE ELEMENTS THAT FORM SANDWICHES [56].......................................42
FIGURE 30: ILLUSTRATION OF LANTHANIDE SIZE EFFECT ON NIR ABSORPTION..........................................................44
FIGURE 31: SYNTHESIS METHODS FOR LANTHANIDE BISPCS.......................................................................................45
FIGURE 32: ILLUSTRATION OF HOW THE LIGAND AFFECTS ORBITAL ENERGY...............................................................48
FIGURE 33: H2PC ORBITALS FROM HYPERCHEM SOFTWARE A) HUMO B) LUMO.....................................................49
FIGURE 35: EFFECT OF IONIC RADIUS ON STABILITY.....................................................................................................50
FIGURE 36: ROLE OF URANYL IN LIGAND METAL INTERACTION...................................................................................51
FIGURE 37: DIAGRAM OF LENGTH SCALE AND MOLECULAR ARRANGEMENTS..............................................................52
FIGURE 38: SCHEMATIC OF A) EMULSION B) MINIEMULSION C) MICROEMULSION [39].................................................53
FIGURE 39: HOMOGENIZATION FROM ULTRASONICATION (US) IN MINIEMULSION [39]................................................55
FIGURE 40: CHANGE IN PARTICLE SIZE WITH TIME [39]................................................................................................57
FIGURE 41: EFFECT OF DYE LOADING ON MORPHOLOGY.............................................................................................58
FIGURE 42: SYNTHESIS SCHEME FOR PDPN.................................................................................................................67
FIGURE 43: SYNTHESIS SCHEME FOR H2PC SYNTHESIS................................................................................................71
FIGURE 44: UV-VIS SPECTRA OF H2PC........................................................................................................................72
FIGURE 45: SYNTHESIS SCHEME OF LI2PC....................................................................................................................73
FIGURE 46: UV-VIS OF LI2PC IN DMA A) LITERATURE [24] B) CURRENT WORK........................................................75
FIGURE 47: SYNTHESIS SCHEME FOR H2PC..................................................................................................................75
FIGURE 48: PURITY OF H2PC FROM TGA ANALYSIS.....................................................................................................76
FIGURE 49: SYNTHESIS SCHEME FOR USPC..................................................................................................................78
FIGURE 50: USPC AND H2PC UV-VIS SPECTRA..........................................................................................................79
FIGURE 51: TWO-STEP SYNTHESIS OF USPC.................................................................................................................80
FIGURE 52: EXPERIMENTAL SET-UP FOR URANYL SALT COMPLEXATION....................................................................81
FIGURE 53: PRODUCTION OF USPC AND H2PC DURING REACTION................................................................................83
FIGURE 54: COMPARISON OF USPC PRODUCTION TO H2PC..........................................................................................84
FIGURE 55: PREFERENTIAL DISSOLUTION OF H2PC IN DMF.........................................................................................85
FIGURE 56: PREFERENTIAL SELECTION OF USPC IN TCB.............................................................................................86
FIGURE 57: ILLUSTRATES DECREASE IN H2PC AFTER WASHES.....................................................................................87
FIGURE 58: DEGRADATION OF USPC............................................................................................................................88
vii
FIGURE 59: SIMULATED IR ABSORPTION OF LA, EU AND ER BISPC BASED ON DATA FROM FAN-LU[68].....................90
FIGURE 60: TYPICAL COLUMN CHROMATOGRAPHY SET-UP:.......................................................................................93
FIGURE 61: UV-VIS OF EUPC2......................................................................................................................................94
FIGURE 62: EUPC2 UV-VIS-NIR SPECTRA WITH BROAD NIR ABSORPTION PEAK........................................................96
FIGURE 63: FTIR OF EUPC2.........................................................................................................................................97
FIGURE 64: SPECTRA OF PRODUCT AT THE END OF THE REACTION..............................................................................101
FIGURE 65: ABSORPTION SPECTRA OF LAPC2.............................................................................................................102
FIGURE 66: SYNTHESIS SCHEME FOR H2PC-DYE........................................................................................................103
FIGURE 67: COMPARISON OF H2PC TO H2PC DYE.....................................................................................................104
FIGURE 68: COMPARISON OF EUPC2 TO EUPC2 DYE ABSORPTION..............................................................................107
FIGURE 69: SYNTHESIS SCHEME FOR EUPC2-DYE......................................................................................................109
FIGURE 70: UV-VIS-NIR OF EUPC2-DYE..................................................................................................................111
FIGURE 71: MINIEMULSION PROCEDURE WITH PREMIXING OF MONOMER WITH DYE..................................................112
FIGURE 72: PARTICLES BEFORE AND AFTER ACN WASHES........................................................................................115
FIGURE 73: THE SOLID-STATE SPECTRA OF H2PC - DYE LOADED NANOPARTICLES....................................................120
FIGURE 74: SOLID-STATE SPECTRA OF EUPC2 NANOPARTICLES.................................................................................124
FIGURE 75: COMPARISON OF NIR ABSORPTION..........................................................................................................125
FIGURE 76: REACTION SCHEME FOR THE SYNTHESIS OF APPN..................................................................................127
FIGURE 77: BSUBPC WOULD NOT POLYMERIZE WITH ALLYL GROUP..........................................................................130
FIGURE 78: REACTION SCHEME FOR VPPN SYNTHESIS..............................................................................................131
FIGURE 79: H-NMR FROM REFERENCE [60]..............................................................................................................133
FIGURE 80: SYNTHESIS SCHEME OF BPAPN...............................................................................................................137
FIGURE 81: SYNTHESIS OF HPPN................................................................................................................................138
FIGURE 82: IDEAS FOR CREATING A POLYMERIZABLE BISPC......................................................................................143
FIGURE 83: POST FUNCTIONALIZATION TO CREATE A VINYL GROUP..........................................................................144

viii
Table of Abbreviations

Acronym LUMO Lowest unoccupied molecular
acac acetylacetonate orbital
ADP Adenosine diphosphate MEG multiple exciton generation
APPn 4-(2-allylphenoxy) MeOH Methanol
phthalonitrile NADPH Nicotinamide adenine dinucleotide
a-Si amorphous silicon solar cell phosphate
ATP Adenosine triphosphate NIR Near infra-red
BHJ Bulk heterojunction NMP n- Methylpyrrolidone
BisPc bisphthalocyanine NMR Nuclear magnetic resonance
BPAPn 4-(4-(2-(4-hydroxyphenyl)propan- OH hydroxyl
2yl)phenoxy) phthalonitrile OPV Organic Photovoltaics
BSubPc Boron Subphthalocyanine OSC Organic Solar Cell
CF Chloroform PAM Photon Absorbing Material
CIGS Copper-Indium-Gallium-Selenide Pc Phthalocyanine
compounds PCBM Phenyl-C61-butyric acid methyl
c-Si Crystalline silicon ester
CSS close spaced sublimation PDPn 4-(3-pentadecylphenoxy)
CTM Charge transporting material phthalonitrile
D-A Donor-Acceptor PE Polyethylene
DBU 1,8-Diazabicyclo [5.4.0.]undec-7- poly-si Polycrystalline silicon
ene PS Polystyrene
DCM Dichloromethane PV Photovoltaics
DMA dimethylacetamide PVC Polyvinyl chloride
DMF dimethylformamide RPM Revolutions per minute
DMSO Dimethyl sulfoxide RT Room temperature
DSSC Dye Sensitized Solar Cells SC Solar Cell
DVB Divinylbenzene SDBS Sodium dodecylbenzene sulfonate
EA Elemental Analysis SEM Scanning Electron Microscopy
E bandgap TCB 1,2,4-trichlorobenzene
g
ETM Electron transporting material THF Tetrahydrafuran
EuBisPc, Europium Bisphthalocyanine TMAB tertmethylammonium bromide
EuPc TPP tetraphenyl porphyrins
2
FRET Forster resonance energy transfer UHP ultrahydrophobe
FTIR Fourier transformed infrared US ultrasonication
GPC Gel permeation chromatography USPc, Uranyl Superphthalocyanine
H Pc Metal-free phthalocyanine UO SPc
2 2
HDTAB hexadecyltertammonium bromide UV Ultraviolet
Hex Hexanes UVVIS Ultraviolet/visible
HOMO Highest occupied molecular orbital V501 4,4′-Azobis(4-cyanovaleric acid)
HPLC High pressure liquid initiator
chromatography VPPn 4-(4-vinylphenoxy)phthalonitrile
HPPn 4-(3-hydroxyphenoxy) phthalonitrile XSC Excitonic Solar Cells
HTM Hole transporting material
IPCE Incident to Photon Conversion
Efficiency
IR Infra-red
LaBisPc, Lanthanum Bisphthalocyanine
LaPc
2
Li Pc dilithiophthalocyanine
2
LnBisPc, Lanthanide Bisphthalocyanine
LnPc
2
ix
1 Introduction

Global climate change, oil depletion, economic woes and a greater divide between the strata of
society are problems inextricably linked that loom over our future. The thread that weaves these
problems together is energy. Our dependence on fossil fuels has led to climate change and our
securing of a dwindling resource has exasperated our economy. Although humanities problems
are more complex than simply fixing our energy needs it is a good place to start.

To solve our problems it seems a combined approach using novel technology to harness
renewable energy to supplement our traditional energy sources, designing with energy efficiency
in mind, and conservation will be needed. Therefore, a truly essential component of both short
and long term ambitions must include harnessing solar energy.

Solar irradiation provides the Earth with 120,000 TW of electromagnetic radiation [1], and will
continue till the death of our Sun some 5 billion years from now. For millennia we have used
solar power that had been concentrated into biomass. Within the past century we skipped a step
and used inorganic silicon solar cells to capture this energy. Beginning with research in the
1960s we took a hint from nature and the process of photosynthesis and created organic
photovoltaic (OPV) devices, aka organic solar cells (OSC).

OSC show great promise because they can be printed using traditional printing
techniques into thin flexible sheets which enable a wider range of applications and a reduction in
manufacturing costs compared to traditional silicon solar cells. With suitable efficiencies and a
low cost they promise to be a significant contributor to our future energy system.
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