Organic Photovoltaics

Christoph J. Brabec is full professor at the University of Erlangen-Nurnberg, Germany heading the chair i-MEET "materials for electronics and energy technology" at the department of material science. After completing his PhD in 1995, he joined the group of Prof. Alan Heeger at the University of Santa Barbara, USA, for a sabbatical in 1996, and continued to work on the opto-electronic properties of organic semiconductors as assistant professor at the University of Linz with Prof. Serdar Sariciftci. In 1998, he became senior scientist at the Christian Doppler Laboratory working on organic solar cells, which he left in 2001 to join Siemens Corporate Technology as project leader for organic semiconductor devices. From 2004 on he became headed the printed photovoltaics programme at Konarka Technologies as director and later on as CTO, before he joined Erlangen university in 2009. He finished his habilitation in physical chemistry at the Johannes Kepler University of Linz in 2003, and is author or co-author of more than 250 papers and inventor or co-inventor of over 100 patents. He is co-chair of the editorial board of the Wiley-VCH journal "Advanced Energy Materials". Ullrich Scherf is full professor for Macromolecular Chemistry at Bergische Universitat Wuppertal, Germany, and director of the interdisciplinary research cluster "Institute for Polymer Technology". He studied chemistry at Friedrich-Schiller-Universitat Jena, Germany, obtaining his PhD in 1988 and subsequently spent one postdoctoral year with Heinz Penzlin, Saxonian Academy of Sciences, Jena. He joined the Klaus Mullen group at Max Planck Institute for Polymer Research in Mainz in 1990 and completed his habilitation in 1996 on polyarylenetype ladder polymers. Ullrich Scherf was Professor for Polymer Chemistry at Potsdam University (2000-02) and, since 2002, Professor for Macromolecular Chemistry at Wuppertal University. He has authored or co-authored more than 500 refereed journal papers. Vladimir Dyakonov is full professor of experimental physics at the University of Wurzburg, Germany, and scientific director of the Bavarian Centre of Applied Energy Research (ZAE Bayern) in Wurzburg. He obtained his diploma degree in physics from the University of Saint Petersburg, Russia his PhD from the A. F. Ioffe-Institute in Russia and his habilitation degree from the University of Oldenburg, Germany, in 1986, 1996 and 2001, respectively. From 1996 to 1998, he worked as a post-doctoral fellow at the universities of Antwerp, Belgium, and Linz, Austria.

• PART I: Materials for Thin Film Organic Photovoltaics OVERVIEW OF POLYMER AND COPOLYMER MATERIALS FOR ORGANIC PHOTOVOLTAICSIntroductionEarly EffortsToward Devices with 5% EfficienciesNovel Thiopene-Containing PolymersFluorene-Containing MoleculesCarbazole-Based CopolymersNew Heterocyclic PolymersPolymers Based on Other Types of Building BlocksConclusions THIOPHENE-BASED HIGH-PERFORMANCE DONOR POLYMERS FOR ORGANIC SOLAR CELLSIntroductionBandgap EngineeringCharge Generation in Bulk Heterojunction Organic Solar CellsPolyalkylthiophenesPolyalkylthiophene/PCBM BlendsPolythiophene CopolymersSide Chain Functionalized P3AT DerivativesThird-Generation PolythiophenesThiophene-Based Push?Pull CopolymersBenzo[1,2-b:4,5-b']dithiophene-Based PolymersCyclopental[2,1-b:3,4-b']dithiophene-Based PolymersIndacenodithiophene-Based PolymersConclusion and Outlook MOLECULAR DESIGN OF CONJUGATED POLYMERS FOR HIGH-EFFICIENCY SOLAR CELLSIntroductionStructural Features of Conjugated Polymers"D-A" ApproachQuinoid ApproachSummary and Outlook SOLUTION-PROCESSED MOLECULAR BULK HETEROJUNCTION SOLAR CELLSIntroductionMonochromophoric MoleculesMultichromophoric MoleculesSummary and Future Directions VACUUM-PROCESSED DONOR MATERIALS FOR ORGANIC PHOTOVOLTAICSIntroductionPlanar and Bulk Heterojunction Solar CellsSummary and Future Prospects POLYMER-NANOCRYSTAL HYBRID SOLAR CELLSIntroductionSemiconductor NanocrystalsWorking Principles and Device StructureEvolution of Polymer-NC Hybrid Solar CellsRecent Approaches for Overcoming Current LimitationsNovel Concepts and PerspectivesSummary and Outlook FULLEREN-BASED ACCEPTOR MATERIALSIntroduction and OverviewFullerenes as n-Type SemiconductorsFullerene DerivativesDerivatives of C70 and C84Fullerene BisadductsEndohedral CompoundsCommercialization of Fullerene Derivatives POLYMERIC ACCEPTOR SEMICONDUCTORS FOR ORGANIC SOLAR CELLSIntroductionBasics Principles and Operation for Organic Solar CellsPolymeric Acceptor SemiconductorsConclusions and Perspective WATER/ALCOHOL-SOLUBLE CONJUGATED POLYMER-BASED INTERLAYERS FOR POLYMER SOLAR CELLSIntroductionThe Development of Water/Alcohol-Soluble Conjugated Polymers as Interlayer MaterialsInterface Engineering for Polymer Solar CellsDiscussion of the Working MechanismSummary METAL OXIDE INTERLAYERS FOR POLYMER SOLAR CELLSIntroductionConventional StructureInverted StructureTandem StructureAdditional Oxides (Cr2O3, CuOx, PbO)Conclusions PART II: Device Physics of Thin Film Organic Photovoltaics BIMOLECULAR AND TRAP-ASSISTED RECOMBINATION IN ORGANIC BULK HETEROJUNCTION SOLAR CELLSIntroductionRecombination at Open CircuitTrap-Assisted Recombination at Open CircuitInvestigation of the Nature Recombination by Electroluminescence MeasurementsBimolecular Recombination Strength in Organic BHJ Solar CellsBimolecular Recombination Losses Under Short-Circuit ConditionsEffect of Bimolecular Recombination on Fill Factor and EfficiencyConclusions ORGANIC PHOTOVOLTAIC MORPHOLOGYIntroductionOrder in Bulk HeterojunctionsNanoscale Morphology in Bulk HeterojunctionsPhases in a Bulk HeterojunctionStructure of the Interface between PhasesIn Situ Measurements of Morphology Development INTERCALATION IN POLYMER:FULLERENE BLENDSIntroductionMethods for Detecting Molecular MixingFactors Affecting Molecular MixingThe Effect of Molecular Mixing on Electronic Properties and Solar CellsConclusions ORGANIC TANDEM SOLAR CELLSIntroduction and Working PrincipleMeasurement TechniquesEfficient Intermediate Charge Carrier RecombinationLight ManagementChoice of MaterialsParallel Tandem ArchitecturesNew Tandem Solar Cell ConceptsConclusions SOLID-STATE DYE-SENSITIZED SOLAR CELLSIntroductionWorking Principles of Solid-State Dye-Sensitized Solar CellsLoss Mechanims in Solid-State Dye-Sensitized Solar CellsSolid-State Dye-Sensitized Solar Cells with Spiro-OMeTAD as Hole ConductorHybrid Solar Cells with Absorbing Hole ConductorsOrdered Nanostructures for Solid-State Dye-Sensitized Solar CellsSummary and Outlook PART III: Technology for Thin Film Organic PV REEL-TO-REEL PROCESSING OF HIGHLY CONDUCTIVE METAL OXIDESIntroductionMaterialsDeposition TechnologyEquipmentAlternative Approaches FLEXIBLE SUBSTRATE REQUIREMENTS FOR ORGANIC PHOTOVOLTAICSIntroductionPolyester SubstratesProperties of Base SubstratesConcluding Remarks ADHESIVES FOR ORGANIC PHOTOVOLTAIC PACKAGINGIntroductionEncapsulation Process for Organic PhotovoltaicsChemistry Aspects of Barier AdhesivesBarrier Performance of OPV AdhesivesConclusions ROLL-TO-ROLL PROCESSING OF POLYMER SOLAR CELLSIntroductionThe Roll-to-Roll ProcessStructure of ModulesCoating and Printing Techniques for PSC MaterialsRoll-tol-Roll Printing of ElectrodesR2R EncapsulationRoll-to-Roll CharacterizationFuture and Outlook CURRENT AND FUTURE DIRECTIONS IN ORGANIC PHOTOVOLTAICSScientific and Technological AspectsCommercial ApplicationsChallenges and Major Hurdles Index