| publication name | PEDOTs–PCnBMs polymer–fullereneBHJsolarcells: Quantum mechanicalcalculationsofphotovoltaic and photophysicalproperties |
|---|---|
| Authors | A.S. Shalabin, S.AbdelAal,M.M.Assem |
| year | 2012 |
| keywords | |
| journal | Nano Energy(2012) 1, 608–623 |
| volume | Not Available |
| issue | Not Available |
| pages | Not Available |
| publisher | Not Available |
| Local/International | International |
| Paper Link | Not Available |
| Full paper | download |
| Supplementary materials | Not Available |
Abstract
The bandgaps,geometries,electronicstructures,polarizabilities,hyperpolarizabilities,dipole moments, UV–visible,IR, 1H and 13C NMRofpoly(3,4-ethylenedioxythiophene)(PEDOT)andits fluorine derivatives—Cn and [6,6] phenylCn butyric acidmethylesters(PCnBMs) bulk heterojunction (BHJ)solarcellsareinvestigatedbyusingdensityfunctionaltheory(DFT)and time-dependant densityfunctionaltheory(TD-DFT)calculations.Weaimtooptimizethe performance ofthesesolarcellsbyalteringthefrontierorbitalenergygapsofpolymersand fullerenes. Thiswasdonebyfunctionalizingthepolymersbackboneswithelectronwithdrawing fluorines step-bystep,andbyaddingphenylbutyricacidmethylestertothebuckminsterC60 and C70 fullerenes. Thetheoreticaldatawerecomparedwiththeavailableexperimentaldata. Based onthestrategyofreducingthebandgaps,thetrifluoroderivativeofPEDOT–buckminster C70 fullerene blend(outof24blends)wasfoundtobethebestcandidateforpowerconversion efficiency (PCE).Theadditionoffluorineatomstothepolymerbackboneiseffectivein lowering bothHOMOsandLUMOs.Conformationalanalysisconfirmsthatthecoplanarproper- tyof thiophenepolymersarenotdestroyedbytheincorporationoffluorineatoms.Whilestrong localization ofHOMOsoccursonthePEDOTdonorsubunits,strongdelocaliztionofLUMOs occurs onthebridgesbetweenthesubunits,provingtheflowoftheelectrondensityalongthe polymer backbone.Thepolarizabilityterm bxxx and dipolemoment mx increase withincreasing the powerconversionefficiency.Theabsorptionbandthatcorrespondstothemaximum coefficient ofthePEDOTinvacuumismarginallyshiftedundertheeffectofincorporating fluorines. VibrationalanalysisshowsthatfunctionalizingPEDOTleadstoamoreconjugated polymer backboneandenhancesthechargetransfertoanacceptor.Thepowerconversion efficiency ofthesolarcellincreaseswithincreasingthechemicalshiftsoftheconstituentC,H, and Oatoms.