電荷傳輸理論

EquivalentCircuitModelReporter:XiaoliFangContentPrincipleofEISEquivalentcircuitmodelsStructureandoperationofthedyesolarcell

Operatingprincipleofthedyesolarcell

Themainback-reactionslimitingthephotocurrentare:(a)radiationlessrelaxationoftheexcitedstateofthedye(b)recombinationoftheelectronswiththeoxidized

dye(c)andwiththetri-iodideintheelectrolytePrincipleofEISConditions

result

1.

steadystateoperatingconditions(lightintensity,celltemperature,theoperatingpointalongitsIVcurve)2.

AsmallamplitudeharmonicAC

voltagemodulationVAC(ω,t)

issuperimposedontheDCvoltageofthecell

3.

measuredwhilescanningthemodulationfrequencyf=ω/2πoveracertainrangeJanne

Halme,Paula

Vahermaa,etal.Adv.Mater.,22,E210–E234(2023).Theintermediatefrequencysemicircle:therecombinationreactionandthechargeaccumulationattheTiO2/electrolyteinterface.Thus,themiddlesemicirclecanbeenlargedwiththeincreaseofRr(retardingtherecombinationreaction).ThebiggerthediameterofthemiddlefrequencysemicircleintheNyquistplots,theslighteristheelectronrecombinationatthedyedTiO2/electrolyteinterface.Thelastlowfrequency:theWarburgdiffusionoftheionsintheelectrolyte.Shi-WooRhee,WoosungKwon.KoreanJ.Chem.Eng.,28(7),1481-1494(2023).HuajunTian,LinhuaHu,etal.J.Mater.Chem.,2023.

Atveryhighfrequencies:currentwillflowthroughRsandthecapacitorsincircuitelements(2),(3)and(4).Thehighfrequencysemicircle:theparallelcombinationofRctandCCEattheelectrolyte/counterelectrodeinterface.Z1:impedancesrelatedtochargetransportatthePtcounterelectrodeinthehighfrequencyregion(103–105Hz)Z2:TiO2/dye/electrolyteinterfaceinthemiddle-frequencyregion(1–103Hz)Z3:Nernstiandiffusionwithintheelectrolyteinthelow-frequencyregion(2×10-2-1Hz)Rh:aresistanceinthehigh-frequencyrangeover106HzTCOR2：theresistanceofthediodeinaDSCR3：WarburgimpedanceRsh：ashuntresistance,estimatedtobe2kΩ/cm2LiyuanHan,NaokiKoide,etal.Appl.Phys.Lett.,84(13),2433-2435(2023).LiyuanHan,NaokiKoide,etal.Appl.Phys.Lett.,86,213501(2023).Rs=Rh+R1+R31-103(ω2):theTiO2/dye/electrolyteinterface(Z2)0.1

-1(ω3)Hz:theNernstiandiffusionintheelectrolyte(Z3)SangwookLee,JunHongNoh,etal.J.Phys.Chem.C,113,6878–6882(2023).Theresistanceelement(Rs)inthehighfrequencyregion(>106Hz)isrelatedtothesheetresistanceoftheTCOlayer103-105Hz(ω1):thechargetransportattheTiO2/conductinglayerorPt/electrolyteinterfaces(Z1)RTCO

:arethecharge-transferresistanceforthereductionoftri-iodideattheuncoveredpartoftheFTO

CTCO:thecorrespondingelectrolyticdouble-layercapactanceRCO:theresistanceattheFTO-TiO2contactCCO:theinterfacecapacitanceDX:extendeddistributedelement

interprettheimpedanceduetodiffusionofelectronsandholesandtheirrecombinationacrossthedye-sensitizedheterojunctionMingkuiWang,PeterChen,etal.ChemPhysChem10,290–299(2023).★Thedevice

basedonvolatileelectrolytebenefitsfromalongelectronlifetime,fast

electrondiffusioninTiO2

nanoparticlenetwork,and

longchargecarrierdiffusionlengthyieldingthebestphotovoltaicperformance.ImpedanceatTiO2photoelectrodeR1：Impedanceatthesubstrate/TiO2interfaceR2:ImpedancebetweenTiO2particles★differentpreparationmethodsofTiO2SachikoMatsushita,ChieNishiyama,etal.J.NewMat.Electrochem.Systems,14,xxx-xxx(2023).RB

:theresistance

ofthecellboundaries

CB

:the

capacitanceofthecellboundaries

ZTiO