PerovskiteSolarCellsfortheGenerationofFuelsfromSunlightWangW.P.2016-10-20Logo

GeneralIntroductionOutline1Photovoltaic-DrivenWaterSplitting2CO2Reduction3DiscussionandPerspective41.GeneralIntroduction1.1EnergyDemand,GlobalWarming,andtheNeedforStorageEnergysupplyAirpollutionClimatechangeunbalanceddistributionWorldtotalenergyconsumption:15TW(2015)-->30TW(2050)Cleanandrenewableenergysources:SolarenergyStorage?Lithiumionbatteriesandsupercapacitors:ExpensiveChemicalsfuels:CarbohydrateSeries/DC–DCpowerconverterCO2reduction:fiveconventionalcells1.2AdvantagesofPerovskiteasLightHarvestersforSolarFuelGenerationOnlydevicesgeneratingsufficientVocfordrivingthecompletereactioncanachievenonzeroef?ciencies.Advantagesofperovskitelightharvesters:IntrinsichighVocandbandgaptunability2PerovskitePhotovoltaic(PV)2.1OneCell-DrivenWaterSplittingOnlylargebandgapoxidesshowefficiencieswithonecellEffcienciesareverylowHypotheticalsingle-PVphotoelectrolysisdeviceAstheopen-circuitvoltageofasingleperovskitesolarcellcanbelargerthan1.23V,itisconceivablethat,forasystemusingefficientelectrocatalyststominimizetheoverpotential,onecellcoulddriveoverallwatersplittingCH3NH3PbI3

(1.5eV)

,CH3NH3PbBr3(2.3eV)2.1OneCell-DrivenWaterSplittingVoc=1.5VPCE=10.4%Onecellwithhighopen-circuitvoltage2.1OneCell-DrivenWaterSplittingBasedonef?cientEarth-abundantelectrocatalystsreportedintheliterature,whichcanreach20mAcm?2currentdensityatavoltagelowerthan1.5VforoverallwatersplittingSolartohydrogenconversionef?ciency10%?<OR>2.2TwoinSeriesConnectedPerovskiteCellONECELLExtremelylowoverpotentialFuctuationinrealsunlightTWOCELLsThisisthe?rsttimethatef?ciencyover10%hasbeenachievedwithlow-costlightharvestersandEarth-abundantelectrocatalysts.STH:12.3%TheoreticalSTH:17.8%(1.5eV)2.3TwoAbsorberTandemsTWOCELLSDoubleilluminatedareaBandgap:Trade-offbetweentheCurrentandVoltageTwoAbsorberTandemsDespitegreatefforttowarddevelopingsuchtandems,thebestefficiencieshavereachedonlyaround1%

STH:0.91%2.3TwoAbsorberTandemsCombiningthephotoanodeandphotovoltaicwithaplatinumcathodeforhydrogenevolution,standaloneone-sunwatersplittingphotocurrentsofnearly2mAcm?2wereachieved,correspondingtoaSTHefficiencyofnearly2.4%Photoanode:Fe2O3mostwidelystudiedsuitablebandgapstabilitynaturalabundance2.3TwoAbsorberTandems