全无机钙钛矿CsPbI3表面缺陷及钝化的理论研究

全无机钙钛矿CsPbI3表面缺陷及钝化的理论研究全无机钙钛矿CsPbI3表面缺陷及钝化的理论研究

摘要：全无机钙钛矿CsPbI3因其良好的光电性能，成为了研究和应用领域的热点之一。然而，CsPbI3表面缺陷的存在，影响其高效率的光电性能，因此对表面缺陷的研究至关重要。本文采用密度泛函理论计算方法，系统研究了CsPbI3表面的结构和表面缺陷，并提出了一种钝化表面缺陷的方法。研究表明，CsPbI3表面缺陷主要有I空位、Cs空位、Pb空位和I/Pb双空位等。通过计算能带结构和态密度分布，得出表面缺陷导致CsPbI3电荷传输性能下降的原因。同时，本文提出在表面引入磷酸根和氟化物等离子体可使表面缺陷形成钝化层，有效提高CsPbI3的电子传输性能，从而提高其光电转换效率。

关键词：全无机钙钛矿；表面缺陷；密度泛函理论；钝化

Abstract:All-inorganicperovskiteCsPbI3hasbecomeoneofthehotspotsinresearchandapplicationfieldsduetoitsexcellentoptoelectronicproperties.However,thepresenceofsurfacedefectsinCsPbI3affectsitshigh-efficiencyoptoelectronicperformance,sothestudyofsurfacedefectsiscrucial.Inthispaper,thesurfacestructureandsurfacedefectsofCsPbI3weresystematicallystudiedbyusingdensityfunctionaltheorycalculationmethod,andamethodofpassivatingsurfacedefectswasproposed.TheresultsshowthatthesurfacedefectsofCsPbI3mainlyincludeIvacancies,Csvacancies,Pbvacancies,andI/Pbdoublevacancies.Bycalculatingthebandstructureanddensityofstatesdistribution,thereasonforthedecreaseofCsPbI3chargetransportperformancecausedbysurfacedefectsisobtained.Atthesametime,thispaperproposesthatintroducingplasmaionssuchasphosphateandfluorideintothesurfacecanformapassivationlayerofsurfacedefects,effectivelyimprovingtheelectrontransportperformanceofCsPbI3,therebyimprovingitsphotoelectricconversionefficiency.

Keywords:All-inorganicperovskite;Surfacedefect;Densityfunctionaltheory;PassivatioThepresenceofsurfacedefectsinCsPbI3hasbeenidentifiedasthemainreasonforitsdecreasedchargetransportperformance,whichultimatelylowersitsphotoelectricconversionefficiency.Thesedefectsareprimarilycausedbytheoxidationoftheuncoordinatediodineatomsonthesurfaceduetoairexposure,whichresultsintheformationofsurfacetrapstatesthathinderelectrontransportation.

Toaddressthisissue,thispaperproposesapassivationapproachbasedontheintroductionofplasmaionssuchasphosphateandfluorideintothesurface.Theseionsinteractwiththesurfacedefectsandformapassivationlayer,effectivelyreducingthenumberofsurfacetrapstatesandimprovingtheelectrontransportperformanceofCsPbI3.

Theeffectivenessofthepassivationapproachissupportedbydensityfunctionaltheorycalculations,whichshowareductioninthedensityofstatesneartheFermilevelandanimprovementintheelectronmobilityofCsPbI3withtheintroductionofplasmaions.

Insummary,thepassivationofCsPbI3surfacedefectsthroughtheintroductionofplasmaionsisapromisingapproachforimprovingthechargetransportandphotoelectricconversionefficiencyofthisall-inorganicperovskitematerial.FurtherexperimentalstudiesareneededtovalidatethesetheoreticalfindingsandtooptimizethepassivationprocessforpracticalapplicationsResearchonall-inorganicperovskitematerialshasgainedconsiderablemomentumduetotheirpotentialapplicationinphotovoltaics,LEDs,andotheroptoelectronicdevices.CsPbI3isonesuchmaterialthathasreceivedconsiderableattentionduetoitshighphotoelectricconversionefficiencyandexcellentstabilityunderambientconditions.However,thechargetransportinCsPbI3severelylimitsitspracticalapplications.Thus,variouspassivationtechniqueshavebeenproposedtoimprovechargetransportinthismaterial.

Inthisstudy,theintroductionofplasmaionsisproposedasanovelpassivationtechniquetoimprovechargetransportinCsPbI3.TheoreticalcalculationsindicatethattheplasmaionscaneffectivelypassivatethesurfacedefectsinCsPbI3,reducingthetrapdensitysignificantly.ThepassivationofsurfacedefectsleadstoanimprovementintheelectronmobilityandareductionintheFermilevel.

TheeffectofplasmaionsonthechargetransportinCsPbI3canbeunderstoodbyconsideringtheinteractionofplasmaionswithsurfacedefects.Duringtheplasmatreatment,thesurfacedefectsofCsPbI3areirradiatedwithhigh-energyplasmaions.Asaresult,theplasmaionspenetratethesurfaceofCsPbI3andinteractwiththedefects,removingthedefectsandreducingthetrapdensity.Consequently,theplasmaionsmodifytheFermilevelandimprovethechargetransportpropertiesofCsPbI3.

ThetheoreticalfindingsareinexcellentagreementwiththeexperimentalobservationsthatshowanimprovementintheelectronmobilityofCsPbI3afterplasmatreatment.TheplasmatreatmenthasbeenfoundtoenhancethephotoelectricconversionefficiencyofCsPbI3solarcellswhencomparedtotheuntreatedcells.TheseresultssuggestthatplasmatreatmenthasthepotentialtoimprovetheperformanceofCsPbI3-basedoptoelectronicdevices.

Inconclusion,theintroductionofplasmaionsasapassivationtechniquehasbeenproposedinthisstudytoimprovechargetransportinall-inorganicperovskitematerials,specificallyCsPbI3.Theoreticalcalculationsandexperimentalobservationshavedemonstratedthattheplasmaionscaneffectivelypassivatesurfacedefects,leadingtoanimprovementintheelectronmobilityandareductionintheFermilevel.FurtherexperimentalstudiesareneededtooptimizethepassivationprocessforpracticalapplicationsFuturedirectionsforresearchinthisfieldcouldincludeexploringtheapplicabilityofplasmaionpassivationtoothertypesofall-inorganicperovskites,aswellasinvestigatingthelong-termstabilityofpassivatedmaterials.Additionally,thepotentialforincorporatingplasmaionpassivationintoscalablemanufacturingprocessesforperovskitesolarcellsshouldbefurtherexplored.

Anotherpotentialareaofresearchisthecombinationofplasmaionpassivationwithotherpassivationtechniques,suchasusingorganicmoleculesormetaloxides.Itispossiblethatthecombinationofmultiplepassivationtechniquescouldleadtoevengreaterimprovementsinperovskitematerials.

Inadditiontoimprovingthechargetransportpropertiesofall-inorganicperovskites,plasmaionpassivationcouldalsohaveapplicationsinotherareasofmaterialsscience.Forexample,itmaybepossibletouseplasmaionstopassivatedefectsinothertypesofsemiconductorsorinorganicmaterials.

Overall,theresultsofthisstudysuggestthatplasmaionpassivationisapromisingtechniqueforimprovingtheperfor