钙钛矿文献综述

NATURENANOTECHNOLOGY|VOL10|MAY2015|–inorganichybridcompounds,havesprungtotheforefrontofphotovoltaicresearchactivity3–6.ThesematerialsarecrystallizedfromorganichalideandmetalhalidesaltstoformcrystalsintheABX3structure,whereAistheorganiccation,BisthemetalcationandXisthehalideanion(Fig. 1a).Thepowerconversionefficiencyofperovskitesolarcellshasriseninjustfouryearsfromabout3%toover20%(theseval-ueswereindependentlycertified),withsignificantimprovementsoccurringafter20127–11.Moreover,severaldevicearchitectureshavebeentested,andthematerialhasproventoberemarkablyversatiletomanufacturingmethods.Unlikeinthe1950s,thousandsofresearchersarenowadaysinvolvedworldwideinthedevelopmentofphotovoltaicdevices,andalargefractionofthecommunityhasturnedtheirattentiontowardsperovskitesolarcells.Theseworldwideeffortsandtheexcellentmaterialpropertiesmighteventuallyleadtoachallengetothe60-yearreignofthecrystallinesiliconsolarcells.Thereexistcomprehensivediscussionsofthe(short)historicalevolutionoftheperovskitesolarcells3–6,12.ThisReviewwillnotrepeatthatnarra-tive,butratherwilldelveintothedifferentaspectsthatgovernthefabrication,operationandstabilityofthesedevices.Closelyfollow-ingthesolarcelldevelopment,thelight-emittingpropertiesofper-ovskitesemiconductorshavebeenreinvigoratedandherewealsoreviewrecentprogressinutilizingorganic–inorganicperovskitesinlight-emittingdevicesandlasers.MethodsfordepositingCH3NH3PbX3Thefirstembodimentsofthesolarcellsweredemonstratedbymix-ingastoichiometric(1:1)molarratioofCH3NH3I(methylammo-niumiodide,MAI)withPbI2inaγ-butyrolactonesolution7,13.ThisMetal-halideperovskitesforphotovoltaicandlight-emittingdevicesSamuelD.StranksandHenryJ.Snaith*Metal-halideperovskitesarecrystallinematerialsoriginallydevelopedoutofscientificcuriosity.Unexpectedly,solarcellsincorporatingtheseperovskitesarerapidlyemergingasseriouscontenderstorivaltheleadingphotovoltaictechnologies.Powerconversionefficiencieshavejumpedfrom3%toover20%injustfouryearsofacademicresearch.Here,wereviewtherapidprogressinperovskitesolarcells,aswellastheirpromisinguseinlight-emittingdevices.Inparticular,wedescribethebroadtunabilityandfabricationmethodsofthesematerials,thecurrentunderstandingoftheoperationofstate-of-the-artsolarcellsandwehighlightthepropertiesthathavedeliveredlight-emittingdiodesandlasers.Wediscusskeythermalandoperationalstabilitychallengesfacingperovskites,andgiveanoutlookoffutureresearchavenuesthatmightbringperovskitetechnologytocommercialization.solutionwascoatedontopofmesoporousTiO2resultingintheformationofsmallMAPbI3orMAPbBr3perovskitenanoparticlesendowingthesurface(Fig. 1b).Typicalparametersthatcantunethefilmformationinclude:precursorsolutionsolventandcomposi-tion(bothconcentrationandstoichiometry),andthetemperatureandtimeoffilmdryingandcrystallization14,15.Byincreasingthesolutionconcentration,andcoatingonthinnermesoporousTiO2films,polycrystallineperovskitefilmscanbeformed,whichformsolid,continuouslayerswithinandontopofamesoporousTiO2(orAl2O3)film(Fig. 1c)15–18.Bytuningthecompositionofthepre-cursorsolutionandincreasingtheorganicfraction,smoothersolidthinfilmswithcrystallinedomainsmanytimeslargerthanthefilmthicknesscanbemanufactured14,19.Figure 1dshowsafilmwithcrys-tallineplateletsoftensofmicrometresinsize(andafewhundredsofnanometresinthickness).Byincreasingthetemperatureofthecasting,andchoosingtheappropriatecomposition,crystalgrainsofmillimetrescalecanbeachieved(Fig. 1j)20.Ifsemi-transparencyisdesired,thecoverageoftheperovskitefilmscanbevariedfromcom-pletecontinuoustothecreationofislandsofperovskitesurroundedbyvoids(Fig. 1e).Thehighestefficienciesreportedrecentlyhavebeenachievedbyemployingsolvent-andinterface-engineeringtechniques10,21–23.Spin-coatingmixedsolventprecursorsolutionscontainingγ-butyrolactoneanddimethylsulphoxide(DMSO),followedbyquenchingwithanon-solvent,ledtoextremelyuniformanddenseperovskitelayersviaamethylammonium(MA)I–PbI2–DMSO,orformamidinium(FA)I/Br–PbI2–DMSO,intermediatephase,andacertifiedefficiencyof17.9%wasreported10,21.Itislikelythatarelatedapproachhasbeentakenfordevicesyieldingacertifiedefficiencyof20.1%11.IthasalsobeendemonstratedthatthedepositionofMAPbI3–xClxperovskitefilmsthroughanenhanced‘reconstruction’processincontrolled(30%)humidityconditionsleadstofilmswithsignificantlyreducedcarrierrecombination22.Althoughcontrolledhumiditycanenhancethepropertiesoftheperovskite24,25,moistureisnotablydetrimentaltolong-termstability,whichwillbedi