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1、BetterSolarEnergySystems:MoreHeat,MoreLightSolarphotovoltaicthermalenergysystems,orPVTs,generatebothheatandelectricity,butuntilnowtheyhaven’tbeenverygoodattheheat-generatingpartcomparedtoastand-alonesolarthermalcollector.That’sbecausetheyoperateatlowtemperaturestocoolcrystallinesilic
2、onsolarcells,whichletsthesilicongeneratemoreelectricitybutisn’taveryefficientwaytogatherheat.That’saproblemofeconomics.Goodsolarhot-watersystemscanharvestmuchmoreenergythanasolar-electricsystematasubstantiallylowercost.Andit，salsoaspaceproblem：photovoltaiccellscantakeupallthespaceont
3、heroof,leavinglittleroomforthermalapplications.Inapairofstudies,JoshuaPearce,anassociateprofessorofmaterialsscienceandengineering,hasdevisedasolutionintheformofabetterPVTmadewithadifferentkindofsilicon.HisresearchcollaboratorsareKunalGirotrafromThinSiliconinCaliforniaandMichaelPathak
4、andStephenHarrisonfromQueen’sUniversity,Canada."Mostsolarpanelsaremadewithcrystallinesilicon，butyoucanalsomakesolarcellsoutofamorphoussilicon,commonlyknownasthin-filmsilicon.Theydon’tcreateasmuchelectricity,buttheyarelighter,flexible,andcheaper.And,becausetheyrequiremuchlesssilicon,t
5、heyhaveagreenerfootprint.Unfortunately，thin-filmsiliconsolarcellsarevulnerabletosomebad-newsphysicsintheformoftheStaebler-Wronskieffect.“Thatmeansthattheirefficiencydropswhenyouexposethemtolight—prettymuchtheworstpossibleeffectforasolarcell,”Pearceexplains，whichisoneofthereasonsthin-
6、filmsolarpanelsmakeuponlyasmallfractionofthemarket.However,PearceandhisteamfoundawaytoengineeraroundtheStaebler-Wronskieffectbyincorporatingthin-filmsiliconinanewtypeofPVT.Youdon’thavetocooldownthin-filmsilicontomakeitwork.Infact，Pearce’sgroupdiscoveredthatbyheatingittosolar-thermalo
7、peratingtemperatures，neartheboilingpointofwater,theycouldmakethickercellsthatlargelyovercametheStaebler-Wronskieffect.Whentheyappliedthethin-filmsilicondirectlytoasolarthermalenergycollector,theyalsofoundthatbybakingthecellonceaday，theyboostedthesolarcell’selectricalefficiencybyover1
8、0percent.“Li
