应用光伏学题库.docx

应用光伏学题库.docx

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应用光伏学题库

一、选择题（在下列每题的四个选项中，只有一个选项是符合试题要求的。

请把答案填入答题框中相应的题号下。

每小题1分，共10分）

二、填空题（本大题共10小题，每小题1分，共10分）

§0

1.★Photovoltaics（oftenabbreviatedasPV）isasimpleandelegantmethodofharnessingthesun'senergy.

2.★PVdevices（solarcells）areuniqueinthattheydirectlyconverttheincidentsolarradiationintoelectricity,withnonoise,pollutionormovingparts,makingthemrobust,reliableandlonglasting.

3.★Photovoltaicsistheprocessofconvertingsunlightdirectlyintoelectricityusingsolarcells.

4.★Thefirstphotovoltaicdevicewasdemonstratedin1839byEdmondBecquerel,asayoung19yearoldworkinginhisfather’slaboratoryinFrance.

5.★Thefirstpracticalphotovoltaicdevicewasdemonstratedinthe1950s.

6.★★Researchanddevelopmentofphotovoltaicsreceiveditsfirstmajorboostfromthespaceindustryinthe1960s.

§1

1.★Aphotonischaracterizedbyeitherawavelength,denotedbyλ,orequivalentlyanenergy,denotedbyE.

2.★★Thereisaninverserelationshipbetweentheenergyofaphoton（E）andthewavelengthofthelight（λ）givenbytheequation:

，

.

3.★★Thephotonfluxisdefinedasthenumberofphotonspersecondperunitarea.

4.★★★Thetotalpowerdensityemittedfromalightsourcecanbecalculatedbyintegratingthespectralirradianceoverallwavelengthsorenergiesofinterest.

5.★★Intheanalysisofsolarcells,thephotonfluxisoftenneededaswellasthespectralirradiance.

6.★Theblackbodysourceswhichareofinteresttophotovoltaics,emitlightinthevisibleregion.

7.★★★ThespectralirradiancefromablackbodyisgivenbyPlank'sradiationlaw.

8.★★Thepeakwavelengthofthespectralirradianceisdeterminedbydifferentiatingthespectralirradianceandsolvingthederivativewhenitequals0.TheresultisknownasWien‘sLaw:

.

9.★★★Solarradiationinspace:

.Hsun=5.961×107W/m2.

10.★Thesolarradiationoutsidetheearth'satmospherehavebeendefinedasastandardvaluecalledairmasszero（AM0）andtakesavalueof1.353kW/m2.

11.★Thespectralirradiancefromablackbodyat6000K（atthesameapparentdiameterasthesunwhenviewedfromearth）;fromthesun’sphotosphereasobservedjustoutsideearth’satmosphere（AM0）;andfromthesun’sphotosphereafterhavingpassedthrough1.5timesthethicknessofearth’satmosphere（AM1.5G）.

12.★★TheAirMassisdefinedas:

.whereθistheanglefromthevertical（zenithangle）.

13.★★Whenthesunisdirectlyoverhead,theAirMassis1.

14.★ThestandardspectrumattheEarth'ssurfaceiscalledAM1.5G（theGstandsforglobalandincludesbothdirectanddiffuseradiation）orAM1.5D（whichincludesdirectradiationonly）,thesecalculationsgiveapproximately970W/m2forAM1.5G。

15.★ThestandardAM1.5Gspectrumhasbeennormalizedtogive1kW/m2duetotheconvenienceoftheroundnumberandthefactthatthereareinherentlyvariationsinincidentsolarradiation.

16.★ThestandardspectrumoutsidetheEarth'satmosphereiscalledAM0,becauseatnostagedoesthelightpassthroughtheatmosphere.

17.★ThestandardAM0spectrumistypicallyusedtopredicttheexpectedperformanceofcellsinspace.

18.★★★Wavelengthsbelow0.3μmarestronglyabsorbedbyozone.Theabsorptionbandsaround1μmareproducedbywatervaporabsorption,complementedbyCO2absorptionatlongerwavelengths.

19.★★★TheairmassrepresentstheproportionofatmospherethatthelightmustpassthroughbeforestrikingtheEarthrelativetoitsoverheadpathlength.

20.★★Diffuseradiationispredominantlyattheblueendofthespectrumbecauseofmoreeffectivescatteringatsmallwavelengths.Hence,theskyappearsblue.

21.★★AM1radiation（radiationwhenthesunisdirectlyoverhead）,hasadiffusecomponentofabout10%whenskiesareclear.

22.★★★Carbondioxideabsorbsstronglyinthe13-19μmwavelengthbandandwatervapour,anotheratmosphericgas,absorbsstronglyinthe4-7μmwavelengthband.Mostoutgoingradiation（70%）escapesinthe“window”between7-13μm.

23.★★Thetwocommonmethodswhichcharacterizesolarradiationarethesolarradiance（orradiation）andsolarinsolation.

24.★★Whilesolarirradianceismostcommonlymeasured,amorecommonformofradiationdatausedinsystemdesignisthesolarinsolation.

25.★ThesolarradianceisaninstantaneouspowerdensityinunitsofkW/m2.

26.★★Thesolarinsolationisthetotalamountofsolarenergyreceivedataparticularlocationduringaspecifiedtimeperiod,ofteninunitsofkWh/（m2day）,alsoinunitsofMJ/m2peryear.

27.★★TheaveragedailysolarinsolationinunitsofkWh/m2perdayissometimesreferredtoas“peaksunhours”.Forexample,alocationthatreceives8kWh/m2perdaycanbesaidtohavereceived8hoursofsunperdayat1kW/m2.

28.★Thedeclinationofthesunistheanglebetweentheequatorandalinedrawnfromthecentreoftheearthtothecentreofthesun.

29.★★★Thedeclinationofthesuniszeroattheequinoxes（March22andSeptember22）,positiveduringthenorthernhemispheresummerandnegativeduringthenorthernhemispherewinter.

30.★★★Theelevationoraltitudeangleistheangularheightofthesunintheskymeasuredfromthehorizontal.Theelevationis0°atsunriseand90°whenthesunisdirectlyoverhead.

31.★★Thezenithangleissimilartotheelevationanglebutitismeasuredfromtheverticalratherthanfromthehorizontal.

32.★★★TheazimuthangleisthecompassdirectionfromwhichthesunlightiscomingwithNorth=0°,South=180°,90°atsunriseand270°atsunset.

33.★★Forafixedtiltangle,themaximumpoweroverthecourseofayearisobtainedwhenthetiltangleisequaltothelatitudeofthelocation.

34.★Themoduleisorientatedtotheequatorsoitfacesnorthinthesouthernhemisphereandsouthinthenorthernhemisphere.

35.★★Thesunisatanaltitudeof30°tothehorizontal,thecorrespondingairmassis2.

36.★★Thelengthoftheshadowcastbyaverticalpostwithaheightof1munderAM1.5illuminationis.

§2

1.★★Themostimportantparametersofasemiconductormaterialforsolarcelloperationare:

（1）thebandgap;

（2）thenumberoffreecarriersavailableforconduction;（3）thegenerationandrecombinationoffreecarriersinresponsetolightshiningonthematerial.

2.★Theelectricalpropertiesofsemiconductorscanbeexplainedusingtwomodels,thebondandthebandmodels.

3.★★Thebandmodeldescribessemiconductorbehaviorintermsoftheenergylevelbetweenvalenceandconductionbands.

4.★★Thelowerenergylevelofasemiconductoriscalledthe"valenceband"（EV）andtheenergylevelatwhichanelectroncanbeconsideredfreeiscalledthe"conductionband"（EC）.Thebandgap（EG）isthedistancebetweentheconductionbandandvalenceband.

5.★Thebandgapcorrespondstotheminimumenergyneededtoreleaseanelectronfromavalencebondtotheconductionbandwhereitcanconductacurrent.

6.★★★Boththeelectronandholecanparticipateinconductionandarecalled"carriers".

7.★★Itispossibletoshiftthebalanceofelectronsandholesinasiliconcrystallatticeby"doping"itwithotheratoms.

8.★★Atomswithonemorevalenceelectronthansiliconareusedtoproduce"n-type"semiconductormaterial,whichaddselectronstotheconductionbandandhenceincreasesthenumberofelectrons.

9.★★★Inp-typematerial,thenumberofelectronstrappedinbondsishigher,thuseffectivelyincreasingthenumberofholes.

10.★★Indopedmaterial,thereisalwaysmoreofonetypeofcarrierthantheotherandthetypeofcarrierwiththehigherconcentrationiscalleda"majoritycarrier",whilethelowerconcentrationcarrieriscalleda"minoritycarrier".

11.★★★Thenumberofcarriersintheconductionandvalencebandwithnoexternallyappliedbiasiscalledtheintrinsiccarrierconcentration.

12.★★★Formajoritycarriers,theequilibriumcarrierconcentrationisequaltotheintrinsiccarrierconcentrationplusthenumberoffreecarriersaddedbydopingthesemiconductor.

13.★★Siliconorothersemiconductormaterialsusedforsolarcellscanbesinglecrystalline,multicrystalline,polycrystallineoramorphous.

14.★★Terminologyforvarioustypesofcrystallinesilicon（c-Si）

Descriptor

Symbol

GrainSize

CommonGrowthTechniques

Singlecrystal

sc-Si

>10cm

Czochralski（CZ）floatzone（FZ）

Multicrystalline

mc-Si

1mm-10cm

Cast,sheet,ribbon

Polycrystalline

pc-Si

1μm-1mm

Chemical-vapordeposition

Microcrystalline

c-Si

<1μm

Plasmadeposition

15.★★★Ithasbeenfoundthattheincorporationofatomichydrogeninamorphoussilicon,toalevelof5–10%,saturatesthedanglingbondsandimprovesthequalityofthematerial.

16.★★Theminoritycarrierdiffusionlengthsinthesilicon-hydrogenalloys（a-Si:

H）aremuchlessthan1μm.

17.★★Photonsincidentonthesurfaceofasemiconductorwillbeeitherreflectedfromthetopsurface,willbeabsorbedinthematerialor,failingeitheroftheabovetwoprocesses,willbetransmittedthroughthematerial.

18.★Forphotovoltaicdevices,reflectionandtransmissionaretypicallyconsideredlossmechanismsasphotonswhicharenotabsorbeddonotgeneratepower.

19.★★★Ifthephotonisabsorbeditwillraiseanelectronfromthevalencebandtotheconductionband.

20.★Theabsorptiondepthisausefulparameterwhichgivesthedistanceintothematerialatwhichthelightdropstoabout36%ofitsoriginalintensity,oralternatelyhasdroppedbyafactorof1/e.

21.★★Neglectingreflection,theamountoflightwhichisabsorbedbyamaterialdependsontheabsorptioncoefficientandthethicknessoftheabsorbingmaterial.

22.★★★Assumingthatthelossinlightintensity（i.e.,theabsorptionofphotons）directlycausesthegenerationofa