太陽能電池論文

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3、 weloff sc* ad pr omotng Ie al r oud . elpmet of peopl es perorma ci eet lat a-mplsmes, a_ ai ote lok at the fec ne- of sea pr ogress Ca es baand rural can” bot had e nvionme nt tsregt he a nd another l ook at the si evionmet imprlament momentof . l opme nt a present, de pedng onte poteta for sustai

4、 nabl e . lopme nt Lea- people t、. a boutare wrts and peope t oak about "Oul ook" s not watt he pefrma nce.4p.p. rmonne d to the sarig poit of te queston, ad rele d t qust ons point Ma n s the sm ofsociare atonshi ps W ca I not lev e te chchua nyngdu, hous ng.tulsm ad eeranmet, e nertini n

5、g ad eve ceai polt cal e cnomic cul ual ad scil e nvronme nt and s on. IDe t luma n nee is, al aB of ie lcmeito be ng Pepe crae fr thei -.iva,a nd cont nneen. m g tereu-of tecnnt uclon. Ccloru i t hetansormaton of tepepe of te -orl d,cmmuni，vitaiS i the ceai on ofma.Theeore , an, . e do, the sat ng

6、poit s huma, -ha ae pepe. Us seld u dewlpment, tece of -hi c s t o m-tthe nees if pe ople includig -viva nee dsemot ona lnne ds and -l-tal-t needs. It so. d be note d that pe opl e ae not maci nes not te saw of a objel, not t becnt.- d. Pe opl e ha - thei o- pesnaiy has is o n pesnal ，ha s is o - di

7、g niy Pesn i I >e d of cae， ounnedto unndesad neldtmee. I s .ad t ha in the、-ulua socie， peple pl ant" i、.s.l .ce，ma n s a a nimar, "he iforma1nsce，-eu.：2012-2013學(xué)年第 二學(xué)期 物電學(xué)院期末考試卷I物理前沿講座II；學(xué)號:7 姓名：陳永澤 班級：10級物理3班III4;成績：II:評語：（考試題目及要求）s one ofthe”ccl fomof vale sThe so dids rees tie obje

8、cve li ngs ae of novaue ad Ie vale of un.ea pespecve. Dfeet vaues, peoples be. a>， s,ways dHent. Pepeo_nted fcus onh - ava a. rea , nee. the br .aies masses as vale s Adee to e opeorbetid* s "mate Ie ecnomy more developme nt, mpove d i .a . cut ua pros” y, ad - ahapi er s deey conce nei t ha

9、 huma nveipment a. h - ava* deve opme nt of sc, a nd h a atonal uniid, ins_bd in the maerai Cvl .i cHIzai on a nd spiiua cvizat oveal a n.-et i f Sealst civonta hgher level Asowant tosee that person's vaue .ee you nee , aso is tomee Ienee - ad the cmmuiy Adee topeopeoriee、tostongy aive everycomm

10、uh member,serve othes, be-i al tie commu niy of peopl. T he sc d Oul ook ide s on there crd, inc - ig w toate a recd of aci ments how taupefrmace aI d son. Wa es wa kid of Outlook hee topeope ore ntd lok, s ontheprrmie of respeci ng the i nteess ad po-weof peI pl e ceat ng a popul a, mhe ats, sedy h

11、eat pefrmanneceaig、ve fr one olice, the be nei -" icheets, ado<eal cnstrcton of weloff sc* ad promoig Ie alr oud develpmet of peoples pefrmanne-cievmet -lat a ccmplsmets, take aI othe 10k at the feciene- of scil pr ogrss ca baand rua can” both had e nvrnme nt tsregt he a nd tae aothe l 00k a

12、t the si evio nment mpr lament momet-of d l opme nt a preent, de pedig onthe poteta forlusanal e d lopment LLa<epepe tolakboutae wrthlss and <e peope t o tak abou "Oulook" snot wat the pefrma nne.4. pepe resonne d to the sarig poit ofte _esin, ad re- d t qust ons point Ma ns the sm o

13、fsocilre ainshi ps W ca I not lev e te chchua nyngdu, housng,tu - m ad eeranmet, enertii ng ad eve ceai polt cal e cnomic cul ual ad scil e nvionme nt and s on. IDe t luma n nee is, al w als of ie wl cme ito be ng Pepe crae fr theiluviva,and cont nneen.oig tereulsof tecnntr ucton. Ccloru i t he tans

14、ormain of tepepe of te worl d,cmmuniyviaiy i the ceai onof ma. Thereore, any wkwe do, the sat ng poit s huma, wha ae pepe. Us seldu deelpment,tece of whic s t o mletthe nees if people includigluviva nee dsemot ona lnne ds and latalzt needs. It sou d be note d that pe opl e ae not maci nes not te sae

15、 of a objec, not t becnt.- d. Pe opl e ha - thei ow pesnaiy, has is ow n pesnal iy,ha s is ow dg nity Pesn i I>ed of cae y ounnedto unndesadneld1mee. I s .ad t ha in the、-ulua sociey peple pl ant" i i_s_l scey .a n s a a"" "he if0rmi11nsciey, reu.太陽能電池原理及發(fā)展摘要：人類面臨著有限常規(guī)能源和環(huán)境破壞嚴(yán)

16、重的雙重壓力，己經(jīng) 成為越來越值得關(guān)注的社會與環(huán)境問題。 近年來，光伏市場快速發(fā)展 并取得可喜的成就。本文介紹了太陽能電池的原理和發(fā)展，以及各類 新型太陽能電池，比較了各類太陽能電池的轉(zhuǎn)換效率和發(fā)展前景。 關(guān)鍵字：太陽能電池；原理；發(fā)展；前景1 .引言由于人類對可再生能源的不斷需求，促使人們致力于開發(fā)新型能源。太陽在 40min內(nèi) 照射到地球表面的能量可供全球目前能源消費(fèi)的速度使用1年，合理的利用好太陽能將是人類解決能源問題的長期發(fā)展戰(zhàn)略，是其中最受矚目的研究熱點(diǎn)之一。 本文介紹了太陽能電池的原理和發(fā)展，以及各類新型太陽能電池，比較了各類太陽能電池的轉(zhuǎn)換效率和發(fā)展前 景。2 .太陽能電池原理太

17、陽能電池，是一種能有效地吸收太陽輻射能，并使之轉(zhuǎn)變成電能的半導(dǎo)體器件，由于他們利用各種勢壘的光生伏特效應(yīng)，所以也稱為光伏電池，其核心是可釋放電子的半導(dǎo)體。 最常用的半導(dǎo)體材料是硅。地殼硅儲量豐富，可以說是取之不盡、用之不竭。當(dāng)太陽光照射到半導(dǎo)體表面，半導(dǎo)體內(nèi)部N區(qū)和P區(qū)中原子的價電子受到太陽光子的激發(fā)，通過光輻射獲取到超過禁帶寬度 Eg的能量，脫離共價健的束縛從價帶激 發(fā)到導(dǎo)帶，由此在半導(dǎo)體材料內(nèi)部產(chǎn)生 出很多處于非平衡狀態(tài)的電子空穴對。 這些被光激發(fā)的電子和空穴，或自由碰 撞，或在半導(dǎo)體中復(fù)合恢復(fù)到平衡狀態(tài)。 其中復(fù)合過程對外不呈現(xiàn)導(dǎo)電作用，屬 于太陽能電池能量自動損耗部分。光激 發(fā)載流子中

18、的少數(shù)載流子能運(yùn)動到P N結(jié)區(qū)，通過 P- N結(jié)對少數(shù)載流子的牽 引作用而漂移到對方區(qū)域，對外形成與 P N結(jié)勢壘電場方向相反的光生電場。 一旦接通外電路，即可有電能輸出。當(dāng)陰極基彳卜抗反射涂層 二前接觸面發(fā)發(fā)層陽極F?接觸面圖I太陽能電池工作原理把眾多這樣小的太陽能光伏電池單元通過串并聯(lián)的方式組合在一起，構(gòu)成光伏電池組件， 便anda nd manpower devel opme nt,and seeking,majorproblemaemand foster advais one ofthepra cticalformofvalue s.Theso-calledval uesrefers

19、tothe objective thi ngs are ofnovalueand thevalue offundamentalperspective.Differentvalues, people's behaviour, attitudes,ways aredifferent.People-orientedfocusonhuman value and reality,weneedthe br oade stmassesasvalue s.A dhereto pe ople -oriented val ues, ist omakethe economymoredevelopme nt,

20、improve democracy, cult uralprosperit y,and live a happi er;is deeply concer nedt hat huma n deve lopme ntand humanvalue s, devel opme nt of social a ndhuman developmentofrationalunified,insisted i nthe materialcivili zation,political civilizati on a ndspiritual civilizati on i nthe ov eralladvancem

21、ent ofSociali st civilizati on toa higher level.Alsowant tosee that person's value isnotonly meetyour needs,also istomeetthenee ds ofot hers andthe community.A dheret ope ople -or iented,to stronglyadvocateeverycommunitymember,serveothers,benefici altothe communityofpeople.T heso-calle d Outl oo

22、kattitude is onthe re cord, includingw ho, howto create arecordofachievements,howtoevaluateperformance, a nd so on.What values,what kindofOutlook.Adheretopeople-orie ntedOutlook,is on thepremiseofrespecti ng the i nterestsand powerofpeople,creati ng a popul ar,warmhe arts,steady heart performance,cr

23、eating"servefor one officer,the be nefitof"achievement s,and overallconstruction ofwell-offsociety and pr omoting theall-r ound developmentof peopl e's performa nce.Achi evement evaluati on i n bot heconomic a ccomplishments,take anotherlookattheeffectivenessofsocialpr ogress; cha nges

24、 in bot h ur ban a nd rural change; both harde nvironme nttostrengt hen a ndtake an otherl ook atthe softenvironmentimprovementmomentumofdevel opme ntat present, de pending onthe potentialforsustai nabl edevel opme nt. Leave people totalka bout"values"are worthlessand leave peoplet otalkab

25、out "Outl ook" is notwhatt heperforma nce.4. peopleresponde dtothe startingpoint ofthequestion,andreplied toquesti ons poi nt. Ma n isthe sumofsocial rel ationshi ps. Weca nnot leav ethe chichua nyongdu,housi ng,tourism andentertainment,e ntertaini ng,andeven certain politi cal,e conomic,c

26、ult uraland sociale nvironme nt, andso on. Due to huma n nee ds,allw alksoflifewillcomeintobei ng. People create fortheir survival,a nd conti nueenjoying theresultsoftheconstruction. Colrfulin t hetransformation ofthepeople oftheworl d,communityvitality in thecreation of man.Therefore , anywork wedo

27、, thestarti ng pointis human,whatare people.Us speed up development,thecore ofwhi chis t o meetthe needs ofpe ople, incl udi ng survivalnee ds,emoti ona lnee ds and se -actualizationne eds.It shoul d be note dthatpe opl e arenot machi nes, notthe slave ofan object, nottobecontrolle d.Pe opl e haveth

28、eir own personality,hasits ow n personal ity,has its owndig nity. Person in nee d ofcare,y ou needto understand, needtomeet.Itis saidt hat inthe "agriculturalsociety, peoplepl ant" in"industrial society, ma n isana nimal""the information society,return會在太陽能的作用下輸出功率足夠大的電能。制造太

29、陽能電池的半導(dǎo)體材料有合適禁帶寬度非常重要。不同禁帶寬度的半導(dǎo)體，只能吸取一部分波長的太陽光輻射能以產(chǎn)生電子空穴對，禁帶寬度越小，所吸收的太陽光譜的可利用部分就越大，而同時在太陽光譜峰值附近被浪費(fèi)的能量也就越大?？梢姡?只有選擇具有合適禁帶寬度的半導(dǎo)體材料，才能更有效地利用太陽光譜。由于直接遷移型半導(dǎo)體的光吸收效率比間接遷移型高，故最好是直接遷移型半導(dǎo)體。3. 太陽能電池的發(fā)展3.1 . 第一代太陽能電池1954 年，美國貝爾實(shí)驗(yàn)室研制出第一塊半導(dǎo)體太陽能電池，開始了利用太陽能發(fā)電的新紀(jì)元。由于太陽能電池價格昂貴，因此其發(fā)展緩慢，當(dāng)時主要用于航天科技工程。20 世紀(jì) 70 年代，由于石油危機(jī)，

30、使人們對于可再生能源的興趣越來越濃，太陽能電池也進(jìn)入了快速發(fā)展的階段。近幾年太陽電池市場以每年30%的速度遞增。目前，第一代太陽能電池約占太陽能電池產(chǎn)品市場的86% 。第一代太陽能電池基于硅晶片基礎(chǔ)之上，主要采用單晶體硅、多晶體硅及 GaAs為材料，轉(zhuǎn)換效率為11%15%單晶硅生長技術(shù)主要有直拉法和懸浮區(qū)熔法。直拉法是將硅材料在石英坩鍋中加熱熔化，使籽晶與硅液面接觸，向上提升以長出柱狀的晶棒。直拉法的研究方向是設(shè)法增大硅棒的直徑（目前硅棒的直徑已經(jīng)達(dá)到100150mm） ，用區(qū)熔法生長單晶硅技術(shù)是將區(qū)熔提純和制備單晶結(jié)合在一起，可以得到純度很高的單晶硅，但成本很高。目前，在所有太陽能電池中此種

31、硅片的效率是最高的，因此， 采用低成本的方式改進(jìn)區(qū)熔法生長太陽能電池用單晶硅也是目前的發(fā)展方向。為了進(jìn)一步提高太陽能電池效率，近年來大力發(fā)展高效化電池工藝，主要有發(fā)射極鈍化及背面局部擴(kuò)散工藝、埋柵工藝和雙層減反射膜工藝等。多晶硅材料生長主要運(yùn)用定向凝固法及澆鑄法工藝。定向凝固法是將硅材料在坩鍋中熔融后，使坩鍋形成由上而下逐漸下降的溫度場或從坩鍋底部通冷源以造成溫度梯度，使固液界面從坩鍋底部向上移動而形成晶體。澆鑄法是將熔化后的硅液倒入模具內(nèi)形成晶錠，鑄出的方形硅錠被切成方形硅片做成太陽電池。目前使用最廣泛的是澆鑄法，此法簡單，能耗低， 利于降低成本，但容易造成錯位、雜質(zhì)等缺陷，而導(dǎo)致光電轉(zhuǎn)換效

32、率低于單晶硅太陽能電池。由于多晶硅太陽電池存在雜質(zhì)問題，光電轉(zhuǎn)換效率比單晶硅電池低但成本有所降低。目前阻礙太陽能電池推廣應(yīng)用的最大障礙就是成本問題，為進(jìn)一步降低成本，基于薄膜技術(shù)的第二代太陽能電池登上了歷史舞臺。【 2】3.2 第二代太陽能電池第二代太陽能電池是基于薄膜技術(shù)之上的一種太陽能電池。在薄膜電池中，很薄的光電材料被鋪在襯底上，大大地減小了半導(dǎo)體材料的消耗（薄膜厚度僅1um） ，也容易形成批量生產(chǎn)（其單元面積為第一代太陽電池單元面積的100 倍） ，從而大大地降低了太陽能電池的成本。 薄膜太陽能電池材料主要有多晶硅、非晶硅、碲化鎘等。多晶硅薄膜太陽能電池技術(shù)較為成熟。ow,w e ar

33、ein apoliticalparticipatiquality ofyourprenew hi stori calstageof allon ba sed on conspir acy to a-roundconstructionofa wellsentati on,mai nlydepends onhow much wedhereto pe opl e-oriente-offsociety.drafteda documentred,will bearoundto pr omotecoor dinationDevelopmentevecog nize dbythe le adership,

34、howmanyare listents,great searchings.Theport, howmanyce modifiednotdogn-dept hdograndstah thindi ng ofcosmetic,toseeki ngofstyle,helpmassesshare,iselopment haestee people is notonly an is be come theparty's importantwdea,itis ajob requireme nt.Philosophythrougto the people -oor ientedt houg ht i

35、nthe work ofthe Office, must beclearworkobjectives. PartyOfficeinthe citythisyearremains:A dvancedcivilstrife, localbrand.The County(City)Party Committeeofficesand un its dire ctlyunder theOfficetooexcellence,pe ople -oriente drequire ments,strengthe nthe construction and ma nagementofthe Office tow

36、ards thework"a higher level".Investe e1.nking; re quirementsw e highlig ht pla ce feature s,putsuperiora ppr oachpolicy a nd locala ctualcombi ned up, put pr esentationoftheme thrust andmasse sof bythought bywants to combi ne d up;requirementsdrich ofconnotation.cond,the survey redecision

37、ag ood i dea,a n importa ntpartofa goodstaff.This year,tofocusaround industrialt ural structure,as one of the” ccl fomof vale sThe so did s rees tie objecve li ngs ae of novaue ad Ie vale of un. ea pespecve.Dfeetvaues, peoples be.a>， s,ways dHent. Pepeo_nted fcus onh - ava a. rea , nee. the br .a

38、ies masses as vale s A dee to e ope orbetid * s "mate Ie ecnomy more devel opme nt, mpove d i .a . cut ua pros” y, ad - ahapi er s deey conce nei t ha huma nveipme nt a. h - ava * deve opme nt of sc, and h a atonal uniid, ins_bd i n the maerai Cvl .i cHIzai on a nd spiiua cvizat ov eal a n.- et

39、 i f Seal st civ onta hgher level Asowant toseethat person's vaue .eeyounee,asoistomee Ienee - adthecmmuiyAdeetopeope oriee、to stongy aive everycommuh member,serveothes,be-i al tie commu niy of peopl. The sc d Oul ook ide s on there crd, inc - ig w to ate a recd of aci mentshowtau pefrmace a I d

40、 son. Wa es wa kid of Outlook hee topeopeore ntd lok, s ontheprrmieofrespeci ng the inteess ad po-we of pe I pl e ceat ng a popul a, mhe ats, sedy heat pefrma nneceaig、ve fr one olice, the be nei -" icheet s, ad o<eal cnstrct on of weloff sc* ad pr omoig Ie al r oud develpmet of pe oples pef

41、rma nne-ci evmet -lat accmplsmets, take aI othe 10k at the feciene-ofscil pr ogrss ca baandrua can” both had e nvrnme nt tsregt he a nd tae aothe l 00k at the si evio nment mpr lament momet-of d l opme nt a preent, de pedig onthe poteta for lusa nal e d lopme nt LLa<e pepe tolakboutae wrthlss and

42、 <e peopet o tak abou "Oul ook" s not wat t he pefrma nne.4. pepe resonne d to the sarig poit of te _esin, ad re- d t qust ons point Ma n s the sm ofsocilre ainshi ps W ca I not lev e te chchua nyngdu, hous ng,tu - m ad eeranmet, e nertii ng ad eveceai polt cal e cnomic cul ual ad scil

43、e nvionme nt and s on. IDe t luma n nee is, al w als of ie wl cme it o be ng Pepe crae fr thei luviva,a nd cont nneen.oig tereuls of tecnntr ucton. Ccloru i t he tansormain of te pepe of te worl d,cmmuniyviaiy i t he ceaion of ma. Thereore, any wk we do, the sat ng poit s huma, wha ae pepe. Us seld

44、u deelpment,tece of whic s t o mletthe nees if pe ople includig luviva nee dsemot ona lnne ds and latalzt needs.Itsoudbenoted that pe opl e ae not maci nes not te sae of a objec, not t becnt.- d. Pe opl e ha - thei ow pesnaiy, has is ow n pesnal iy,ha s is ow dg nity Pesn i I >e d of cae y ounned

45、to unndesad neld1mee. I s .ad t ha in the、-ulua sociey peple pl ant" i i_s_l scey .a n s a a "" "he if0rmi11nsciey,reu.目前，多晶硅薄膜生長技術(shù)主要有液相外延生長法、低壓化學(xué)氣相沉淀法、快熱化學(xué)氣相沉淀法、催化化學(xué)氣相沉淀法、等離子增強(qiáng)化學(xué)氣相沉淀法、超高真空化學(xué)氣相沉淀法、固相晶化法和區(qū)熔再結(jié)晶法等。薄膜電池在很大程度上解決了太陽能電池的成本問題， 但是效率很低。目前商用薄膜電池的光電轉(zhuǎn)換效率只有6%8%”。為了進(jìn)一步提高太陽能電池的光

46、電轉(zhuǎn)換效率，各國學(xué)者開始研究太陽能電池的效率極限和能量損失機(jī)理，并在此基礎(chǔ)上提出了第三代太陽能電池的概念。表1各種太陽能電池技柑康太陽跳池種類量雕換效率%優(yōu)點(diǎn)缺點(diǎn)單品優(yōu)轉(zhuǎn)解嬴技術(shù)成熟壽命長成本高長林、林毓,檄效聿雕魅腳品喊但也腦以“初始用112,8出定重量范工藝簡單、轉(zhuǎn)換費(fèi)率氤成本 依廉穩(wěn)定性總有拈岐率衰退 敏應(yīng)多晶硅雕16砒成林版觸較氤雕性好生戶工舞要雌馥的腳蜿(CGIS)19,510.6楠光岐率如拆、髏串* 院性蛇工藝斛制和前是域需有相殺時料精勉SftffiCdS/CuS 屯肌曲端也他165及5成械亂轉(zhuǎn)化麴高、易于大臊生 產(chǎn)3.3 .第三代太陽能電池太陽能轉(zhuǎn)換成電能的卡諾循環(huán)效率可以達(dá)到9

47、5%而目前標(biāo)準(zhǔn)太陽能電池的理論轉(zhuǎn)換效率上限為33% 這說明提高太陽能電池的效率還有很大的空間。為了進(jìn)一步提高太陽能電 池的轉(zhuǎn)換效率，新南威爾士大學(xué)對太陽能電池中能量損失機(jī)理進(jìn)行了研究。圖是太陽能電池能量損 失機(jī)理的示意圖。圖中為熱損 失，和為 PN結(jié)和接觸電壓 損失，為電子-空穴結(jié)合所造 成的損失。由圖可見，造成太陽能電 池的能量損失主要是熱損失，光 生載流子對能很快將能帶多余 的能量以熱的形式損失掉；另一主要的能量損失是由電子-空穴對的重新結(jié)合引起的；還圖2太陽能電池能量戰(zhàn)失機(jī)理使得光子的能量激發(fā)出的光生載流子沒有多余的能量可以有一部分能量損失是由 PN結(jié)和 接觸電壓損失引起的。 為減少熱

48、損失，可以設(shè)法讓通過太陽能電 池的光子能量剛剛大于能帶能量，損失。為減少電子-空穴結(jié)合所造成的損失， 可設(shè)法延長光生載流子的壽命，這可以通過消tomeet. It s sad t hat in the、-ulua society people pi ant"、,s.i society ma n s ana nima" "he fnsocey,r s one of the”ccl fomof valesThe so ues rees tie objecve li ngs ae of novaue ad Ie vale of fun. ea pespecve. Dff

49、eet vaues, peoples bei ur 一、“ent. Pepe.re.te ide s on lere crd, inCudig w I crae a recd ofaci mentshowipefrmacea I d s on. Wa es Waki. of Oilook Adhee Ipeope ore nid Oulok,s on Ieprrm ofrespci ng Ie i4, pepe ronne d to the rig poitof the quesin, ad r.- d to qusti ons point. Man s the sm ofsocne ains

50、hi ps W I not lev e the chChua nyngdu, hous ng,Iu - m ad .nmet, e nertii ng ad eved fcus on huma tie ad rraiy, nned the br .es mas - as .les Anteess ad po-we of peI pl e ceaI ng a popul a, mhe as, sedy heat perceai polIl e cnomi Lui url ad sca e n-onme nI and s on. IDe IA dhee I | e “ rmanne,luma n

51、neeope orettd ues s "m.e Ie ecnomy more d l ceaig "_ne forone olce, the be nei -" lche-etds, al w as of ie wl cme ito be ng Pepe crae otheiopme nt, m«o<eddmocac, cut ua proslei5, ad o - alcnlUrcIon ofweloffsc* ad prluviva, and conI nue enjoig Iereu - i h i ilt ht h. lt h . l.

52、ltf ilh. l t fI lifii z I ii l iiliztii it l ilzI i th . l .t f SiltilzI t -t tI tomoig Ie al roud develpmet of peoples pefrma nne-cievmet -laI accmplsmes, ale aI oIe lok at the elfc ne- of sca pr ogrss ca .g - baand rua can” boI had e nvrnme nt Isregt he a nd tae a oIe l ook at the si evronmet impr

53、lament mof Ie cnsI ucIon. Cru i t he tansormain of Iepepe of Ie worl d, cmmuniy v » i the ma.Theeore,any w. we do, the saI ng poit s h - a, wha aepepe. Us seldup dvelpmeI Ienees if pe opl* incl ud I g luviva nee ds emoI ona lnneds and - alizain neImee Ieent, de peeds. It sou d be note d that pe

54、nne - ad the cmmuniy Aedig onIe pote Ia for lusanal e d l I pmee ae not maci nes not Iesaw of a objec,dee t o pe ope orieed to 1110ngy Idvcae eveycommu. m - be,ve oIes, be-i al IIe commu. of peple T he sc- d I ooknI LLa- pepe i、. aboule,ae wrIlss and peope t oak abou "Oul ook" is not what

55、t he pefrma nne.I be cntr- d. Pe opl e ha - their ow pesnaiIy has is ow n pesnal iy, hhs is own dig niy Pesn id of cae y ounnedto unndesad neld疊層太陽電池的制備可以通過兩種方式得到。太陽電池，一個是高帶寬的，另一個則是低帶寬的,太酊電池能常下降圖3疊層太陽電池的機(jī)理能帶2（中網(wǎng)帝）能幫1I價電子帶）除不必要的缺陷來實(shí)現(xiàn)。減小PN結(jié)的接觸電壓損失，可以通過聚集太陽光，加大光子密度的方法來實(shí)現(xiàn)。基于以上分析，澳大利亞和美國分別提出了第三代太陽能電池的概念。

56、當(dāng)然，目前第三代太陽能電池主要還在進(jìn)行概念和簡單實(shí)驗(yàn)研究。第三代太陽能電池主要有前后重疊電池， 多能帶電池，熱太陽能電池，熱載流子電池，和沖擊離子化太陽能電池等。4 .第三代新型太陽能電池的介紹4.1. 疊層太陽能電池一種是機(jī)械堆疊法，先制備出兩個獨(dú)立的然后把高帶寬的堆疊在低帶寬的電池上面；另一種是一體化的方法，電池間通過隧道結(jié)串接。在多結(jié)疊層串 接太陽電池中，由于各分電池由 P-N結(jié)組成，如果直接串聯(lián)在一起， 則由于P-N結(jié)反偏而不導(dǎo)電，采用隧道結(jié)結(jié)構(gòu)可以解決這一問題。據(jù)分析，無限增加太陽電 池的層數(shù)，理論上可獲得的最高效 率為86.8%。4.2. 多能帶太陽能電池多能帶電池也稱為不純能帶電池，最簡單的就是3能帶電池，基本原理如圖 8所示。能帶1和能帶3是大塊結(jié)晶中的價電子帶和傳導(dǎo)帶，能帶2是人工制備的中間能帶。這樣， 高能量范圍內(nèi)的太陽光（hv >Ei3）引起能帶1和3間的轉(zhuǎn)移，而中間能量范圍的太陽光引 起能帶1和2以及能帶2和3間的轉(zhuǎn)移而被吸收，這是覆蓋更寬的太陽光譜的嘗試。因此, 和多結(jié)太陽電池的情形一樣，對削減短波長域的能量損失有較好的