Triple-Junction GaAs Solar Cells: Duba Cikakke kan Tsarin Hasken Rana na Sararin Samaniya
Teburin Abubuwan Ciki
Gabatarwa
Yayin da kasuwancin sararin samaniya ke ci gaba da girma, jiragen sama suna buƙatar ƙarin wutar lantarki. Photovoltaics na sararin samaniya sune babban tushen wutar lantarki ga yawancin jiragen sama, don haka zaɓin fasahar sel hasken rana kai tsaye yana tsara ko aikin ya yi nasara, yadda yake da tsada, da kuma yadda yake ci gaba da kasancewa a kasuwa.
A yanzu, akwai manyan hanyoyin fasaha guda uku: gallium arsenide (GaAs), p-type heterojunction (HJT), da p-type HJT/perovskite tandem cells. Idan muka kalli inda fasahar ke tafiya da kuma yuwuwarta na dogon lokaci, kuma muka zurfafa bincike kan mahimman fa'idodi da rashin fa'idodin kowace hanya, GaAs har yanzu ita ce ta fi kyau. Duk da kalubalen farashi, aikin da ba a iya kwatanta shi ba, amincin da aka tabbatar a wurare masu tsananin yanayi, da kuma sarari mai yawa na rage farashi, sun sa GaAs ta zama mafi kyawun zaɓi don ayyukan sararin samaniya na kasuwanci masu daraja da aminci a yau da kuma cikin shekaru 3-5 masu zuwa.
Fa'idodin GaAs Cells masu Junction Uku
Babban inganci
Bandgap na GaAs (1.42 eV) yana cikin mafi kyawun kewayon ka'ida. Bugu da ƙari, sel masu junction da yawa suna tara yadudduka na GaInP, GaAs, da Ge waɗanda ke ɗaukar photons masu ƙarfi, matsakaici, da ƙarancin kuzari bi da bi, wanda ke faɗaɗa bakan da za su iya amfani da shi sosai. Sabbin sel GaAs masu junction uku na sararin samaniya yanzu sun kai ingancin canza wutar lantarki sama da 30%.
Babban aminci
Ƙarfin juriya na radiation da kwanciyar hankali mai zafi mai kyau sun sa waɗannan sel su dace da ainihin buƙatun ayyuka masu daraja da tsawon rai. Fa'idar aikin ya isa ya biya farashi mafi girma.
Fasaha mai girma tare da dogon tarihin aiki a sararin samaniya
A shekarar 1965, tauraron dan adam Venera 3 na tsohuwar Tarayyar Soviet ya zama na farko da ya yi amfani da sel GaAs. A shekarar 1995, tauraron dan adam na sadarwa na farko na kasuwanci MEASAT ya yi amfani da GaAs mai haɗin gwiwa guda ɗaya a matsayin babban rukunin wutar lantarki, kuma tsarin ƙirar hasken rana ya gina cikakken bayanan da ke tabbatar da cewa sel GaAs na iya biyan buƙatun wutar lantarki na tsawon rayuwar jirgin sama. Daga nan, sel GaAs a hankali sun maye gurbin tsofaffin sel a matsayin tushen samar da wutar lantarki a kan jiragen sama, suna ci gaba daga haɗin gwiwa guda ɗaya zuwa haɗin gwiwa da yawa.
Me yasa aka tsara shi azaman Tsarin Haɗin Gwiwa Uku?
Kowane kayan semiconductor na iya ɗaukar photons masu ƙarfi fiye da bandgap ɗinsa yadda ya kamata. Photons masu ƙarancin ƙarfi ba za a iya amfani da su ba, yayin da photons masu yawan ƙarfi suna rasa rarar a matsayin zafi (asarar thermalization). Bandgap na sel mai haɗin gwiwa guda ɗaya ba zai iya daidaita da hasken rana ba. Misali, sel silicon mai haɗin gwiwa guda ɗaya: yana iya ɗaukar photons a cikin kewayon 0.3-1.1 μm (300 nm-1100 nm), yana aiki musamman a cikin band 0.38 μm-0.7 μm. Shi ya sa sel silicon mai haɗin gwiwa guda ɗaya ke da iyaka iyaka, tare da iyakar ka'idar kusan 29.7%.
Tantanin haɗin gwiwa uku yana raba aikin zuwa ƙananan tantanin halitta guda uku, yana yanke hasken rana zuwa sassa uku don kowane ƙaramin tantanin halitta yayi aiki a cikin mafi kyawun band ɗin sa. Wannan yana rage duka asarar thermalization da asarar rashin daidaituwa na bakan. A ka'ida, tantanin halitta masu haɗin gwiwa da yawa na iya kusan kusan 50% inganci, fiye da abin da tsarin haɗin gwiwa guda ɗaya zai iya bayarwa.
Tsarin Tantanin Halitta GaAs Mai Haɗin Gwiwa Uku
Tantanin halitta GaAs mai haɗin gwiwa uku an raba shi zuwa sassa uku: tantanin halitta na sama, tantanin halitta na tsakiya, da tantanin halitta na ƙasa. Kowane sashi yana amfani da kayan aiki daban-daban (yankin tushe) kuma yana taka rawa daban-daban.
Tantanin halitta na sama
Yawanci AlGaInP / GaInP, tare da bandgap kusan 1.8-1.9 eV. Yana ɗaukar photons masu gajeren zango (ultraviolet, haske shuɗi). Tantanin halitta na sama yana shanye photons masu ƙarfi kuma yana rage asarar thermalization.
Tantanin halitta na tsakiya
Yawanci InGaAs ko GaAs, tare da bandgap kusan 1.42 eV. Yana ɗaukar photons masu matsakaici da dogon zango (kore, rawaya, ja). Tantanin halitta na tsakiya yana ɗaukar tsaka-tsaki zuwa dogon zango kuma yana ba da mafi yawan photocurrent.
Tantanin halitta na ƙasa
Yawanci Ge, tare da bandgap kusan 0.67 eV. Yana ɗaukar haske mai tsayin raƙuman ruwa (infrared kusa). Tantanin ƙasa yana ɗaukar hasken infrared mai shiga sosai.
Yanzu bari mu bi abin da kowane Layer yake yi.
① Layer Tuntuɓar
Yana zaune a saman Layer Cap na waje, wannan shine Layer semiconductor wanda lantarki ke taɓa kai tsaye. Yawanci ana yi masa doping mai nauyi n⁺⁺-GaAs ko n⁺⁺-GaInP. Babban aikinsa shine rage juriyar tuntuɓar—doping mai nauyi yana taimaka masa ya samar da kyakkyawar tuntuɓar ohmic tare da lantarki kuma yana rage asarar wutar lantarki. Hakanan yana kare yankin aiki, yana ware lantarki daga yankin aiki mai laushi a ƙasa (window layer, emitter, da sauransu) don hana lalacewa ta hanyar tsari.
② Layer Cap
Yana samuwa a saman layin taga kuma a ƙarƙashin rufin anti-reflection, yana tsakanin fim ɗin anti-reflection da layin lamba. Yawanci Gaasa ne, ko da yake wasu ƙira suna amfani da oxides masu gudanarwa na gani (TCO) kamar ITO. Babban aikinsa shine taimakawa tattara wutar lantarki a matsayin "electrode mai taimako," yana aiki tare da layin lamba don tattarawa da fitar da wutar lantarki a gefe—musamman mai amfani ga ƙirar grid mai layukan sirara. Ana iya daidaita kaurinsa da fihirisar refractive don shiga cikin ƙirar gani da kuma ba da tasirin anti-reflection na taimako.
③ Layin Taga
Yana samuwa a saman emitter, yawanci ana yinsa da AlInP, AlGaInP, ko AlGaAs. Babban aikinsa shine rage sake haɗuwa a saman: yanayin babban-bandgap na kayan yana nufin yana ɗaukar haske kaɗan, kuma yana samar da haɗin high-low wanda ke tura masu samar da haske (electrons) zuwa cikin emitter, yana yanke asarar sake haɗuwa a lahani na saman. Hakanan yana aiki azaman "laima," yana kare yankin haɗin daga lalacewa yayin ayyuka na gaba kamar evaporation na electrode.
④ Emitter
Yana ƙarƙashin layin taga kuma sama da tushe, yana samar da haɗin PN tare da tushe. Yawanci N-type GaInP ko GaAs ne. Babban aikinsa shine ya zama "electrode mai inganci," yana tattara electrons da aka samar da haske kuma ya kai su ga waje. Hakanan yana daidaita ɗaukar haske da tattarawa - ta hanyar daidaita kauri da yawan doping, yana da kauri don ɗaukar haske mai gajeren zango amma ba mai kauri ba har masu ɗauka su sake haɗuwa yayin yaduwa.
⑤ Tushe
Yana ƙarƙashin emitter kuma sama da Layer BSF, wannan shine babban jikin haɗin PN. Yawanci p-type GaInP ko AlGaInP ne. A matsayin babban yanki mai ɗaukar haske, shine "doki mai aiki" na saman tantanin halitta, yana ɗaukar mafi yawan haske mai gajeren zango (shuɗi da ultraviolet), yana samar da nau'i-nau'i na electron-hole da aka samar da haske, kuma yana jigilar ramukan da aka samar da haske zuwa Layer BSF na baya ko electrode.
⑥ Layer BSF (Filin Bayan Tushe)
Located below the base and above the tunnel junction, forming a high-low junction with the base on the back side. The material is usually a wide-bandgap p-AlGaInP, AlGaAs, and the like. Its main role is to suppress reverse carrier recombination: the BSF layer creates a "barrier" on the back of the base that stops photo-generated holes from being recombined as they diffuse toward the back electrode, thereby boosting voltage and efficiency.
⑦ Reflector
Located between the top cell and the middle cell, or between the middle cell and the bottom cell. It is a Distributed Bragg Reflector (DBR) grown from alternating high- and low-refractive-index materials, such as AlAs/AlGaAs or AlInP/AlGaInP. Its main job is to reflect back the medium-to-long-wavelength light that the top and middle cells haven't absorbed and is about to escape, allowing for a second absorption pass that lifts overall current and efficiency.
⑧ Tunnel Junction
Located between the sub-cells, made of heavily doped thin layers (such as n++GaAs / p++GaAs). Like a "quantum tunnel," it lets photo-generated carriers pass through efficiently while keeping each sub-cell electrically independent.
Tsarin tantanin halitta na tsakiya yayi kama da na saman, sai dai kayan aiki daban, don haka ba za mu sake maimaita shi a nan ba. A ƙasa mun taƙaita abin da ya bambanta game da tantanin halitta na ƙasa.
⑨ Buffer Layer
An sanya shi tsakanin tantanin halitta na ƙasa da na tsakiya, yana magance matsalar rashin daidaiton lattice. Lokacin da kayan tantanin halitta na ƙasa (kamar InGaAs) bai dace da madaidaicin lattice na kayan sama (kamar GaAs) ba, buffer layer yana amfani da tsarin "graded" ko "metamorphic lattice" don sakin damuwa a hankali da "kame" threading dislocations, yana kiyaye su daga yankin aiki na tantanin halitta na ƙasa kuma ta haka yana inganta aikin tantanin halitta.
⑩ Tushen Tantanin Halitta na Ƙasa
Ana samunsa a gefen "kauri" na haɗin PN na tantanin ƙasa. Yawanci substrate ne na Ge nau'in p. Babban aikinsa shine ɗaukar hasken infrared mai tsayin raƙuman ruwa, yana aiki a matsayin babban aiki don samar da masu ɗaukar hoto a cikin tantanin ƙasa.
Bayanai Kaɗan
A cikin alamomin nau'in P/N, N++/P++ da makamantansu suna nuna haske da nauyi doping. Tsarin tantanin halitta na GaAs mai haɗin uku da aka kwatanta a wannan labarin ya tsallake tsarin lantarki, tsarin anti-reflection layer, da makamantansu don sauƙi.
Manazarta:
Tantanin hasken rana mai haɗin gwiwa uku tare da mai nuna haske da hanyar kera shi - 2022-0804
Tantanin hasken rana mai haɗin gwiwa uku InGaP/InGaAs/Ge tare da tsarin hana haske micro-nano da hanyar kera shi - 2018-0425
Hanyar tantanin hasken rana mai haɗin gwiwa uku da tantanin hasken rana mai haɗin gwiwa uku - 2020-11-13
Ra'ayin Ooitech
Ooitech ta yi imani: tantanin GaAs mai haɗin gwiwa uku, ta hanyar yanke bakan hasken rana a cikin ƙananan sel guda uku, suna ba da inganci mai girma da amincin da aka tabbatar wanda ya sa su zama zaɓi na farko don ayyukan wutar lantarki na sararin samaniya masu daraja a yau.
