Rashin ƙarfin zafin jiki da kuma yanayin LeTID a cikin n-Type Back-Contact Solar Cells

Gabatarwar Samfur

Ƙwayoyin rana na interdigitated back-contact (IBC) suna motsa duka tuntuɓar ƙarfe na polarity zuwa baya. Gaban ba ya ɗauke da inuwar layin grid, don haka fa'idodin gani na texturing da kuma rufin anti-reflection suna fitowa gabaɗaya. Tare da kyakkyawan rufewa da tsarin tuntuɓa, n-type IBC na iya kaiwa ga babban ƙarfin buɗe kewayawa da yawan halin yanzu.

Abin da ake ciniki da shi shine ƙarancin tsari da aka gina a cikin ƙira. Ƙananan masu ɗaukar haske da aka samar dole ne su yi tafiya a kwance a fadin tushe kafin emitter ɗin da ke baya ya tattara su. Aikin na'urar ya dogara sosai akan tsawon rayuwar girma da ingancin rufewar baya. Da zarar haɗuwar bayan baya ko zubewar tuntuɓa ta kunna ta hanyar zafi, ƙididdigar yawan halin yanzu na duhu J0 ya tashi fiye da kima, kuma Voc ya sha wahala.

Wannan shi ne ainihin wurin shigar wannan aikin. A kan tantanin IBC na n-type, an sanya shaidu guda uku a cikin yanayi guda na zafi don su kulle tare: auna J-V mai haske daga 25 zuwa 85°C, gwajin damuwa na LeTID da aka gudanar a ƙarƙashin rana ɗaya a 45 zuwa 85°C har zuwa mintuna 960, da kuma nazarin I-V mai duhu a kan wannan kewayon zafin jiki.

Tsarin Gwaji

Zane-zanen sashin giciye na tantanin IBC na n-type: tuntuɓar p+ emitter da n+ BSF masu haɗaɗɗiya a baya, ƙirar gaba da ARC.

Tantanin gwajin yana da yanki na 258.3 cm², kaurin wafer na 151 ± 6 μm, lokacin haɗaɗɗiya na baya na kusan 480 μm, da faɗin yatsun emitter da BSF na kusan 250 μm da 90 μm. Auna mai haske ya gudana a AM1.5G, 100 mW/cm². A kowane wurin zafin jiki, bayan daidaitawar zafi, an haɗa sakamakon dubawa biyar. Damuwar LeTID an auna shi kai tsaye a wurin zafin damuwa, ba tare da sanyaya tsakiyar gwaji ba, kuma an rubuta shi a tazarar ƙididdiga na 1, 2, 4, 8 mintuna da sauransu. Kowane siga an daidaita shi zuwa ƙimar sa ta farko, wanda ke raba ainihin yanayin lalacewa daga tasirin ƙididdigar zafin jiki na nan take.

Hankalin Zafin Jiki na Tsayayyen Yanayi

Daidaitaccen juyin halitta na zafin jiki na sigogi hudu dangane da darajojin 25°C nasu.

A 25°C tantanin halitta yana nuna Jsc kusan 38.6 mA/cm², Voc kusan 0.743 V, FF kusan 79%, da inganci kusan 22.7%. Dumama zuwa 85°C, Jsc yana tashi kusan 3% kawai (+0.0203 mA·cm⁻²·K⁻¹, kusan +0.05%/K). Voc yana faɗuwa a layi a −1.4 mV/K (kusan −0.2%/°C). Ingantacciyar faɗuwa kusan 9%, kuma FF da ƙyar ya motsa.

Ƙaramin karuwa na yanzu ya fito daga raguwar bandgap. A ƙarƙashin dangantakar Varshni gefen sha yana motsawa zuwa tsayin raƙuman ruwa, don haka photogeneration yana samun ɗan ƙara. Rushewar wutar lantarki mai sauri ya fito daga haɓakar juzu'i na J0(T), wanda ke tafiyar da maida hankali na ɗaukar hoto da ayyukan sake haɗuwa. Voc yana da girma tare da ln(Jsc/J0), don haka matsakaicin haɓakar J0 ya isa ya haifar da asarar da za a iya aunawa.

Wannan ƙididdigar zafin jiki yana zaune a cikin kewayon −1.3 zuwa −1.6 mV/K na kowa ga ingantattun na'urorin silicon crystalline. Yana nuna tantanin halitta mai iyakancewa maimakon juriya ko jigilar kaya. Bayan daidaitawa, matsayi yana bayyana a sarari: a 85°C Voc yana faɗuwa kusan 15%, inganci kusan 9%, FF yana tsayawa cikin ±1%, kuma Jsc a zahiri yana samun kusan 3%.

LeTID Dynamics

LeTID lalacewa kuzari.

Auna tsayayyen yanayi kawai ya amsa "yaya zafi." Gwajin damuwa na LeTID ya cika "yaya yake canzawa da lokaci." A 85°C, Voc yana faɗuwa da sauri a cikin mintuna 10 zuwa 30 na farko, sannan a hankali ya kusanci quasi-saturation. A ƙananan zafin jiki, raguwar yana da sauƙi sosai. Bayan mintuna 960, Voc ya faɗi zuwa kusan 0.69 V, Jsc yana tsayawa a cikin ±2% a duk lokacin, FF yana motsawa kaɗan, kuma babu sake haɓakawa da ke bayyana a cikin taga gwaji. Tun da an ɗauki ma'auni a zafin damuwa bayan daidaitawar thermal, raguwar ƙarfin lantarki na farko ya kamata a danganta shi da kunna lahani mai sauri maimakon ma'aunin thermal na wucin gadi. Tsayayyen Jsc yana nuna cewa samar da haske da cirewa na gajeren lokaci ba su shafa ba, don haka babban asarar ba ta iyakance ga samarwa ba. Marubutan kuma sun lura da iyakancewa: babu gwajin sarrafa duhu-anneal, don haka ba za a iya cire gudummawar tasirin thermal zalla ba.

Tabbatar da Yanayin Duhu

Halayen lantarki na duhu da hanyoyin zubewa: (a) J-V curves na duhu, (b) juriya na bambanci, (c) an cire shunt da juriya na jerin, (d) nazarin Arrhenius na shunt conductance yana ba da Ea ≈ 1.10 eV.

Duhun I-V yana tunkarar wannan matsala daga wajen yanayin haske. Ƙarfin gaba yana ƙaruwa sosai da zafin jiki. Matsakaicin ƙananan ƙarfi yana nuna juriyar shunt tana raguwa a fili, yayin da yankin babban ƙarfi ba ya canzawa sosai. Don haka, canjin juriya da zafin jiki ke haifarwa ya fi rinjayi ta hanyar kunnawar ɗigogi, ba ta lalacewar juriyar jerin ba. Ƙididdigar ideality tana tsaye a 1.05 zuwa 1.25, ma'ana haɗuwar yaduwa ta fi rinjaya, tare da yuwuwar gudummawar SRH a babban zafin jiki.

Binciken Arrhenius na ƙarfin shunt yana ba da madaidaicin layi na ln(1/Rsh) da 1/T (R² = 0.97), tare da ƙarfin kunnawa na 1.10 ± 0.08 eV. Wannan yayi daidai da bandgap na silicon (kusan 1.12 eV) kuma ya faɗa cikin kewayon LeTID da aka ruwaito na 0.8 zuwa 1.2 eV. Ƙarfin kunnawa mai girman bandgap galibi ana danganta shi da jagoranci ta hanyar lahani mai zurfi, amma ba za a iya ware gudummawar tattara yawan masu ɗaukar ciki ba. Don haka, yana goyan bayan halayen ɗigogi masu kunnawa da zafin jiki ba tare da tantance takamaiman nau'in lahani ba.

Tsarin Haɗin kai da Fadada Filin

Layoyin shaida guda uku sun haɗu zuwa tsarin ilimin al'amura guda ɗaya: J0(t, T) = J0,intr(T) + A·Ndef(t, T). A saman halin yanzu na saturation na asali, akwai gudummawar lahani da ke kunna ta zafi wanda ke canzawa da lokaci da zafin jiki. Wannan sai ya canza zuwa asarar ƙarfin lantarki ta hanyar Voc = (nkT/q)·ln(Jsc/(J0 + 1)). Ƙarfafa sake haɗuwa da kunna ɗigogi suna gudana a layi ɗaya a cikin wannan magana ɗaya. Matsakaicin ƙimar zafin jiki na tsayayyen yanayi, kuzarin LeTID, da juyin halittar ɗigogi na duhu duk an haɗa su wuri ɗaya. Tsarin bai gano ainihin lahani ba.

Ƙara zuwa aikin waje: ƙarƙashin haske mai ƙarfi, zafin sel na module sau da yawa yakan kasance a 50 zuwa 65°C. Yin amfani da −1.4 mV/K, 60°C dangane da 25°C yana nufin kusan 49 mV na asarar ƙarfin lantarki, kuma LeTID da zafi ya ƙara yana ƙara asarar da ta dogara da lokaci a kan haka. Sakamakon ya shafi sel ɗin da aka auna kawai. Ga TOPCon mai tuntuɓar baya da HJT mai tuntuɓar baya, suna zama kawai nuni na inganci: girman lalacewa, ƙarfin kunnawa, da kuzarin sake haɓaka sun dogara da tsarin tuntuɓar kariya na kowannensu, ingancin mu'amala, rarraba hydrogen, da kwanciyar hankali na zafi, kuma sun cancanci nazarin kwatance na musamman. Ga na'urori masu inganci masu tuntuɓar baya a yanayi masu zafi, ƙarfin ƙarfin lantarki da yawan makamashi na dogon lokaci a ƙarshe sun dogara da kwanciyar hankalin kariyar baya da sarrafa lahani.

Ra'ayin Ooitech

Abin da ya ba mu mamaki a nan shi ne yawan wannan asarar 49 mV na waje da ke zaune a gefen baya, inda passivation da ingancin tuntuɓar ke yin ko karya dogon lokaci Voc. A kan layin module labarin iri ɗaya ne: yadda kuka yanka, kuka haɗa, da kuka lulluɓe IBC cell yana yanke shawarar ko wannan kwanciyar hankali na baya zai tsira a filin. Da yake mun gina layukan turnkey don tsarin IBC da HPBC, muna ganin ƙarfin LeTID a matsayin matsalar tsari-da-kayan aiki kamar na cell. Ya cancanci bin tashar mu ta YouTube www.youtube.com/ooitech idan kuna son ganin yadda ake gina modules na back-contact a zahiri.