Electrodes na graphene masu haske da kuma shimfiɗawa

Kayan aiki masu girma biyu, kamar graphene, suna da kyau ga aikace-aikacen semiconductor na al'ada da kuma sabbin aikace-aikacen lantarki masu sassauƙa. Duk da haka, ƙarfin graphene mai ƙarfi yana haifar da karyewa a ƙarancin ƙarfi, wanda hakan ke sa ya zama ƙalubale a yi amfani da kyawawan halayensa na lantarki a cikin kayan lantarki masu shimfiɗawa. Don ba da damar yin aiki mai kyau na masu sarrafa graphene masu haske dangane da matsin lamba, mun ƙirƙiri nanoscrolls na graphene a tsakanin layukan graphene da aka tara, waɗanda ake kira da graphene/graphene scrolls (MGGs). A ƙarƙashin matsin lamba, wasu gungura sun haɗu da sassan graphene da suka rarrabu don kiyaye hanyar sadarwa mai ratsawa wanda ke ba da damar kyakkyawan ƙarfin lantarki a manyan nau'ikan. MGGs masu layi uku da aka tallafa wa akan elastomers sun riƙe kashi 65% na ƙarfin lantarki na asali a nau'in 100%, wanda ke daidai da alkiblar kwararar yanzu, yayin da fina-finan graphene masu layi uku ba tare da nanoscrolls ba suka riƙe kashi 25% kawai na ƙarfin lantarki na farko. Wani transistor mai shimfiɗawa wanda aka ƙera ta amfani da MGGs a matsayin electrodes ya nuna watsawa daga >90% kuma ya riƙe kashi 60% na fitowar sa ta asali a cikin nau'in 120% (daidai da alkiblar jigilar caji). Waɗannan transistor masu shimfiɗawa da haske na duk-carbon za su iya ba da damar optoelectronics masu shimfiɗawa masu ƙwarewa.
Kayan lantarki masu haske da za a iya miƙewa wani fanni ne mai tasowa wanda ke da muhimman aikace-aikace a cikin tsarin biointegrated na zamani (1, 2) da kuma damar haɗawa da optoelectronics masu shimfiɗawa (3, 4) don samar da na'urori masu laushi da nuni masu kyau. Graphene yana nuna kyawawan halaye na kauri na atomic, babban bayyanawa, da kuma yawan watsawa, amma aiwatar da shi a cikin aikace-aikacen da za a iya miƙewa an hana shi ta hanyar yanayin fashewarsa a ƙananan nau'ikan. Cin nasara kan iyakokin injina na graphene na iya ba da damar sabbin ayyuka a cikin na'urori masu haske da za a iya miƙewa.
Abubuwan da ke tattare da graphene na musamman sun sa ya zama ɗan takara mai ƙarfi ga ƙarni na gaba na na'urorin lantarki masu haske (5, 6). Idan aka kwatanta da mafi yawan amfani da mai jagora mai haske, indium tin oxide [ITO; 100 ohms/sq (sq) a 90% bayyanawa], graphene mai layi ɗaya da aka haɓaka ta hanyar adana tururin sinadarai (CVD) yana da irin wannan haɗin juriya na takarda (125 ohms/sq) da bayyanawa (97.4%) (5). Bugu da ƙari, fina-finan graphene suna da sassauci na musamman idan aka kwatanta da ITO (7). Misali, akan wani abu mai filastik, ana iya riƙe tasirinsa ko da don lanƙwasa radius na lanƙwasa kamar 0.8 mm (8). Don ƙara haɓaka aikin lantarki a matsayin mai jagora mai sassauƙa mai haske, ayyukan da suka gabata sun ƙirƙiri kayan haɗin graphene tare da nanowires na azurfa ɗaya (1D) ko nanotubes na carbon (CNTs) (9–11). Bugu da ƙari, an yi amfani da graphene a matsayin lantarki don gauraye masu auna heterostructural semiconductors (kamar 2D bulk Si, 1D nanowires/nanotubes, da 0D quantum dige) (12), transistors masu sassauƙa, ƙwayoyin hasken rana, da diodes masu fitar da haske (LEDs) (13-23).
Duk da cewa graphene ya nuna sakamako mai kyau ga na'urorin lantarki masu sassauƙa, aikace-aikacensa a cikin na'urorin lantarki masu shimfiɗawa an iyakance shi ta hanyar halayen injiniyancinsa (17, 24, 25); graphene yana da tauri a cikin jirgin sama na 340 N/m da kuma tsarin Young na 0.5 TPa (26). Ƙarfin hanyar sadarwa ta carbon-carbon ba ya samar da wata hanyar watsar da makamashi don nau'in da aka yi amfani da shi don haka cikin sauƙi yana fashewa a ƙasa da nau'in 5%. Misali, CVD graphene da aka canza zuwa wani abu mai roba na polydimethylsiloxane (PDMS) zai iya kula da yanayinsa kawai a ƙasa da nau'in 6% (8). Lissafin ka'ida ya nuna cewa rugujewa da hulɗa tsakanin layuka daban-daban ya kamata su rage tauri sosai (26). Ta hanyar tara graphene a cikin layuka da yawa, an ruwaito cewa wannan graphene mai layi biyu ko uku yana iya shimfiɗawa zuwa nau'in 30%, yana nuna canjin juriya sau 13 ƙasa da na graphene mai layi ɗaya (27). Duk da haka, wannan ƙarfin shimfiɗawa har yanzu yana ƙasa da na zamani fiye da na'urorin sarrafawa masu shimfiɗawa na zamani (28, 29).
Transistors suna da mahimmanci a aikace-aikacen da za a iya shimfiɗawa domin suna ba da damar karanta firikwensin mai zurfi da nazarin sigina (30, 31). Transistors akan PDMS tare da graphene mai layi da yawa azaman tushen/magudanar da lantarki da kayan tashar na iya kiyaye aikin lantarki har zuwa kashi 5% na nau'in (32), wanda ya yi ƙasa da mafi ƙarancin ƙimar da ake buƙata (~50%) don na'urori masu sa ido kan lafiya da fata ta lantarki (33, 34). Kwanan nan, an bincika hanyar graphene kirigami, kuma transistor ɗin da aka sanya ta hanyar electrolyte mai ruwa za a iya miƙe shi har zuwa kashi 240% (35). Duk da haka, wannan hanyar tana buƙatar graphene da aka dakatar, wanda ke rikitar da tsarin ƙera.
A nan, muna samun na'urorin graphene masu shimfiɗawa sosai ta hanyar haɗa gungumen graphene (tsawon ~ 1 zuwa 20 μm, faɗin ~ 0.1 zuwa 1 μm, da tsayi ~ 10 zuwa 100 nm) a tsakanin layukan graphene. Mun yi hasashen cewa waɗannan gungumen graphene na iya samar da hanyoyin da za su iya haɗa tsagewa a cikin zanen graphene, don haka suna riƙe da babban ƙarfin lantarki a ƙarƙashin matsin lamba. Gungumen graphene ba sa buƙatar ƙarin haɗawa ko tsari; an samar da su ta halitta yayin aikin canja wurin danshi. Ta hanyar amfani da na'urorin lantarki masu shimfiɗa G/G (graphene/graphene) (MGGs) na graphene (source/drain and gate) da kuma na'urorin CNT masu sarrafawa, mun sami damar nuna transistors masu shimfiɗawa sosai kuma masu shimfiɗawa sosai, waɗanda za a iya miƙa su zuwa kashi 120% na nau'in (daidai da alkiblar jigilar caji) kuma su riƙe kashi 60% na fitowar su ta asali. Wannan shine transistor mai haske mai haske wanda aka gina a kan carbon zuwa yanzu, kuma yana samar da isasshen wutar lantarki don tuƙa LED mara tsari.
Domin samar da wutar lantarki mai haske mai faɗi a babban yanki, mun zaɓi graphene da aka girma a kan foil ɗin Cu. An rataye foil ɗin Cu a tsakiyar bututun quartz na CVD don ba da damar haɓakar graphene a ɓangarorin biyu, yana samar da tsarin G/Cu/G. Don canja wurin graphene, da farko mun yi amfani da wani siraran poly(methyl methacrylate) (PMMA) don kare gefe ɗaya na graphene, wanda muka sanya wa suna graphene na sama (wani gefen graphene), sannan daga baya, an jiƙa dukkan fim ɗin (PMMA/top graphene/Cu/bottom graphene) a cikin maganin (NH4)2S2O8 don cire foil ɗin Cu. Graphene na ƙasa ba tare da rufin PMMA ba zai yiwu ya sami tsagewa da lahani waɗanda ke ba da damar enchant ya ratsa ta (36, 37). Kamar yadda aka nuna a Hoto na 1A, a ƙarƙashin tasirin tashin hankali a saman, yankunan graphene da aka saki sun naɗe zuwa gungura sannan daga baya aka haɗa su akan sauran fim ɗin G/PMMA na sama. Ana iya canja wurin gungura na sama-G/G zuwa kowane substrate, kamar SiO2/Si, gilashi, ko polymer mai laushi. Maimaita wannan tsarin canja wuri sau da yawa akan substrate iri ɗaya yana ba tsarin MGG.
(A) Zane-zanen tsarin ƙera MGGs a matsayin lantarki mai shimfiɗawa. A lokacin canja wurin graphene, an karya graphene na baya akan foil ɗin Cu a kan iyakoki da lahani, an naɗe shi zuwa siffofi marasa tsari, kuma an haɗa shi sosai akan manyan fina-finai, yana samar da nanoscrolls. Zane na huɗu yana nuna tsarin MGG da aka tara. (B da C) Siffofin TEM masu ƙuduri mai girma na MGG mai layi ɗaya, suna mai da hankali kan graphene mai layi ɗaya (B) da yankin gungura (C), bi da bi. Shigarwar (B) hoto ne mai ƙarancin girma wanda ke nuna cikakken yanayin MGGs mai layi ɗaya akan grid ɗin TEM. Shigarwar (C) sune bayanan ƙarfin da aka ɗauka tare da akwatunan murabba'i da aka nuna a cikin hoton, inda nisan da ke tsakanin jiragen atomic shine 0.34 da 0.41 nm. (D) Bakan EEL na Carbon K-gefen tare da kololuwar graphite π* da σ* masu siffar graphite. (E) Hoton AFM na sashe na gungura G/G mai layi ɗaya tare da bayanin tsayi tare da layin rawaya mai dige-dige. (F zuwa I) Na'urar hangen nesa da hoton AFM na layin uku G ba tare da (F da H) ba kuma tare da gungura (G da I) akan ƙananan SiO2/Si masu kauri 300-nm, bi da bi. An yi wa gungura masu wakiltar da ƙuraje alama don nuna bambance-bambancensu.
Domin tabbatar da cewa gunguran suna da siffar graphene da aka yi birgima a cikin yanayi, mun gudanar da nazarin na'urar auna hasken lantarki mai ƙarfi (TEM) da kuma nazarin asarar makamashin lantarki (EEL) akan tsarin gunguran G/G na saman-layi. Hoto na 1B yana nuna tsarin hexagonal na graphene mai layi ɗaya, kuma shigarwar gabaɗaya yanayin fim ɗin da aka rufe a kan ramin carbon guda ɗaya na grid ɗin TEM. Graphene mai layi ɗaya yana yaɗuwa mafi yawan grid ɗin, kuma wasu flakes na graphene a gaban tarin zoben hexagonal da yawa sun bayyana (Hoto na 1B). Ta hanyar zuƙowa zuwa gungura ɗaya (Hoto na 1C), mun lura da adadi mai yawa na gefunan graphene, tare da tazarar lattice a cikin kewayon 0.34 zuwa 0.41 nm. Waɗannan ma'aunai suna nuna cewa flakes ɗin an naɗe su bazuwar kuma ba cikakke ba ne na graphite, wanda ke da tazarar lattice na 0.34 nm a cikin tarin layer na "ABAB". Siffa ta 1D tana nuna bakan carbon K-edge EEL, inda kololuwar da ke 285 eV ta samo asali ne daga π* orbital, ɗayan kuma a kusa da 290 eV ya samo asali ne daga canjin σ* orbital. Ana iya ganin cewa haɗin sp2 ya mamaye wannan tsari, yana tabbatar da cewa gungura suna da zane mai kyau.
Hotunan na'urar hangen nesa da kuma na'urar hangen nesa ta atomic force microscopy (AFM) suna ba da haske game da rarrabawar nanoscrolls na graphene a cikin MGGs (Hoto na 1, E zuwa G, da fig. S1 da S2). Ana rarraba gunguran bazuwar a saman, kuma yawansu a cikin jirgin sama yana ƙaruwa daidai gwargwado da adadin layukan da aka tara. Gunguran da yawa suna haɗuwa cikin ƙulli kuma suna nuna tsayi marasa tsari a cikin kewayon nm 10 zuwa 100. Suna da tsayin μm 1 zuwa 20 da faɗin 0.1 zuwa 1 μm, ya danganta da girman flakes na graphene na farko. Kamar yadda aka nuna a Hoto na 1 (H da I), gunguran suna da girma sosai fiye da wrinkles, wanda ke haifar da haɗuwa mai tsauri tsakanin layukan graphene.
Don auna halayen lantarki, mun tsara fina-finan graphene tare da tsarin gungurawa ko ba tare da su ba, kuma mun tattara layuka zuwa faɗin 300-μm da tsawon 2000-μm ta amfani da photolithography. An auna juriyar bincike biyu a matsayin aikin nau'in matsi a ƙarƙashin yanayin yanayi. Kasancewar gungurawa ya rage juriyar graphene mai layi ɗaya da kashi 80% tare da raguwar 2.2% kawai a cikin watsawa (hoto na S4). Wannan ya tabbatar da cewa nanoscrolls, waɗanda ke da yawan wutar lantarki mai yawa har zuwa 5 × 107 A/cm2 (38, 39), suna ba da gudummawa mai kyau ga MGGs. Daga cikin dukkan graphene mai layi ɗaya, bi-, da trilayer plain graphene da MGGs, trilayer MGG yana da mafi kyawun gudanarwa tare da bayyanawa kusan 90%. Don kwatantawa da sauran hanyoyin graphene da aka ruwaito a cikin wallafe-wallafen, mun kuma auna juriyar takardar bincike guda huɗu (hoto na S5) kuma muka lissafa su a matsayin aikin watsawa a 550 nm (hoto na S6) a cikin Hoto na 2A. MGG yana nuna daidaiton ko mafi girma da bayyanawa fiye da graphene mai launi da aka tara ta hanyar wucin gadi da kuma rage graphene oxide (RGO) (6, 8, 18). Lura cewa juriyar takardar graphene mai launi da aka tara ta hanyar wucin gadi daga adabi ya ɗan fi na MGG ɗinmu girma, wataƙila saboda yanayin girma da hanyar canja wurinsu mara kyau.
(A) Juriyar takardar bincike huɗu idan aka kwatanta da watsawa a 550 nm ga nau'ikan graphene da yawa, inda murabba'ai baƙi ke nuna mono-, bi-, da trilayer MGGs; da'irori ja da alwatika masu shuɗi suna daidai da graphene mai layi da yawa da aka girma akan Cu da Ni daga nazarin Li et al. (6) da Kim et al. (8), bi da bi, sannan aka canza su zuwa SiO2/Si ko quartz; kuma alwatika masu kore sune ƙima ga RGO a matakai daban-daban na raguwa daga nazarin Bonaccorso et al. (18). (B da C) Canjin juriya na mono-, bi- da trilayer MGGs da G a matsayin aikin perpendicular (B) da parallel (C) iri zuwa ga alkiblar kwararar yanzu. (D) Canjin juriya na bilayer G (ja) da MGG (baƙi) a ƙarƙashin nau'in cyclic da aka ɗora har zuwa 50% perpendicular iri. (E) Canjin juriya na trilayer G (ja) da MGG (baƙi) a ƙarƙashin nau'in cyclic da aka ɗora har zuwa 90% parallel iri. (F) Canjin ƙarfin da aka daidaita na mono-, bi- da trilayer G da bi- da trilayer MGGs a matsayin aikin n na nau'in. Inset ɗin shine tsarin capacitor, inda substrate ɗin polymer shine SEBS kuma polymer dielectric Layer shine SEBS mai kauri 2-μm.
Domin kimanta aikin MGG da ya dogara da matsin lamba, mun canja wurin graphene zuwa ga substrates na thermoplastic elastomer styrene-ethylene-butadiene-styrene (SEBS) (faɗin ~ 2 cm da tsawon ~ 5 cm), kuma an auna ƙarfin lantarki yayin da aka shimfiɗa substrate (duba Kayan Aiki da Hanyoyi) duka a tsaye da kuma daidai da alkiblar kwararar lantarki (Hoto na 2, B da C). Halin lantarki da ya dogara da matsin lamba ya inganta tare da haɗa nanoscrolls da ƙaruwar adadin layukan graphene. Misali, lokacin da matsin lamba ya daidaita da kwararar lantarki, ga graphene mai layi ɗaya, ƙarin gungura ya ƙara matsin lamba a lokacin karyewar lantarki daga 5 zuwa 70%. Haka kuma haƙurin ƙarfin lantarki na graphene mai layi ɗaya yana inganta sosai idan aka kwatanta da graphene mai layi ɗaya. Tare da nanoscrolls, a 100% perpendicular nau'in, juriyar tsarin MGG mai layi uku ya ƙaru da 50% kawai, idan aka kwatanta da 300% ga graphene mai layi uku ba tare da gungura ba. An binciki canjin juriya a ƙarƙashin nauyin matsin lamba na zagaye. Don kwatantawa (Hoto na 2D), juriyar fim ɗin graphene mai layi biyu ya ƙaru da kusan sau 7.5 bayan zagayowar ~700 a cikin nau'in perpendicular 50% kuma ya ci gaba da ƙaruwa tare da nau'in a kowane zagaye. A gefe guda kuma, juriyar MGG mai layi biyu ya ƙaru da kusan sau 2.5 kawai bayan zagayowar ~700. Idan aka yi amfani da nau'in har zuwa kashi 90% a kan alkiblar layi daya, juriyar graphene mai layi uku ya ƙaru ~ sau 100 bayan zagayowar 1000, yayin da yake ~ sau 8 kawai a cikin MGG mai layi uku (Hoto na 2E). Sakamakon zagaye an nuna shi a cikin hoto na S7. Ƙara juriya mai sauri a kan alkiblar nau'in layi daya shine saboda yanayin tsagewa yana daidai da alkiblar kwararar yanzu. Bambancin juriya yayin lodawa da sauke nauyin ya faru ne saboda dawo da viscoelastic na substrate na SEBS elastomer. Ƙarfin juriyar MGG yayin hawa keke ya fi ƙarfi saboda kasancewar manyan gungura waɗanda za su iya haɗa sassan graphene da suka fashe (kamar yadda AFM ta lura), suna taimakawa wajen kiyaye hanyar da ke ratsawa. An riga an ba da rahoton wannan lamari na kiyaye hanyar da ke ratsawa ta hanyar da ke ratsawa ga fasassun ƙarfe ko fina-finan semiconductor akan abubuwan da ke cikin elastomer (40, 41).
Domin kimanta waɗannan fina-finan da aka yi da graphene a matsayin electrodes na ƙofa a cikin na'urorin da za a iya shimfiɗawa, mun rufe layin graphene da layin SEBS dielectric (kauri 2 μm) kuma mun sa ido kan canjin ƙarfin dielectric a matsayin aikin nau'in (duba Hoto na 2F da Kayan Ƙarin Bayani don cikakkun bayanai). Mun lura cewa ƙarfin da ke da electrodes na monolayer da bilayer graphene sun ragu da sauri saboda asarar yanayin watsawa na graphene a cikin jirgin sama. Sabanin haka, ƙarfin da MGGs suka gina da kuma graphene mai layi uku sun nuna ƙaruwar ƙarfin da ke da nau'in, wanda ake sa ran saboda raguwar kauri na dielectric tare da nau'in. Ƙarar da ake tsammani a cikin ƙarfin ya yi daidai da tsarin MGG (hoto na S8). Wannan yana nuna cewa MGG ya dace a matsayin electrode na ƙofa don transistor masu shimfiɗawa.
Domin ƙarin bincike kan rawar da gungumen graphene na 1D ke takawa wajen jure wa matsin lamba na wutar lantarki da kuma yadda za a iya sarrafa rabuwa tsakanin layukan graphene, mun yi amfani da CNTs masu feshi don maye gurbin gungumen graphene (duba Ƙarin Kayan Aiki). Don yin kwaikwayon tsarin MGG, mun sanya yawan CNT guda uku (wato, CNT1).
(A zuwa C) Hotunan AFM na nau'ikan CNT guda uku daban-daban (CNT1)
Domin ƙara fahimtar iyawarsu a matsayin lantarki don na'urorin lantarki masu shimfiɗawa, mun bincika tsarin MGG da G-CNT-G a ƙarƙashin matsin lamba. Na'urar hangen nesa ta gani da na'urar hangen nesa ta electron (SEM) ba hanyoyin tantancewa masu tasiri ba ne saboda duka ba su da bambancin launi kuma SEM yana ƙarƙashin kayan tarihi na hoto yayin duban lantarki lokacin da graphene ke kan abubuwan polymer (figs. S9 da S10). Don lura a wurin da saman graphene ke ƙarƙashin matsin lamba, mun tattara ma'aunin AFM akan MGGs na layi uku da graphene mai sauƙi bayan sun canza zuwa kan siriri (~0.1 mm kauri) da kuma abubuwan SEBS na roba. Saboda lahani na ciki a cikin graphene na CVD da lalacewar waje yayin aiwatar da canja wurin, babu makawa ana haifar da tsagewa akan graphene mai tauri, kuma tare da ƙaruwar matsin lamba, tsagewar ta yi kauri (Fig. 4, A zuwa D). Dangane da tsarin tara na electrodes ɗin da ke tushen carbon, tsagewar suna nuna siffofi daban-daban (fig. S11) (27). Yawan yankin tsagewa (wanda aka ayyana a matsayin yankin tsagewa/yankin da aka yi nazari a kai) na graphene mai layuka da yawa bai kai na graphene mai layi daya ba bayan tauri, wanda ya yi daidai da karuwar wutar lantarki ga MGGs. A gefe guda kuma, ana lura da gungura don cike tsagewar, suna samar da ƙarin hanyoyin watsawa a cikin fim ɗin da aka taurara. Misali, kamar yadda aka yiwa alama a hoton Hoto na 4B, wani babban gungura ya ketare wani tsagewa a cikin MGG mai layi uku, amma ba a ga gungura a cikin graphene mai sauƙi ba (Hoto na 4, E zuwa H). Hakazalika, CNTs suma sun haɗu da tsagewar a cikin graphene (hoto na S11). An taƙaita yawan yankin tsagewa, yawan yankin gungurawa, da kuma rashin kyawun fina-finan a cikin Hoto na 4K.
(A zuwa H) Hotunan AFM na layin uku na G/G scrolls (A zuwa D) da tsarin layin uku na G (E zuwa H) akan siraran SEBS (kauri ~ 0.1 mm) a nau'in 0, 20, 60, da 100%. An nuna tsage-tsage da gungura masu wakiltar da kibiyoyi. Duk hotunan AFM suna cikin yanki na 15 μm × 15 μm, suna amfani da sandar sikelin launi iri ɗaya kamar yadda aka yiwa alama. (I) Tsarin kwaikwayo na electrodes na graphene monolayer mai tsari akan substrate na SEBS. (J) Taswirar kwane-kwane na babban nau'in logarithmic a cikin graphene monolayer da substrate na SEBS a nau'in waje na 20%. (K) Kwatanta yawan yankin tsagewa (gilashin ja), yawan yankin gungura (gilashin rawaya), da kuma kauri na saman (gilashin shuɗi) don tsarin graphene daban-daban.
Idan aka miƙe fina-finan MGG, akwai wata muhimmiyar hanya da za ta sa gungura su haɗu da yankunan graphene da suka fashe, suna kiyaye hanyar sadarwa mai ratsawa. Gunguraren graphene suna da kyau domin suna iya zama tsawon micrometers goma kuma don haka suna iya ɗaure tsagewar da yawanci take kaiwa ga sikelin micrometer. Bugu da ƙari, saboda gungura sun ƙunshi layuka da yawa na graphene, ana sa ran za su sami ƙarancin juriya. Idan aka kwatanta, ana buƙatar hanyoyin sadarwa na CNT masu yawa (ƙananan watsawa) don samar da damar haɗin kai mai kama da juna, saboda CNTs sun ƙanƙanta (yawanci 'yan micrometers a tsawon) kuma ba su da ikon watsawa fiye da gungura. A gefe guda kuma, kamar yadda aka nuna a cikin fig. S12, yayin da graphene ke tsagewa yayin shimfiɗawa don ɗaukar nauyin, gungura ba sa tsagewa, yana nuna cewa na ƙarshen na iya zamewa akan graphene da ke ƙasa. Dalilin da yasa ba sa fashewa wataƙila saboda tsarin da aka naɗe, wanda ya ƙunshi yadudduka da yawa na graphene (tsawon ~ 1 zuwa 2 0 μm, faɗin ~ 0.1 zuwa 1 μm, da tsayi ~ 10 zuwa 100 nm), wanda ke da mafi girman modulus mai tasiri fiye da graphene mai layi ɗaya. Kamar yadda Green da Hersam (42) suka ruwaito, hanyoyin sadarwa na CNT na ƙarfe (diamita na bututu na 1.0 nm) na iya cimma ƙarancin juriya na takarda < 100 ohms/sq duk da babban juriyar haɗuwa tsakanin CNTs. Idan aka yi la'akari da cewa gunguran graphene ɗinmu suna da faɗi na 0.1 zuwa 1 μm kuma gunguran G/G suna da wuraren hulɗa mafi girma fiye da CNTs, juriyar hulɗa da yankin hulɗa tsakanin gunguran graphene da graphene bai kamata su zama abubuwan da ke iyakancewa don kiyaye babban ƙarfin lantarki ba.
Graphene yana da modulus mafi girma fiye da substrate SEBS. Duk da cewa kauri mai inganci na electrode graphene ya yi ƙasa da na substrate, taurin graphene sau da yawa yana kama da na substrate (43, 44), wanda ke haifar da matsakaicin tasirin tsibiri mai tauri. Mun kwaikwayi nakasar graphene mai kauri 1-nm akan substrate SEBS (duba Ƙarin Kayan don cikakkun bayanai). Dangane da sakamakon kwaikwayon, lokacin da aka yi amfani da kashi 20% na nau'in SEBS a waje, matsakaicin nau'in a cikin graphene shine ~6.6% (Hoto na 4J da Hoto na S13D), wanda ya yi daidai da abubuwan da aka lura na gwaji (duba Hoto na S13). Mun kwatanta nau'in a cikin yankunan graphene da substrate da aka tsara ta amfani da na'urar hangen nesa kuma mun gano nau'in a cikin yankin substrate ya ninka nau'in a cikin yankin graphene. Wannan yana nuna cewa nau'in da aka yi amfani da shi akan samfuran electrode graphene na iya zama mai iyaka sosai, yana samar da tsibiran graphene masu tauri a saman SEBS (26, 43, 44).
Saboda haka, ikon electrodes na MGG na kiyaye babban ƙarfin lantarki a ƙarƙashin matsin lamba mai yawa yana yiwuwa ta hanyar manyan hanyoyi guda biyu: (i) Gungunan na iya haɗa yankuna da aka haɗa don kiyaye hanyar juyawar wutar lantarki, kuma (ii) zanen graphene/elastomer mai layi da yawa na iya zamewa a kan juna, wanda ke haifar da raguwar matsin lamba akan electrodes na graphene. Ga layuka da yawa na graphene da aka canjawa wuri akan elastomer, layukan ba su da alaƙa sosai da juna, wanda zai iya zamewa a martanin matsin lamba (27). Gungunan kuma sun ƙara tauri na layukan graphene, wanda zai iya taimakawa wajen ƙara rabuwa tsakanin layukan graphene don haka yana ba da damar zamewar layukan graphene.
Ana bin diddigin na'urorin carbon masu ƙarfi saboda ƙarancin farashi da kuma yawan aiki. A yanayinmu, an ƙera transistors masu ƙarfi na carbon ta amfani da ƙofar graphene ta ƙasa, hanyar haɗi/magudanar ruwa ta saman graphene, hanyar semiconductor mai tsari, da SEBS a matsayin dielectric (Hoto na 5A). Kamar yadda aka nuna a Hoto na 5B, na'urar carbon mai ƙarfi tare da CNTs a matsayin tushen/magudanar ruwa da ƙofar (na'urar ƙasa) ta fi haske fiye da na'urar da ke da electrodes na graphene (na'urar sama). Wannan saboda hanyoyin sadarwa na CNT suna buƙatar kauri mafi girma kuma, sakamakon haka, ƙananan watsawa na gani don cimma juriyar takarda kama da na graphene (hoto na S4). Hoto na 5 (C da D) yana nuna wakilcin canja wuri da fitarwa lanƙwasa kafin matsin lamba ga transistor da aka yi da electrodes na MGG masu layi biyu. Faɗin tashar da tsawon transistor mara ƙarfi sun kasance 800 da 100 μm, bi da bi. Rabon kunnawa/kashewa da aka auna ya fi 103 tare da kwararar kunnawa da kashewa a matakan 10−5 da 10−8 A, bi da bi. Lanƙwasa fitarwa tana nuna tsarin layi da kuma cikawa mai kyau tare da dogaro da ƙarfin ƙofa mai haske, wanda ke nuna alaƙar da ta dace tsakanin CNTs da electrodes na graphene (45). An lura da juriyar hulɗa da electrodes na graphene ƙasa da na fim ɗin Au da aka ƙafe (duba hoto na S14). Motsin jikewa na transistor mai shimfiɗawa yana da kusan 5.6 cm2/Vs, kama da na transistors na CNT iri ɗaya da aka tsara a polymer akan substrates masu ƙarfi na Si tare da 300-nm SiO2 a matsayin layin dielectric. Ana iya ƙara inganta motsi tare da ingantaccen yawan bututu da sauran nau'ikan bututu (46).
(A) Tsarin transistor mai shimfiɗawa bisa graphene. SWNTs, nanotubes na carbon mai bango ɗaya. (B) Hoton transistor masu shimfiɗawa da aka yi da electrodes na graphene (sama) da CNT (ƙasa). Bambancin bayyananniya a bayyane yake. (C da D) Canja wurin da fitarwa na transistor mai tushen graphene akan SEBS kafin matsi. (E da F) Canja wurin lanƙwasa, kunnawa da kashewa, rabon kunnawa/kashewa, da motsi na transistor mai tushen graphene a nau'ikan daban-daban.
Lokacin da aka miƙa na'urar mai haske, mai ɗauke da carbon a alkiblar da ke daidai da alkiblar jigilar caji, an lura da raguwar ƙarancin lalacewa har zuwa kashi 120%. A lokacin shimfiɗawa, motsi ya ci gaba da raguwa daga 5.6 cm2/Vs a kashi 0% na nauyin zuwa 2.5 cm2/Vs a kashi 120% na nauyin (Hoto na 5F). Mun kuma kwatanta aikin transistor don tsawon tashoshi daban-daban (duba tebur S1). Abin lura, a cikin nauyin da ya kai 105%, duk waɗannan transistor har yanzu suna nuna babban rabo na kunnawa/kashewa ( >103) da motsi ( >3 cm2/Vs). Bugu da ƙari, mun taƙaita duk aikin da aka yi kwanan nan kan transistor na carbon (duba tebur S2) (47–52). Ta hanyar inganta ƙera na'urori akan elastomers da amfani da MGGs a matsayin hulɗa, transistor ɗinmu na carbon suna nuna kyakkyawan aiki dangane da motsi da hysteresis da kuma kasancewa masu shimfiɗa sosai.
A matsayin aikace-aikacen transistor mai cikakken haske da shimfiɗawa, mun yi amfani da shi don sarrafa sauyawar LED (Hoto na 6A). Kamar yadda aka nuna a Hoto na 6B, ana iya ganin LED mai kore a sarari ta hanyar na'urar da za a iya shimfiɗawa ta hanyar amfani da duk-carbon da aka sanya kai tsaye a sama. Yayin da yake miƙewa zuwa ~100% (Hoto na 6, C da D), ƙarfin hasken LED bai canza ba, wanda ya yi daidai da aikin transistor da aka bayyana a sama (duba fim ɗin S1). Wannan shine rahoto na farko na na'urorin sarrafawa masu shimfiɗawa waɗanda aka yi ta amfani da electrodes na graphene, wanda ke nuna sabuwar yuwuwar amfani da na'urorin lantarki masu shimfiɗawa na graphene.
(A) Da'irar transistor don tuƙa LED. GND, ƙasa. (B) Hoton transistor mai shimfiɗawa da haske mai haske mai haske mai haske a 0% nau'in da aka ɗora a saman LED mai kore. (C) Transistor mai haske da haske mai haske wanda aka yi amfani da shi don canza LED ana ɗora shi a saman LED a 0% (hagu) da ~100% nau'in (dama). Farin kibiyoyi suna nuna alamun rawaya akan na'urar don nuna canjin nisa da ake miƙawa. (D) Kallon gefe na transistor mai shimfiɗawa, tare da tura LED cikin elastomer.
A ƙarshe, mun ƙirƙiri tsarin graphene mai haske wanda ke kula da babban ƙarfin lantarki a ƙarƙashin manyan nau'ikan lantarki kamar na'urorin lantarki masu shimfiɗawa, waɗanda graphene nanoscrolls ke kunnawa tsakanin layukan graphene da aka tara. Waɗannan tsarin lantarki na MGG mai layi biyu da uku akan elastomer na iya riƙe kashi 21 da 65%, bi da bi, na ƙarfin lantarki na 0% a cikin nau'in da ya kai 100%, idan aka kwatanta da cikakken asarar ƙarfin lantarki a nau'in 5% don na'urorin lantarki na graphene mai layi ɗaya. Ƙarin hanyoyin da ke gudana na gungura graphene da kuma raunin hulɗa tsakanin layukan da aka canja suna ba da gudummawa ga ingantaccen kwanciyar hankali a ƙarƙashin nau'in. Mun ƙara amfani da wannan tsarin graphene don ƙera transistors masu shimfiɗawa na carbon. Zuwa yanzu, wannan shine transistor mafi shimfiɗawa bisa graphene tare da mafi kyawun bayyanawa ba tare da amfani da buckling ba. Kodayake an gudanar da wannan binciken don ba da damar graphene don na'urorin lantarki masu shimfiɗawa, mun yi imanin cewa za a iya faɗaɗa wannan hanyar zuwa wasu kayan 2D don ba da damar na'urorin lantarki na 2D masu shimfiɗawa.
An shuka babban graphene CVD mai girman fili a kan foils ɗin Cu da aka dakatar (99.999%; Alfa Aesar) a ƙarƙashin matsin lamba na 0.5 mtorr tare da 50–SCCM (cibiyar cubic centimeter a minti ɗaya) CH4 da 20–SCCM H2 a matsayin abubuwan da suka fara aiki a 1000°C. An rufe ɓangarorin biyu na foil ɗin Cu da graphene mai layi ɗaya. An shafa wani siririn Layer na PMMA (2000 rpm; A4, Microchem) a gefe ɗaya na foil ɗin Cu, wanda ya samar da tsarin foil/G na PMMA/G/Cu. Daga baya, an jiƙa dukkan fim ɗin a cikin maganin ammonium persulfate [(NH4)2S2O8] na kimanin awanni 2 don cire foil ɗin Cu. A lokacin wannan aikin, graphene na baya wanda ba shi da kariya ya fara yage iyakokin hatsi sannan ya naɗe su zuwa gungura saboda matsin lamba a saman. An haɗa gungura a kan fim ɗin graphene na sama wanda PMMA ke tallafawa, wanda ya samar da gungura PMMA/G/G. Daga baya an wanke fina-finan da ruwan da aka cire daga ion sau da yawa sannan a sanya su a kan wani abu da aka yi niyya, kamar SiO2/Si mai tauri ko wani abu na filastik. Da zarar fim ɗin da aka haɗa ya bushe a kan substrate, an jiƙa samfurin a cikin acetone, acetone/IPA 1:1 (isopropyl alcohol), da IPA na tsawon daƙiƙa 30 kowannensu don cire PMMA. An dumama fina-finan a 100°C na tsawon mintuna 15 ko kuma a ajiye su a cikin injin tsotsa na dare ɗaya don cire ruwan da aka makale gaba ɗaya kafin a mayar da wani Layer na G/G scroll a kai. Wannan matakin shine a guji cire fim ɗin graphene daga substrate da kuma tabbatar da cikakken rufe MGGs yayin sakin layin PMMA.
An lura da yanayin tsarin MGG ta amfani da na'urar hangen nesa ta gani (Leica) da na'urar hangen nesa ta lantarki (1 kV; FEI). An yi amfani da na'urar hangen nesa ta ƙarfin atomic (Nanoscope III, Digital Instrument) a yanayin taɓawa don lura da cikakkun bayanai na gunguran G. An gwada bayyananniya ta fim ta amfani da na'urar hangen nesa ta ultraviolet (Agilent Cary 6000i). Don gwaje-gwajen lokacin da nau'in ya kasance a kan alkiblar da ke tsaye na kwararar yanzu, an yi amfani da photolithography da plasma O2 don tsara tsarin graphene zuwa tsiri (~300 μm faɗi da ~2000 μm tsayi), kuma an sanya na'urorin lantarki na Au (50 nm) ta hanyar amfani da abin rufe fuska a ƙarshen gefen biyu na dogon gefe. An sanya tsiri na graphene a cikin hulɗa da wani elastomer na SEBS (faɗin ~ 2 cm da tsawon ~ 5 cm), tare da dogon axis na tsiri a layi ɗaya da ɗan gajeren gefen SEBS sannan sai aka biyo baya da BOE (buffered oxide etch) (HF:H2O 1:6) etching da eutectic gallium indium (EGaIn) a matsayin haɗin lantarki. Don gwaje-gwajen nau'in layi ɗaya, an canja tsarin graphene mara tsari (~ 5 × 10 mm) zuwa kan ƙananan SEBS, tare da dogayen gatari a layi ɗaya da dogon gefen SEBS. Ga duka shari'o'in, an shimfiɗa dukkan G (ba tare da G scrolls)/SEBS tare da dogon gefen elastomer a cikin na'urar hannu, kuma a wurin, mun auna canje-canjen juriyarsu a ƙarƙashin matsin lamba a tashar bincike tare da na'urar nazarin semiconductor (Keithley 4200-SCS).
An ƙera transistors masu shimfiɗawa da haske waɗanda ke kan wani abu mai roba ta hanyar waɗannan hanyoyin don guje wa lalacewar sinadarai na polymer dielectric da substrate. An canja tsarin MGG zuwa SEBS a matsayin electrodes na ƙofa. Don samun wani Layer na polymer dielectric mai sirara (kauri 2 μm), an shafa maganin SEBS toluene (80 mg/ml) a kan wani sinadari mai suna octadecyltrichlorosilane (OTS) – wanda aka gyara a 1000 rpm na tsawon minti 1. Ana iya canja wurin siraran fim ɗin dielectric cikin sauƙi daga saman OTS mai kama da hydrophobic zuwa kan sinadari na SEBS da aka rufe da graphene da aka shirya. Ana iya yin capacitor ta hanyar ajiye wani electrode na sama mai ruwa-ƙarfe (EGaIn; Sigma-Aldrich) don tantance capacitance azaman aikin matsi ta amfani da mitar LCR (inductance, capacitance, resistance) (Agilent). Sauran ɓangaren na transistor ya ƙunshi CNTs masu sarrafa semiconductor na polymer, bin hanyoyin da aka ruwaito a baya (53). An ƙera na'urorin lantarki masu tushen/magudanar ruwa a kan siraran SiO2/Si masu tauri. Daga baya, an haɗa sassan biyu, dielectric/G/SEBS da CNTs/tsarin G/SiO2/Si, a tsakaninsu, sannan aka jiƙa su a cikin BOE don cire siraran SiO2/Si masu tauri. Don haka, an ƙera transistors masu cikakken haske da kuma masu shimfiɗawa. An yi gwajin lantarki a ƙarƙashin matsin lamba ta hanyar saita shimfiɗa hannu kamar yadda aka ambata a baya.
Ana samun ƙarin kayan aikin wannan labarin a http://advances.sciencemag.org/cgi/content/full/3/9/e1700159/DC1
Hoto na S1. Hotunan na'urar hangen nesa ta MGG mai layi ɗaya akan ƙananan SiO2/Si a girman girma daban-daban.
Hoto na S4. Kwatanta juriyar takardar bincike biyu da kuma watsawa @550 nm na graphene mai layi ɗaya, mai layi biyu da mai layi uku (murabba'ai baƙi), MGG (da'irori ja), da CNTs (alwatika mai shuɗi).
siffa ta S7. Canjin juriya na daidaito na MGGs masu layi ɗaya da biyu (baƙi) da G (ja) a ƙarƙashin nau'in zagaye na ~1000 da ke ɗaukar nauyin nau'in layi ɗaya na 40 da 90%, bi da bi.
Hoto na S10. Hoton SEM na MGG mai layi uku akan elastomer na SEBS bayan an yi amfani da shi, yana nuna dogon gungura a kan tsage-tsage da dama.
Hoto na S12. Hoton AFM na MGG mai layi uku akan siririn elastomer na SEBS mai kashi 20%, yana nuna cewa gungura ta haɗu akan tsagewa.
Tebur S1. Motsin transistors na carbon nanotube mai bango ɗaya-biyar MGG a tsawon tashoshi daban-daban kafin da kuma bayan wahala.
Wannan wani labari ne da ake iya amfani da shi a bude wanda aka rarraba a karkashin sharuɗɗan lasisin Creative Commons Attribution-NonCommercial, wanda ke ba da izinin amfani, rarrabawa, da kuma sake bugawa a kowace hanya, matuƙar amfanin da aka samu ba don amfanin kasuwanci ba ne kuma muddin an ambaci ainihin aikin da ya dace.
LURA: Muna neman adireshin imel ɗinka ne kawai domin mutumin da kake ba da shawara a shafin ya san cewa kana son ya gan shi, kuma ba wasikun banza ba ne. Ba ma ɗaukar kowane adireshin imel.
Wannan tambayar don gwada ko kai baƙo ne na ɗan adam ko a'a, da kuma hana aika saƙonnin banza ta atomatik.
Daga Nan Liu, Alex Chortos, Ting Lei, Lihua Jin, Taeho Roy Kim, Won-Gyu Bae, Chenxin Zhu, Sihong Wang, Raphael Pfattner, Xiyuan Chen, Robert Sinclair, Zhenan Bao
Daga Nan Liu, Alex Chortos, Ting Lei, Lihua Jin, Taeho Roy Kim, Won-Gyu Bae, Chenxin Zhu, Sihong Wang, Raphael Pfattner, Xiyuan Chen, Robert Sinclair, Zhenan Bao
© 2021 Ƙungiyar Amirka don Ci gaban Kimiyya. An kiyaye duk haƙƙoƙin. AAAS abokin tarayya ne na HINARI, AGORA, OARE, CHORUS, CLOCKSS, CrossRef da COUNTER. Ci gaban Kimiyya ISSN 2375-2548.