Ii-electrode ze-graphene ezicacileyo nezinokolulwa

Izinto ezinemilinganiselo emibini, ezifana ne-graphene, zinomtsalane kuzo zombini izicelo ze-semiconductor eziqhelekileyo kunye nezicelo ezisandula ukwenziwa kwi-electronics eziguquguqukayo. Nangona kunjalo, amandla aphezulu okutsalwa kwe-graphene aphumela ekuqhekekeni kwi-strain ephantsi, okwenza kube nzima ukusebenzisa iipropati zayo ezingaqhelekanga ze-elektroniki kwi-electronics ezinwebekayo. Ukuze sikwazi ukusebenza ngokugqwesileyo kwee-conducters ze-graphene ezicacileyo ezixhomekeke kwi-strain, senze ii-nanoscrolls ze-graphene phakathi kwee-stacked graphene layers, ezibizwa ngokuba yi-multilayer graphene/graphene scrolls (MGGs). Phantsi kwe-strain, ezinye ii-scrolls zahlanganisa iindawo eziqhekekileyo ze-graphene ukuze zigcine inethiwekhi ye-percolating evumela i-conductivity entle kwi-strain ephezulu. Ii-Trilayer MGGs ezixhaswe kwi-elastomers zigcine i-65% ye-conductance yazo yokuqala kwi-100% ye-strain, ethe nkqo kwicala lokuhamba komsinga, ngelixa iifilimu ze-trilayer ze-graphene ezingenayo i-nanoscrolls zigcine i-25% kuphela ye-conductance yazo yokuqala. I-transistor ye-all-carbon enokolulwa eyenziwe kusetyenziswa ii-MGG njengoko ii-electrodes zibonise ukuhanjiswa kwe->90% kwaye zagcina i-60% yemveliso yayo yangoku yokuqala kwi-120% yoxinzelelo (ngokufana necala lothutho lwetshaja). Ezi transistor ze-all-carbon ezinokolulwa kakhulu nezicacileyo zinokwenza i-optoelectronics enobuchule enokolulwa.
I-stretchable transparent electronics yintsimi ekhulayo enezicelo ezibalulekileyo kwiinkqubo eziphucukileyo ze-biointegrated (1, 2) kunye nokukwazi ukudibana ne-optoelectronics ezoluliweyo (3, 4) ukuvelisa iirobhothi ezithambileyo kunye neziboniso ezintsonkothileyo. I-Graphene ibonisa iipropati ezinqwenelekayo kakhulu zobukhulu be-athomu, ukubonakala okuphezulu, kunye nokuqhuba okuphezulu, kodwa ukusetyenziswa kwayo kwizicelo ezoluliweyo kuye kwathintelwa kukuthambekela kwayo kokuqhekeka kwiintlobo ezincinci. Ukoyisa imida ye-graphene kunokuvumela ukusebenza okutsha kwizixhobo ezoluliweyo transparent.
Iipropati ezikhethekileyo ze-graphene ziyenza ibe ngumviwa oqinileyo kwisizukulwana esilandelayo see-electrode eziqhubayo ezibonakalayo (5, 6). Xa kuthelekiswa ne-conducter eguquguqukayo esetyenziswa kakhulu, i-indium tin oxide [ITO; 100 ohms/square (sq) kwi-90% transparency ], i-monolayer graphene ekhuliswe yi-chemical vapor deposition (CVD) inomxube ofanayo wokuxhathisa ishiti (125 ohms/sq) kunye nokucaca (97.4%) (5). Ukongeza, iifilimu ze-graphene zinokuguquguquka okungaqhelekanga xa kuthelekiswa ne-ITO (7). Umzekelo, kwi-substrate yeplastiki, ukujikeleza kwayo kunokugcinwa nokuba kujikeleze i-radius ye-curvature encinci njenge-0.8 mm (8). Ukuphucula ngakumbi ukusebenza kwayo kombane njenge-conducter eguquguqukayo ebonakalayo, imisebenzi yangaphambili iphuhlise izixhobo ze-graphene hybrid ezine-nanowires zesilivere ezinemilinganiselo enye (1D) okanye ii-carbon nanotubes (CNTs) (9–11). Ngaphezu koko, i-graphene isetyenzisiwe njengee-electrodes kwii-semiconductors ze-heterostructural ezixutyiweyo (ezifana ne-2D bulk Si, ii-nanowires/nanotubes ze-1D, kunye nee-0D quantum dots) (12), ii-transistors eziguquguqukayo, iiseli zelanga, kunye nee-light-emitting diodes (ii-LED) (13–23).
Nangona i-graphene ibonakalise iziphumo ezithembisayo kwi-electronics eziguquguqukayo, ukusetyenziswa kwayo kwi-electronics ezisolulwayo kuye kwancitshiswa ziimpawu zayo zoomatshini (17, 24, 25); i-graphene inokuqina okungaphakathi kwe-340 N/m kunye ne-Young's modulus ye-0.5 TPa (26). Inethiwekhi enamandla ye-carbon-carbon ayiboneleli ngeendlela zokusasaza amandla kwi-strain esetyenzisiweyo kwaye ngenxa yoko iyaqhekeka ngokulula kwi-strain engaphantsi kwe-5%. Umzekelo, i-CVD graphene edluliselwe kwi-polydimethylsiloxane (PDMS) elastic substrate inokugcina kuphela i-conductivity yayo kwi-strain engaphantsi kwe-6% (8). Ubalo lwethiyori lubonisa ukuba ukuqhekeka kunye nokudibana phakathi kwe-layers ezahlukeneyo kufuneka kunciphise kakhulu ukuqina (26). Ngokufaka i-graphene kwii-layers ezininzi, kuxelwa ukuba le graphene ye-bi- okanye ye-trilayer inokolulwa ukuya kwi-strain ye-30%, ibonisa utshintsho lokumelana oluphindwe ka-13 kune-monolayer graphene (27). Nangona kunjalo, olu hlobo lokunwebeka lusengaphantsi kakhulu kunee-onductors ze-c ezinwebekayo zanamhlanje (28, 29).
Iitransista zibalulekile kwizicelo ezinokolulwa kuba zivumela ukufundwa kwesensor okuntsonkothileyo kunye nohlalutyo lwesignali (30, 31). Iitransista kwiPDMS ezine-graphene enezingqimba ezininzi njengee-electrode zomthombo/zokukhupha kunye nezinto zetshaneli zinokugcina umsebenzi wombane ukuya kuthi ga kwi-5% yoxinzelelo (32), olungaphantsi kakhulu kwexabiso elifunekayo (~50%) kwiisensors ezinxibekayo zokujonga impilo kunye nolusu lwe-elektroniki (33, 34). Kutshanje, indlela ye-graphene kirigami iye yahlolwa, kwaye i-transistor evalwe yi-electrolyte engamanzi inokolulwa ukuya kuthi ga kwi-240% (35). Nangona kunjalo, le ndlela ifuna i-graphene exhonyiweyo, nto leyo eyenza kube nzima inkqubo yokwenza.
Apha, sifumana izixhobo ze-graphene ezinwebeka kakhulu ngokuhlanganisa ii-graphene scrolls (~1 ukuya kwi-20 μm ubude, ~0.1 ukuya kwi-1 μm ububanzi, kunye ~10 ukuya kwi-100 nm ukuphakama) phakathi kwee-graphene layers. Sicinga ukuba ezi graphene scrolls zinokubonelela ngeendlela zokuqhuba ukuvala iintanda kwiishiti ze-graphene, ngaloo ndlela zigcina i-conductivity ephezulu phantsi koxinzelelo. Ii-graphene scrolls azidingi synthesis okanye inkqubo eyongezelelweyo; zenziwe ngokwendalo ngexesha lenkqubo yokudlulisa amanzi. Ngokusebenzisa ii-multilayer G/G (graphene/graphene) scrolls (MGGs) graphene stretchable electrodes (source/drain and gate) kunye ne-semiconducting CNTs, sikwazile ukubonisa ii-transistors ze-all-carbon transistors ezicacileyo kakhulu nezinwebeka kakhulu, ezinokwandiswa ukuya kwi-120% strain (ngokufana necala lothutho lwetshaja) kwaye zigcine i-60% yemveliso yazo yokuqala yangoku. Le yeyona transistor isekelwe kwi-carbon transistor ecacileyo kakhulu ukuza kuthi ga ngoku, kwaye inika i-current eyaneleyo yokuqhuba i-inorganic LED.
Ukuze sikwazi ukwenza ii-electrode ze-graphene ezivulekileyo nezinokwelulwa kwindawo enkulu, sikhethe i-graphene ekhuliswe nge-CVD kwi-Cu foil. I-Cu foil yaxhonywa embindini wetyhubhu ye-CVD quartz ukuvumela ukukhula kwe-graphene kumacala omabini, senza izakhiwo ze-G/Cu/G. Ukuze sidlulisele i-graphene, saqala ngokuyisonta umaleko omncinci we-poly(methyl methacrylate) (PMMA) ukukhusela icala elinye le-graphene, esalibiza ngokuba yi-topside graphene (ngokuchaseneyo nelinye icala le-graphene), kwaye emva koko, yonke ifilimu (PMMA/top graphene/Cu/bottom graphene) yacwiliswa kwisisombululo se-(NH4)2S2O8 ukuze ikhuphe i-Cu foil. I-graphene esecaleni elingaphantsi ngaphandle kwe-PMMA coating ayinakuphepheka ukuba ibe neentanda kunye neziphene ezivumela i-etchant ukuba ingene (36, 37). Njengoko kubonisiwe kuMfanekiso 1A, phantsi kwempembelelo yoxinzelelo lomphezulu, iindawo ze-graphene ezikhutshiweyo zasongwa zaba yi-scrolls kwaye emva koko zancamathiselwa kwifilimu eseleyo ye-top-G/PMMA. Iiscrolls ze-G/G eziphezulu zinokudluliselwa nakweyiphi na i-substrate, njenge-SiO2/Si, iglasi, okanye i-polymer ethambileyo. Ukuphinda le nkqubo yokudlulisela amaxesha amaninzi kwi-substrate efanayo kunika izakhiwo ze-MGG.
(A) Umfanekiso ocacileyo wenkqubo yokwenziwa kweeMGG njenge-electrode enokolulwa. Ngexesha lokudluliselwa kwegraphene, i-graphene engasemva kwi-Cu foil yaphulwa kwimida nakwiimpazamo, yasongwa yaba ziimo ezingacwangciswanga, yaza yaqhotyoshelwa ngokuqinileyo kwiifilimu eziphezulu, yenza ii-nanoscrolls. Ikhathuni yesine ibonisa isakhiwo se-MGG esihlanganisiweyo. (B kunye no-C) Iimpawu ze-TEM eziphezulu ze-MGG ye-monolayer, ezigxile kwi-monolayer graphene (B) kunye nommandla we-scroll (C), ngokwahlukeneyo. I-inset ye-(B) ngumfanekiso ophantsi wokukhulisa obonisa imo iyonke yee-MGG ze-monolayer kwigridi ye-TEM. Ii-insets ze-(C) ziiprofayili zobunzulu ezithathwe kwiibhokisi ezingxande eziboniswe kumfanekiso, apho umgama phakathi kweenqwelo-moya ze-athomu yi-0.34 kunye ne-0.41 nm. (D) I-Carbon K-edge EEL spectrum ene-graphitic π* kunye neencopho ze-σ* ezibhalwe. (E) Umfanekiso we-Sectional AFM we-monolayer G/G scrolls eneprofayili yokuphakama kumgca otyheli onamachaphaza. (F ukuya ku-I) I-Optical microscopy kunye nemifanekiso ye-AFM ye-trilayer G engenazo (F kunye no-H) kunye ne-scrolls (G kunye no-I) kwi-300-nm-thick SiO2/Si substrates, ngokulandelelana. I-scrolls ezimeleyo kunye nemibimbi ziphawulwe ukuze zibonise umahluko wazo.
Ukuqinisekisa ukuba imisongo yi-graphene egoqwe ngokwendalo, senze izifundo ze-spectroscopy ye-transmission electron microscopy (TEM) kunye ne-electron energy loss (EEL) kwizakhiwo ze-monolayer top-G/G scroll. Umfanekiso 1B ubonisa isakhiwo se-hexagonal se-monolayer graphene, kwaye i-inset yimopology iyonke yefilimu egqunywe kumngxuma omnye wekhabhoni we-TEM grid. I-monolayer graphene ijikeleza uninzi lwegridi, kwaye ezinye ii-graphene flakes xa kukho ii-stacks ezininzi zee-hexagonal rings ziyavela (Umzobo 1B). Ngokusondeza kwi-scroll nganye (Umzobo 1C), sibone inani elikhulu lee-graphene lattice fringes, kunye ne-lattice space kuluhlu lwe-0.34 ukuya kwi-0.41 nm. Ezi zilinganiso zibonisa ukuba ii-flakes zigoqwe ngokungacwangciswanga kwaye aziyo-graphite egqibeleleyo, ene-lattice space ye-0.34 nm kwi-"ABAB" layer stacking. Umfanekiso 1D ubonisa i-carbon K-edge EEL spectrum, apho incopho kwi-285 eV ivela kwi-π* orbital kwaye enye ejikeleze i-290 eV ibangelwa kukutshintsha kwe-σ* orbital. Kuyabonakala ukuba ukubophelela kwe-sp2 kuyalawula kolu lwakhiwo, okuqinisekisa ukuba imiqulu inemifanekiso emininzi.
Imifanekiso ye-optical microscopy kunye ne-atomic force microscopy (AFM) inika ulwazi malunga nokusasazwa kwe-graphene nanoscrolls kwi-MGGs (Umzobo 1, E ukuya ku-G, kunye neefigs. S1 kunye ne-S2). Ii-scrolls zisasazwa ngokungacwangciswanga phezu komphezulu, kwaye uxinano lwazo ngaphakathi luyanda ngokulinganayo kwinani leeleya ezihlanganisiweyo. Ii-scrolls ezininzi zidityaniswe zibe ngamaqhina kwaye zibonisa ukuphakama okungafaniyo kuluhlu lwe-10 ukuya kwi-100 nm. Ziyi-1 ukuya kwi-20 μm ubude kunye ne-0.1 ukuya kwi-1 μm ububanzi, kuxhomekeke kubukhulu bee-graphene flakes zazo zokuqala. Njengoko kubonisiwe kumzobo 1 (H kunye no-I), ii-scrolls zinobukhulu obukhulu kakhulu kunee-wrinkles, nto leyo ekhokelela kunxibelelwano oluqinileyo phakathi kweeleya ze-graphene.
Ukulinganisa iipropati zombane, senze iipatheni zeefilimu ze-graphene ezinezakhiwo ze-scroll okanye ezingenazo kunye ne-layer stacking zibe yi-300-μm ububanzi kunye ne-2000-μm ubude sisebenzisa i-photolithography. Ukumelana kwe-two-probe njengomsebenzi woxinzelelo kulinganiswe phantsi kweemeko ze-ambient. Ubukho be-scrolls bunciphise i-resistivity ye-monolayer graphene nge-80% kunye nokwehla kwe-2.2% kuphela kwi-transmittance (umzobo S4). Oku kuqinisekisa ukuba ii-nanoscrolls, ezinobuninzi bombane obuphezulu ukuya kuthi ga kwi-5 × 107 A/cm2 (38, 39), zenza igalelo elihle kakhulu lombane kwi-MGGs. Phakathi kwazo zonke ii-mono-, bi-, kunye ne-trilayer plain graphene kunye ne-MGGs, i-trilayer MGG ine-conductance engcono kakhulu ene-transparency ephantse ibe yi-90%. Ukuthelekisa neminye imithombo ye-graphene echazwe kwiincwadi, sikwalinganise ukumelana kwamaphepha amane (umzobo S5) saza sazidwelisa njengomsebenzi wokudluliselwa kwi-550 nm (umzobo S6) kwiFig. 2A. I-MGG ibonisa ukuhanjiswa kwamandla kunye nokucaca okufana okanye okuphezulu kune-graphene edibeneyo eyenziwe nge-artificially stacked multilayer yer plain kunye ne-graphene oxide encitshisiweyo (RGO) (6, 8, 18). Qaphela ukuba ukumelana kwamaphepha e-graphene edibeneyo eyenziwe nge-artificially stacked multilayer plain evela kwiincwadi kuphezulu kancinci kune-MGG yethu, mhlawumbi ngenxa yeemeko zabo zokukhula ezingaphuculwanga kunye nendlela yokudlulisa.
(A) Ukumelana kwamaphepha amane okukroba ngokuchasene nokudluliselwa kwi-550 nm kwiintlobo ezahlukeneyo zegraphene, apho izikwere ezimnyama zibonisa i-MGGs ye-mono-, bi-, kunye ne-trilayer; izangqa ezibomvu kunye noonxantathu abaluhlaza okwesibhakabhaka zihambelana ne-graphene ecacileyo enezingqimba ezininzi ekhuliswe kwi-Cu kunye ne-Ni kwizifundo zikaLi et al. (6) kunye noKim et al. (8), ngokulandelelana, kwaye emva koko idluliselwe kwi-SiO2/Si okanye kwi-quartz; kwaye oonxantathu abaluhlaza baxabisa i-RGO kwiidigri ezahlukeneyo zokunciphisa ukusuka kwisifundo sikaBonaccorso et al. (18). (B kunye no-C) Utshintsho oluqhelekileyo lokumelana kwe-MGGs ye-mono-, bi- kunye ne-trilayer kunye ne-G njengomsebenzi woxinzelelo oluthe nkqo (B) kunye noxinzelelo oluhambelanayo (C) ukuya kwicala lokuhamba kwangoku. (D) Utshintsho oluqhelekileyo lokumelana kwe-bilayer G (ebomvu) kunye ne-MGG (emnyama) phantsi koxinzelelo olujikelezayo olufikelela kwi-50% yoxinzelelo oluhambelanayo. (E) Utshintsho oluqhelekileyo lokumelana kwe-trilayer G (ebomvu) kunye ne-MGG (emnyama) phantsi koxinzelelo oluhambelanayo olufikelela kwi-90% yoxinzelelo oluhambelanayo. (F) Utshintsho oluqhelekileyo lwe-capacitance ye-mono-, bi- kunye ne-trilayer G kunye ne-bi- kunye ne-trilayer MGGs njengomsebenzi woxinzelelo. I-inset yisakhiwo se-capacitor, apho i-polymer substrate yi-SEBS kwaye umaleko we-polymer dielectric yi-2-μm-thick SEBS.
Ukuvavanya ukusebenza kwe-MGG okuxhomekeke kuxinzelelo, sidlulisele i-graphene kwi-thermoplastic elastomer styrene-ethylene-butadiene-styrene (SEBS) substrates (~2 cm ububanzi kunye ~5 cm ubude), kwaye ukuhanjiswa kwamandla kwalinganiswa njengoko i-substrate yoluliwe (jonga izixhobo kunye neendlela) zombini zithe nkqo kwaye zihambelana necala lokuhamba kombane (Umzobo 2, B kunye no-C). Ukuziphatha kombane okuxhomekeke kuxinzelelo kuphucukile ngokufakwa kwe-nanoscrolls kunye nokwanda kwamanani eeleya ze-graphene. Umzekelo, xa uxinzelelo luthe nkqo kuhambo lombane, kwi-monolayer graphene, ukongezwa kwe-scrolls kwandisa uxinzelelo xa umbane uqhekeka ukusuka kwi-5 ukuya kwi-70%. Ukunyamezela koxinzelelo lwe-trilayer graphene nako kuphuculwe kakhulu xa kuthelekiswa ne-monolayer graphene. Nge-nanoscrolls, kwi-100% perpendicular strain, ukumelana kwesakhiwo se-trilayer MGG kunyuke nge-50% kuphela, xa kuthelekiswa ne-300% kwi-trilayer graphene ngaphandle kwe-scrolls. Utshintsho lokumelana phantsi komthwalo woxinzelelo lwe-cyclic luphandwe. Ukuthelekisa (Umzobo 2D), ukumelana kwefilimu ye-bilayer graphene ecacileyo kwanda malunga nezihlandlo ezi-7.5 emva kwemijikelo engama-700 kuxinzelelo oluthe nkqo lwama-50% kwaye kwaqhubeka nokwanda ngokuxinana kumjikelo ngamnye. Kwelinye icala, ukumelana kwe-MGG ye-bilayer kwanda kuphela malunga nezihlandlo ezi-2.5 emva kwemijikelo engama-700. Ukusebenzisa uxinzelelo olufikelela kwi-90% kwicala elihambelanayo, ukumelana kwe-trilayer graphene kwanda ~izihlandlo ezili-100 emva kwemijikelo eli-1000, ngelixa kungaphezulu kwezihlandlo ezi-8 kwi-trilayer MGG (Umzobo 2E). Iziphumo zokujikeleza ziboniswe kumzobo S7. Ukwanda ngokukhawuleza kokuxhathisa kwicala elihambelanayo kungenxa yokuba ukujongwa kweentanda kuthe nkqo kwicala lokuhamba komsinga. Ukuphambuka kokuxhathisa ngexesha lokulayisha nokukhupha uxinzelelo kungenxa yokubuyiselwa kwe-viscoelastic ye-SEBS elastomer substrate. Ukumelana okuzinzileyo kwee-MGG strips ngexesha lokuhamba ngebhayisikile kungenxa yokubakho kwee-scrolls ezinkulu ezinokuvala iindawo eziqhekekileyo ze-graphene (njengoko kubonwe yi-AFM), zinceda ukugcina indlela ejikeleza. Le meko yokugcina ukuhanjiswa kwendlela ejikelezayo ibikwe ngaphambili kwiifilimu zesinyithi eziqhekekileyo okanye ze-semiconductor kwi-elastomer substrates (40, 41).
Ukuvavanya ezi filimu ezisekelwe kwi-graphene njengee-electrode zesango kwizixhobo ezinokolulwa, sigubungele umaleko we-graphene ngomaleko we-dielectric we-SEBS (ubude obuyi-2 μm) saza sajonga utshintsho lwe-capacitance ye-dielectric njengomsebenzi woxinzelelo (jonga uMzobo 2F kunye neeMpahla ezongezelelweyo ukuze ufumane iinkcukacha). Siqaphele ukuba ii-capacitance ezine-electrode ze-monolayer ecacileyo kunye ne-bilayer graphene zehla ngokukhawuleza ngenxa yokulahleka kokuqhuba kwe-graphene ngaphakathi. Ngokwahlukileyo koko, ii-capacitance ezivalwe yi-MGGs kunye ne-graphene ye-trilayer ecacileyo zibonise ukwanda kwe-capacitance kunye noxinzelelo, okulindelekileyo ngenxa yokuncipha kobukhulu be-dielectric kunye noxinzelelo. Ukwanda okulindelweyo kwi-capacitance kuhambelane kakuhle nesakhiwo se-MGG (umzobo S8). Oku kubonisa ukuba i-MGG ifanelekile njenge-electrode yesango kwii-transistors ezinokolulwa.
Ukuze siqhubeke siphanda indima ye-1D graphene scroll kwi-strain tolerance of electrical conductivity kunye nokulawula ngcono ukwahlukana phakathi kwe-graphene layers, sisebenzise ii-CNTs ezifakwe i-spray ukuze zithathe indawo ye-graphene scrolls (jonga kwi-Supplementary Materials). Ukuze silingise izakhiwo ze-MGG, sibeke uxinano oluthathu lwe-CNTs (oko kukuthi, i-CNT1).
(A ukuya ku-C) Imifanekiso ye-AFM yeentlobo ezintathu ezahlukeneyo ze-CNTs (CNT1)
Ukuze siqonde ngakumbi amandla azo njengee-electrode ze-elektroniki ezisolulwayo, sihlolisise ngokucwangcisiweyo iimofoloji ze-MGG kunye ne-G-CNT-G phantsi koxinzelelo. I-optical microscopy kunye ne-scanning electron microscopy (SEM) azizondlela zisebenzayo zokuchonga kuba zombini azinawo umahluko wombala kwaye i-SEM ixhomekeke kwimifanekiso yezinto ezisetyenzisiweyo ngexesha lokuskena i-electron xa i-graphene ikwi-polymer substrates (imizobo S9 kunye ne-S10). Ukuze sijonge umphezulu we-graphene phantsi koxinzelelo, siqokelele imilinganiselo ye-AFM kwi-trilayer MGGs kunye ne-plain graphene emva kokudluliselwa kwi-substrates ezincinci kakhulu (~0.1 mm ubukhulu) kunye ne-elastic SEBS. Ngenxa yeziphene zangaphakathi kwi-CVD graphene kunye nomonakalo wangaphandle ngexesha lenkqubo yokudlulisa, ii-cracks ziyaveliswa kwi-strained graphene, kwaye ngoxinzelelo olukhulayo, ii-cracks zaba nkulu (Umzobo 4, A ukuya ku-D). Ngokuxhomekeke kwisakhiwo se-stacking see-electrodes ezisekwe kwi-carbon, ii-cracks zibonisa iimofoloji ezahlukeneyo (umzobo S11) (27). Uxinano lwendawo yokuqhekeka (oluchazwa njengendawo yokuqhekeka/indawo ehlalutyiweyo) lwe-graphene enezintlu ezininzi lungaphantsi kolo lwe-graphene enezintlu ezimbini emva kokuxinana, nto leyo ehambelana nokwanda kokuqhuba kombane kwi-MGGs. Kwelinye icala, imiqulu idla ngokubonwa ukuze ivale imiqulu, inike iindlela ezongezelelweyo zokuqhuba kwifilimu exineneyo. Umzekelo, njengoko kubhalwe kumfanekiso weFig. 4B, umqulu obanzi uwele phezu komqulu kwi-MGG enezintlu ezintathu, kodwa akukho mqulu ubonwe kwi-graphene ecacileyo (Fig. 4, E ukuya kwi-H). Ngokufanayo, ii-CNTs nazo zivale imiqulu kwi-graphene (fig. S11). Uxinano lwendawo yokuqhekeka, uxinano lwendawo yokuskrola, kunye noburhabaxa beefilimu zishwankathelwe kwiFig. 4K.
(A ukuya ku-H) Imifanekiso ye-AFM ye-trilayer G/G scrolls (A ukuya ku-D) kunye nezakhiwo ze-trilayer G (E ukuya ku-H) kwi-elastomer encinci kakhulu ye-SEBS (~0.1 mm ubukhulu) kwi-strain engu-0, 20, 60, kunye ne-100%. Iimfanta ezimeleyo kunye nee-scrolls zikhonjiswe ngeentolo. Zonke imifanekiso ye-AFM zikwindawo ye-15 μm × 15 μm, kusetyenziswa ibha yesikali yombala efanayo njengoko iphawulwe. (I) I-geometry yokulinganisa yee-electrodes ze-graphene ze-monolayer ezinemifanekiso kwi-substrate ye-SEBS. (J) Imephu ye-contour yokulinganisa yoxinzelelo olukhulu lwe-logarithmic kwi-graphene ye-monolayer kunye ne-substrate ye-SEBS kwi-strain yangaphandle ye-20%. (K) Uthelekiso loxinano lwendawo yokuqhekeka (ikholamu ebomvu), uxinano lwendawo yokuskrola (ikholamu etyheli), kunye noburhabaxa bomphezulu (ikholamu eluhlaza okwesibhakabhaka) kwizakhiwo ezahlukeneyo ze-graphene.
Xa iifilimu zeMGG zoluliwe, kukho indlela ebalulekileyo eyongezelelweyo yokuba imiqulu ikwazi ukuvala iindawo eziqhekekileyo zegraphene, igcine inethiwekhi ejikelezayo. Imiqulu yegraphene iyathembisa kuba inokuba ngamashumi ee-micrometer ubude kwaye ngoko ke iyakwazi ukuvala imiqulu eqhele ukufikelela kwisikali se-micrometer. Ngaphezu koko, ngenxa yokuba imiqulu inee-multilayers zegraphene, kulindeleke ukuba ibe nokumelana okuphantsi. Xa kuthelekiswa, iinethiwekhi ze-CNT ezixineneyo (eziphantsi zokudlulisa) ziyafuneka ukubonelela ngamandla okuhambisa ahambelanayo, njengoko ii-CNT zincinci (ngesiqhelo zii-micrometer ezimbalwa ubude) kwaye azikwazi ukuqhuba abaqhubi kangako kunemiqulu. Kwelinye icala, njengoko kubonisiwe kumzobo S12, ngelixa i-graphene iqhekeka ngexesha lokusolula ukuze ivumelane noxinzelelo, imiqulu ayiqhekeki, nto leyo ebonisa ukuba le yokugqibela isenokuba ityibilika kwi-graphene engaphantsi. Isizathu sokuba zingaqhekeki kusenokwenzeka ukuba kungenxa yesakhiwo esigoqiweyo, esenziwe ziingqimba ezininzi ze-graphene (~1 ukuya kwi-2 0 μm ubude, ~0.1 ukuya kwi-1 μm ububanzi, kunye ~10 ukuya kwi-100 nm ukuphakama), ene-modulus esebenzayo ephezulu kune-graphene yomaleko omnye. Njengoko kubikwe nguGreen noHersam (42), iinethiwekhi ze-CNT zentsimbi (ububanzi betyhubhu ye-1.0 nm) zinokufikelela kukumelana okuphantsi kwephepha elingaphantsi kwe-100 ohms/sq nangona kukho ukumelana okukhulu phakathi kwe-CNTs. Xa ucinga ukuba ii-graphene scrolls zethu zinobubanzi be-0.1 ukuya kwi-1 μm kwaye ii-G/G scrolls zinendawo enkulu yokunxibelelana kune-CNTs, ukumelana kokunxibelelana kunye nendawo yokunxibelelana phakathi kwe-graphene kunye ne-graphene scrolls akufuneki zibe zizinto ezithintela ukugcina ukuhanjiswa okuphezulu.
I-graphene ine-modulus ephezulu kakhulu kune-substrate ye-SEBS. Nangona ubukhulu obusebenzayo be-graphene electrode buphantsi kakhulu kunobo be-substrate, ukuqina kwe-graphene kuphinda ubukhulu bayo bufana nobo be-substrate (43, 44), nto leyo ebangela isiphumo esiphakathi se-rigid-island. Silinganise ukuguquguquka kwe-graphene enobukhulu obuyi-1-nm kwi-substrate ye-SEBS (jonga Izixhobo ezongezelelweyo ukuze ufumane iinkcukacha). Ngokweziphumo zokulinganisa, xa i-20% strain isetyenziswa kwi-substrate ye-SEBS ngaphandle, i-strain ephakathi kwi-graphene yi-~6.6% (Umzobo 4J kunye nomzobo S13D), nto leyo ehambelana nokuqwalaselwa kovavanyo (jonga umfanekiso S13). Sithelekise i-strain kwiindawo ze-graphene ezineepateni kunye neendawo ze-substrate sisebenzisa i-optical microscopy kwaye safumanisa ukuba i-strain kwindawo ye-substrate iphindwe kabini ubuncinane kune-strain kwindawo ye-graphene. Oku kubonisa ukuba i-strain esetyenziswa kwiipateni ze-graphene electrode inokuthintelwa kakhulu, yenze iziqithi eziqinileyo ze-graphene phezu kwe-SEBS (26, 43, 44).
Ngoko ke, amandla ee-electrode ze-MGG okugcina umbane ophezulu phantsi koxinzelelo oluphezulu kunokwenzeka ukuba anikwe amandla ziindlela ezimbini eziphambili: (i) Ii-scrolls zinokudibanisa iindawo ezidityanisiweyo ukuze kugcinwe indlela yokuqhuba umbane, kwaye (ii) amaphepha e-graphene anee-layer/i-elastomer anokutyibilika phezu komnye nomnye, nto leyo ebangela ukuba uxinzelelo lunciphe kwii-electrode ze-graphene. Kwiileya ezininzi ze-graphene ezidluliselweyo kwi-elastomer, iileya azinamatheli ngokuqinileyo omnye komnye, nto leyo enokutyibilika ngenxa yoxinzelelo (27). Ii-scrolls zonyusa nobunzima beeleya ze-graphene, nto leyo enokunceda ukwandisa ukwahlukana phakathi kweeleya ze-graphene kwaye ngaloo ndlela ivumele ukutyibilika kweeleya ze-graphene.
Izixhobo ze-all-carbon zilandelwa ngomdla ngenxa yeendleko eziphantsi kunye nomthamo ophezulu. Kwimeko yethu, ii-transistors ze-all-carbon zenziwe kusetyenziswa isango le-graphene elisezantsi, umthombo we-graphene ophezulu/uqhagamshelwano lokukhupha, i-semiconductor ye-CNT ehleliweyo, kunye ne-SEBS njenge-dielectric (Umzobo 5A). Njengoko kubonisiwe kumzobo 5B, isixhobo se-all-carbon esine-CNTs njengomthombo/ukukhupha kunye nesango (isixhobo esisezantsi) asibonakali ngakumbi kunesixhobo esinee-electrode ze-graphene (isixhobo esiphezulu). Oku kungenxa yokuba iinethiwekhi ze-CNT zifuna ubukhulu obukhulu kwaye, ngenxa yoko, ukudluliselwa kwe-optical okuphantsi ukufezekisa ukumelana kwamaphepha okufana nokwe-graphene (umzobo S4). Umfanekiso 5 (C kunye no-D) ubonisa ii-curve zokudlulisa kunye neziphumo ezimeleyo ngaphambi koxinzelelo lwe-transistor eyenziwe ngee-electrode ze-MGG ze-bilayer. Ububanzi betshaneli kunye nobude be-transistor engaxineneyo yayiyi-800 kunye ne-100 μm, ngokwahlukeneyo. Umlinganiselo wokuvula/ukucima olinganisiweyo mkhulu kune-103 nge-currents ezivuliweyo nezivaliweyo kumanqanaba e-10−5 kunye ne-10−8 A, ngokwahlukeneyo. I-output curve ibonisa iindlela ezifanelekileyo zokulinganisa umgca kunye ne-saturation kunye nokuxhomekeka okucacileyo kwe-gate-voltage, okubonisa unxibelelwano olufanelekileyo phakathi kwe-CNTs kunye nee-graphene electrodes (45). Ukumelana noqhagamshelwano ngee-graphene electrodes kubonwe kuphantsi kunoko nge-evaporated Au film (jonga umfanekiso S14). Ukunyakaza kokugcwalisa kwe-transistor eyolulwayo malunga ne-5.6 cm2/Vs, kufana noko kwe-polymer-sorted CNT transistors ezifanayo kwi-rigid Si substrates ezine-300-nm SiO2 njengomaleko we-dielectric. Ukuphuculwa okungakumbi kokuhamba kunokwenzeka nge-optimal tube density kunye nezinye iintlobo zee-tubes (46).
(A) Iskimu se-transistor esolulwayo esekelwe kwi-graphene. Ii-SWNT, ii-nanotubes zekhabhoni ezinodonga olunye. (B) Umfanekiso wee-transistor ezolulwayo ezenziwe ngee-electrodes ze-graphene (phezulu) kunye nee-electrodes ze-CNT (ezantsi). Umahluko ekukhanyeni uyabonakala ngokucacileyo. (C kunye no-D) Ii-curve zokudlulisa kunye neziphumo ze-transistor esekelwe kwi-graphene kwi-SEBS ngaphambi koxinzelelo. (E kunye no-F) Ii-curve zokudlulisa, umbane ovuliweyo nocinywayo, umlinganiselo wokuvula/ukucima, kunye nokuhamba kwe-transistor esekelwe kwi-graphene kwiintlobo ezahlukeneyo.
Xa isixhobo esicacileyo, esinekhabhoni yonke sasisoluliwe kwicala elihambelana necala lokuthutha itshaja, ukuwohloka okuncinci kwabonwa ukuya kuthi ga kwi-120% yoxinzelelo. Ngexesha lokusoluliwe, ukushukuma kwehla ngokuqhubekayo ukusuka kwi-5.6 cm2/Vs kuxinzelelo lwe-0% ukuya kwi-2.5 cm2/Vs kuxinzelelo lwe-120% (Umzobo 5F). Sikwathelekise ukusebenza kwe-transistor ngobude beendlela ezahlukeneyo (jonga itheyibhile S1). Okuphawulekayo kukuba, kuxinzelelo olukhulu njenge-105%, zonke ezi transistor zisabonisa umlinganiselo ophezulu wokuvula/ukucima ( >103) kunye nokushukuma ( >3 cm2/Vs). Ukongeza, sishwankathele wonke umsebenzi wakutshanje kwiitransistor zekhabhoni yonke (jonga itheyibhile S2) (47–52). Ngokuphucula ukwenziwa kwesixhobo kwi-elastomers kunye nokusebenzisa iiMGG njengee-contacts, iitransistor zethu zekhabhoni yonke zibonisa ukusebenza okuhle ngokubhekiselele ekushukumeni kunye ne-hysteresis kunye nokuba zisoluliwe kakhulu.
Njengesicelo se-transistor ecacileyo neyolulwayo, siyisebenzise ukulawula ukutshintshwa kwe-LED (Umzobo 6A). Njengoko kubonisiwe kwiFig. 6B, i-LED eluhlaza ibonakala ngokucacileyo ngesixhobo se-all-carbon esolulwayo esibekwe ngqo ngaphezulu. Ngelixa isolulwa ukuya kwi-~100% (Umzobo 6, C kunye no-D), ubukhali bokukhanya kwe-LED abutshintshi, nto leyo ehambelana nokusebenza kwe-transistor echazwe apha ngasentla (jonga imuvi i-S1). Le yingxelo yokuqala yeeyunithi zolawulo ezolulwayo ezenziwe kusetyenziswa ii-electrode ze-graphene, ezibonisa ithuba elitsha le-electronics ezolulwayo ze-graphene.
(A) Isekethe ye-transistor yokuqhuba i-LED. GND, emhlabeni. (B) Umfanekiso we-transistor ye-all-carbon eyolulwayo necacileyo kuxinzelelo lwe-0% ebekwe ngaphezulu kwe-LED eluhlaza. (C) I-transistor ye-all-carbon ecacileyo neyolulwayo esetyenziselwa ukutshintsha i-LED ifakelwe ngaphezulu kwe-LED kuxinzelelo lwe-0% (ekhohlo) kunye noxinzelelo lwe-~100% (ekunene). Iintolo ezimhlophe zikhomba njengeempawu ezimthubi kwisixhobo ukubonisa utshintsho lomgama olusolulwayo. (D) Umbono osecaleni we-transistor eyolulwayo, kunye ne-LED ityhalelwe kwi-elastomer.
Ukuqukumbela, siye sayila isakhiwo se-graphene esibonakalayo esigcina ukuhanjiswa okuphezulu phantsi kweentlobo ezinkulu njengee-electrode ezinokolulwa, ezivunywa yi-graphene nanoscrolls phakathi kweeleya ze-graphene ezihlanganisiweyo. Ezi zakhiwo ze-electrode ze-MGG ze-bi- kunye ne-trilayer kwi-elastomer zinokugcina i-21 kunye ne-65%, ngokulandelelana, ye-0% yokuhanjiswa koxinzelelo kwi-strain ephezulu njenge-100%, xa kuthelekiswa nokulahleka okupheleleyo kokuqhuba kwi-5% yoxinzelelo kwie-electrode ze-graphene eziqhelekileyo ze-monolayer. Iindlela ezongezelelweyo zokuqhuba ze-graphene scrolls kunye nokusebenzisana okubuthathaka phakathi kweeleya ezidluliselweyo kuncedisa kuzinzo oluphezulu lokuqhuba phantsi koxinzelelo. Sisebenzise ngakumbi esi sakhiwo se-graphene ukwenza ii-transistors ezinokolulwa ze-all-carbon. Okwangoku, le yeyona transistor isekelwe kwi-graphene enokolulwa kakhulu enokubonakala ngcono ngaphandle kokusebenzisa i-buckling. Nangona olu phononongo lwenziwe ukuze kuvunyelwe i-graphene kwii-electronics ezinokolulwa, sikholelwa ukuba le ndlela inokwandiswa kwezinye izinto ze-2D ukuze kuvunyelwe ii-electronics ze-2D ezinokolulwa.
I-graphene ye-CVD yendawo enkulu ikhuliswe kwiifoyile ze-Cu ezixhonyiweyo (99.999%; i-Alfa Aesar) phantsi koxinzelelo olungaguqukiyo lwe-0.5 mtorr kunye ne-50–SCCM (isentimitha ye-cubic esemgangathweni ngomzuzu) i-CH4 kunye ne-20–SCCM H2 njengezinto ezingaphambili kwi-1000°C. Amacala omabini efoyile ye-Cu agqunywe yi-monolayer graphene. Umaleko omncinci we-PMMA (2000 rpm; A4, Microchem) wagqunywa nge-spin-coating kwelinye icala lefoyile ye-Cu, wenza isakhiwo se-PMMA/G/Cu foil/G. Emva koko, yonke ifilimu yacwiliswa kwisisombululo se-0.1 M ammonium persulfate [(NH4)2S2O8] malunga neeyure ezi-2 ukuze kususwe ifoyile ye-Cu. Ngexesha lale nkqubo, i-graphene engakhuselekanga yaqala yakrazula kwimida yeenkozo yaze yasongwa yaba yimisongo ngenxa yoxinzelelo lomphezulu. Imisongo yaqhotyoshelwa kwifilimu ye-graphene ephezulu exhaswa yi-PMMA, yenza imisongo ye-PMMA/G/G. Emva koko iifilimu zahlanjwa ngamanzi acocekileyo amaxesha amaninzi zaza zabekwa kwindawo ekujoliswe kuyo, njenge-SiO2/Si eqinileyo okanye iplastiki. Kwakuba nje ifilimu eqhotyoshelweyo yomile kwindawo ekusetyenzwa kuyo, isampuli yacwiliswa ngokulandelelana kwi-acetone, i-1:1 acetone/IPA (isopropyl alcohol), kunye ne-IPA imizuzwana engama-30 nganye ukuze kususwe i-PMMA. Iifilimu zafudunyezwa kwi-100°C imizuzu eli-15 okanye zigcinwe kwindawo yokuthambisa ubusuku bonke ukuze kususwe ngokupheleleyo amanzi avalelekileyo ngaphambi kokuba kudluliselwe omnye umaleko we-G/G scroll kuyo. Eli nyathelo yayikukuphepha ukususwa kwefilimu ye-graphene kwi-substrate kunye nokuqinisekisa ukugqunywa ngokupheleleyo kwe-MGGs ngexesha lokukhululwa komaleko we-PMMA carrier.
Imo yesakhiwo seMGG ibonwe kusetyenziswa i-optical microscope (Leica) kunye ne-scanning electron microscope (1 kV; FEI). I-atomic force microscope (Nanoscope III, Digital Instrument) isetyenzisiwe kwimo yokuthepha ukuze kubonwe iinkcukacha ze-G scrolls. Ukubonakala kwefilimu kuhlolwe yi-ultraviolet-visible spectrometer (Agilent Cary 6000i). Kwiimvavanyo xa i-strain yayikwicala elithe nkqo lokuhamba kombane, i-photolithography kunye ne-O2 plasma zisetyenzisiwe ukupeyinta izakhiwo ze-graphene zibe yimicu (~300 μm ububanzi kunye ~2000 μm ubude), kwaye ii-Au (50 nm) electrodes zibekwe ngobushushu kusetyenziswa i-shadow masks kuzo zombini iziphelo zecala elide. Emva koko imicu yegraphene yafakwa kwi-elastomer ye-SEBS (~2 cm ububanzi kunye ~5 cm ubude), kunye ne-axis ende yemicu ehambelana necala elifutshane le-SEBS ilandelwa yi-BOE (buffered oxide etch) (HF:H2O 1:6) etching kunye ne-eutectic gallium indium (EGaIn) njengee-contacts zombane. Kwiimvavanyo zoxinzelelo oluhambelanayo, izakhiwo zegraphene ezingafakwanga ipateni (~5 × 10 mm) zadluliselwa kwi-substrates ze-SEBS, kunye nee-axes ezinde ezihambelana necala elide le-substrate ye-SEBS. Kuzo zombini iimeko, yonke i-G (ngaphandle kwe-G scrolls)/SEBS yoluliwe ecaleni elide le-elastomer kwisixhobo esenziwe ngesandla, kwaye endaweni yoko, silinganise utshintsho lwazo lokumelana phantsi koxinzelelo kwisikhululo se-probe nge-semiconductor analyzer (Keithley 4200-SCS).
Iitransistor ze-all-carbon ezithambileyo nezicacileyo kwi-substrate elastiki zenziwe ngezi nkqubo zilandelayo ukuze kuthintelwe umonakalo we-organic solvent kwi-polymer dielectric kunye ne-substrate. Izakhiwo ze-MGG zidluliselwe kwi-SEBS njengee-electrodes zesango. Ukuze kufunyanwe umaleko we-polymer dielectric ofanayo (2 μm ubukhulu), isisombululo se-SEBS toluene (80 mg/ml) safakwa kwi-octadecyltrichlorosilane (OTS)–modified SiO2/Si substrate kwi-1000 rpm ngomzuzu o-1. Ifilimu ye-dielectric ebhityileyo inokudluliselwa ngokulula ukusuka kumphezulu we-hydrophobic OTS ukuya kwi-substrate ye-SEBS egqunywe yi-graphene elungisiweyo. I-capacitor ingenziwa ngokubeka i-electrode ephezulu ye-liquid-metal (EGaIn; Sigma-Aldrich) ukumisela i-capacitance njengomsebenzi woxinzelelo kusetyenziswa i-LCR (inductance, capacitance, resistance) meter (Agilent). Elinye icandelo le-transistor laliquka ii-polymer-sorted semiconducting CNTs, kulandela iinkqubo ezichazwe ngaphambili (53). I-electrod yomthombo/yokukhupha enepateni yenziwe kwi-substrates eziqinileyo ze-SiO2/Si. Emva koko, la macandelo mabini, i-dielectric/G/SEBS kunye ne-CNTs/enepateni ye-G/SiO2/Si, adityaniswa, aze afakwe kwi-BOE ukuze kususwe i-substrate eqinileyo ye-SiO2/Si. Ngoko ke, ii-transistors ezicacileyo nezinokululwa zenziwe. Uvavanyo lombane phantsi koxinzelelo lwenziwe kwiseti yokulula ngesandla njengendlela ekhankanyiweyo ngasentla.
Izinto ezongezelelweyo zeli nqaku zifumaneka apha http://advances.sciencemag.org/cgi/content/full/3/9/e1700159/DC1
umfanekiso. S1. Imifanekiso ye-optical microscopy ye-monolayer MGG kwi-SiO2/Si substrates kwiindlela ezahlukeneyo zokukhulisa.
umfanekiso. S4. Uthelekiso lwee-two-probe sheet resistances kunye ne-transmittances @550 nm ze-mono-, bi- kunye ne-trilayer plain graphene (izikwere ezimnyama), i-MGG (izangqa ezibomvu), kunye ne-CNTs (unxantathu oluhlaza okwesibhakabhaka).
umfanekiso. S7. Utshintsho oluqhelekileyo lokumelana kwe-mono- kunye ne-bilayer MGGs (mnyama) kunye ne-G (bomvu) phantsi kwe-~1000 cyclic strain elayisha ukuya kuthi ga kwi-40 kunye ne-90% parallel strain, ngokulandelanayo.
umfanekiso. S10. Umfanekiso we-SEM we-trilayer MGG kwi-elastomer ye-SEBS emva koxinzelelo, obonisa umjikelo omde wokuskrola phezu kwemifantu eliqela.
umfanekiso. S12. Umfanekiso we-AFM we-trilayer MGG kwi-elastomer ye-SEBS ebhityileyo kakhulu kwi-20% yoxinzelelo, ebonisa ukuba umqulu unqumle phezu komfantu.
Itheyibhile S1. Ukushukuma kwee-transistors ze-bilayer MGG–single-walled carbon nanotube kwiindlela ezahlukeneyo zobude ngaphambi nasemva koxinzelelo.
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QAPHELA: Sicela idilesi yakho ye-imeyile kuphela ukuze umntu ocebisa iphepha azi ukuba ubufuna ukuba ayibone, kwaye ayiyo-junk mail. Asibambi nayiphi na idilesi ye-imeyile.
Lo mbuzo ngowokuvavanya ukuba ungumntu ondwendweleyo okanye awunguye, kwaye uthintele ukuthunyelwa kwe-spam ngokuzenzekelayo.
NguNan 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
NguNan 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
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