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Amafilimu e-Nanoscale graphite (NGFs) angama-nanomaterials aqinile angakhiqizwa ngokufakwa komhwamuko wamakhemikhali, kodwa imibuzo isasele mayelana nokudluliswa kwawo kalula nokuthi i-surface morphology ikuthinta kanjani ukusetshenziswa kwawo emishinini yesizukulwane esilandelayo. Lapha sibika ukukhula kwe-NGF ezinhlangothini zombili ze-polycrystalline nickel foil (indawo engu-55 cm2, ukujiya mayelana ne-100 nm) nokudluliswa kwayo okungenayo i-polymer (ngaphambili nangemuva, indawo efika ku-6 cm2). Ngenxa ye-morphology ye-catalyst foil, amafilimu amabili ekhabhoni ayahluka ngezakhiwo zawo ezingokomzimba nezinye izici (ezifana nokuhwaqazeka kwendawo). Sibonisa ukuthi ama-NGF anengemuva elimangelengele afaneleka kahle ukutholwa kwe-NO2, kuyilapho ama-NGF abushelelezi futhi aqhuba kakhudlwana ohlangothini olungaphambili (2000 S/cm, ukumelana neshidi - 50 ohms/m2) angaba ama-conductor asebenzayo. isiteshi noma i-electrode yeseli yelanga (njengoba idlulisa u-62% wokukhanya okubonakalayo). Sekukonke, ukukhula okuchaziwe kanye nezinqubo zokuthutha zingasiza ekuboneni i-NGF njengenye into yekhabhoni yezinhlelo zokusebenza zobuchwepheshe lapho amafilimu e-graphene nama-micron-thick graphite engafaneleki.
I-graphite yinto esetshenziswa kakhulu yezimboni. Ngokuphawulekayo, i-graphite inezici zokuminyana okuphansi uma kuqhathaniswa kanye nokuhamba okuphezulu kwe-thermal endizeni kanye nokuhamba kukagesi, futhi izinzile kakhulu ezindaweni ezishisayo namakhemikhali1,2. I-Flake graphite iyinto eyaziwayo yokuqala yocwaningo lwe-graphene3. Uma icutshungulwa ibe amafilimu amancane, ingasetshenziswa ezinhlelweni eziningi ezahlukene, okuhlanganisa amasinki okushisa ezinto zikagesi ezifana nama-smartphones4,5,6,7, njengento esebenzayo kuzinzwa8,9,10 kanye nokuvikela ukuphazamiseka kwe-electromagnetic11. 12 namafilimu e-lithography ku-ultraviolet13,14 eyedlulele, eqhuba iziteshi kumaseli elanga15,16. Kuzo zonke lezi zinhlelo zokusebenza, kungaba inzuzo enkulu uma izindawo ezinkulu zamafilimu e-graphite (ama-NGF) ezinobukhulu obulawulwa ku-nanoscale <100 nm zingakhiqizwa futhi zihanjiswe kalula.
Amafilimu e-graphite akhiqizwa ngezindlela ezihlukahlukene. Kwesinye isikhathi, ukushumeka nokwandiswa okulandelwa ukukhishwa kwasetshenziswa ukukhiqiza ama-graphene flakes10,11,17. Ama-flakes kufanele aphinde acutshungulwe abe amafilimu anogqinsi oludingekayo, futhi ngokuvamile kuthatha izinsuku ezimbalwa ukukhiqiza amashidi aminyene egraphite. Enye indlela iwukuqala ngama-graphable aqinile ama-precursors. Embonini, amashidi ama-polymers afakwa nge-carbonized (ku-1000-1500 ° C) bese enziwa i-graphitized (ku-2800-3200 ° C) ukuze akhe izinto ezigqinsiwe ezakhiwe kahle. Nakuba izinga lalawa mafilimu liphezulu, ukusetshenziswa kwamandla kubalulekile1,18,19 futhi ukujiya okuncane kukhawulelwe kuma-microns ambalwa1,18,19,20.
I-Catalytic chemical vapor deposition (CVD) iyindlela eyaziwa kakhulu yokukhiqiza amafilimu e-graphene kanye ne-ultrathin graphite (<10 nm) anekhwalithi ephezulu yesakhiwo nezindleko ezizwakalayo21,22,23,24,25,26,27. Nokho, uma kuqhathaniswa nokukhula kwamafilimu e-graphene kanye ne-ultrathin graphite28, ukukhula kwendawo enkulu kanye/noma ukusetshenziswa kwe-NGF kusetshenziswa i-CVD kuhlolwa kancane11,13,29,30,31,32,33.
Amafilimu e-graphene nama-graphite akhule ku-CVD ngokuvamile adinga ukudluliselwa kuma-substrates asebenzayo34. Lokhu kudluliselwa kwefilimu emincane kuhilela izindlela ezimbili eziyinhloko35: (1) ukudluliswa kwe-non-etch36,37 kanye (2) nokudluliswa kwamakhemikhali okumanzi okusekelwe etch (i-substrate esekelwe)14,34,38. Indlela ngayinye inezinzuzo kanye nokubi okuthile futhi kufanele ikhethwe kuye ngokuthi isetshenziswa kanjani, njengoba kuchazwe kwenye indawo35,39. Kumafilimu e-graphene/graphite akhuliswe kuma-catalytic substrates, ukudluliswa ngezinqubo zamakhemikhali ezimanzi (lapho i-polymethyl methacrylate (PMMA) iwusendlalelo sokusekela esisetshenziswa kakhulu) ihlala iyinketho yokuqala13,30,34,38,40,41,42. Wena et al. Kwashiwo ukuthi ayikho i-polymer esetshenziselwa ukudluliswa kwe-NGF (usayizi wesampula cishe u-4 cm2) i-25,43, kodwa akukho mininingwane enikeziwe mayelana nokuzinza kwesampula kanye / noma ukuphatha ngesikhathi sokudlulisa; Izinqubo zamakhemikhali amanzi zisebenzisa ama-polymers zihlanganisa izinyathelo ezimbalwa, okuhlanganisa ukusetshenziswa nokususwa okulandelayo komhlatshelo we-polymer layer30,38,40,41,42. Le nqubo inemibi: isibonelo, izinsalela ze-polymer zingashintsha izakhiwo zefilimu ekhulile38. Ukucubungula okwengeziwe kungasusa i-polymer esele, kodwa lezi zinyathelo ezengeziwe zandisa izindleko kanye nesikhathi sokukhiqizwa kwefilimu38,40. Ngesikhathi sokukhula kwe-CVD, ungqimba lwe-graphene alufakwanga kuphela ohlangothini lwangaphambili lwe-catalyst foil (uhlangothi olubheke ukugeleza kwe-steam), kodwa nangemuva kwayo. Kodwa-ke, lokhu okugcina kubhekwa njengomkhiqizo wemfucuza futhi kungasuswa ngokushesha nge-plasma38,41 ethambile. Ukugaywa kabusha le filimu kungasiza ekwandiseni isivuno, ngisho noma ingeyekhwalithi ephansi kunefilimu yekhabhoni yobuso.
Lapha, sibika ukulungiswa kokukhula kwe-NGF ye-wafer-scale ene-bifacial yekhwalithi ephezulu ye-polycrystalline nickel foil nge-CVD. Kwahlolisiswa ukuthi ukugoqana kwendawo engaphambili nengemuva yefoyili kuyithinta kanjani indlela i-morphology nesakhiwo se-NGF. Siphinde futhi sibonise ukudluliswa kwe-NGF kwe-polymer ngendlela engabizi kakhulu futhi evumelana nemvelo isuka ezinhlangothini zombili ze-nickel foil iye kuma-substrates asebenza ngezindlela eziningi futhi sibonise ukuthi amafilimu angaphambili nangemuva afaneleka kanjani ukusetshenziswa okuhlukahlukene.
Izigaba ezilandelayo zixoxa ngogqinsi oluhlukene lwefilimu ye-graphite kuye ngenani lezendlalelo ze-graphene ezistakiwe: (i) i-graphene yesendlalelo esisodwa (SLG, ungqimba olu-1), (ii) i-graphene yesendlalelo esincane (FLG, < izendlalelo ezingu-10), (iii) i-graphene enezingqimba eziningi ( MLG, 10-30 izendlalelo) kanye (iv) NGF (~300 izendlalelo). Lesi sakamuva siwugqinsi oluvame kakhulu oluvezwa njengephesenti lendawo (cishe indawo engu-97% nge-100 µm2)30. Yingakho yonke ifilimu ibizwa nje ngokuthi i-NGF.
Ama-polycrystalline nickel foil asetshenziselwa ukuhlanganiswa kwamafilimu e-graphene nawe-graphite anokwakheka okuhlukile ngenxa yokwenziwa kwawo kanye nokucutshungulwa kwawo okulandelayo. Sisanda kubika ucwaningo lokuthuthukisa inqubo yokukhula ye-NGF30. Sibonisa ukuthi amapharamitha enqubo afana nesikhathi sokukhipha kanye nokucindezela kwegumbi phakathi nesigaba sokukhula adlala indima ebalulekile ekutholeni ama-NGF okuqina okufanayo. Lapha, siphinde saphenya ngokukhula kwe-NGF endaweni engaphambili epholishiwe (FS) nasezindaweni ezingemuva ezingapholishiwe (BS) ze-nickel foil (Fig. 1a). Izinhlobo ezintathu zamasampuli i-FS ne-BS zahlolwa, ezisohlwini kuThebula 1. Lapho kuhlolwa okubonakalayo, ukukhula okufanayo kwe-NGF ezinhlangothini zombili ze-nickel foil (NiAG) kungabonwa ngokushintsha kombala wenqwaba ye-Ni substrate kusukela kusici sesiliva sensimbi. grey kumbala ompunga we-matte (Umfanekiso 1a); izilinganiso ezincane ziqinisekisiwe (Fig. 1b, c). I-spectrum ye-Raman evamile ye-FS-NGF ebonwa endaweni ekhanyayo futhi ekhonjiswa ngemicibisholo ebomvu, eluhlaza okwesibhakabhaka kanye newolintshi kuMfanekiso 1b iboniswa kuMfanekiso 1c. Isici seziqongo ze-Raman zegraphite G (1683 cm−1) kanye ne-2D (2696 cm−1) ziqinisekisa ukukhula kwe-NGF ecwebe kakhulu (Fig. 1c, Table SI1). Kuyo yonke ifilimu, kubonwe ukugqama kwe-Raman spectra with intensity ratio (I2D/IG) ~0.3, kuyilapho i-Raman spectra ene-I2D/IG = 0.8 yayingavamile ukubonwa. Ukungabikho kweziqongo ezingalungile (D = 1350 cm-1) kuyo yonke ifilimu kubonisa izinga eliphezulu lokukhula kwe-NGF. Imiphumela efanayo ye-Raman itholwe kusampula ye-BS-NGF (Umfanekiso SI1 a no-b, Ithebula SI1).
Ukuqhathaniswa kwe-NiAG FS- ne-BS-NGF: (a) Isithombe sesampula evamile ye-NGF (NiAG) ebonisa ukukhula kwe-NGF esikalini esiyi-wafer (55 cm2) kanye nomphumela wamasampula e-foil we-BS- kanye ne-FS-Ni, (b) FS-NGF Izithombe/ I-Ni etholwe ngesibonakhulu esibonakalayo, (c) i-spectra evamile ye-Raman eqoshwe ezindaweni ezihlukene kuphaneli b, (d, f) Izithombe ze-SEM ngokukhuliswa okuhlukile ku-FS-NGF/Ni, (e, g) izithombe ze-SEM ekukhulisweni okuhlukile Imisa i-BS -NGF/Ni. Umcibisholo oluhlaza okwesibhakabhaka ubonisa isifunda se-FLG, umcibisholo owolintshi ubonisa isifunda se-MLG (eduze nesifunda se-FLG), umcibisholo obomvu ubonisa isifunda se-NGF, futhi umcibisholo we-magenta ubonisa ukugoqa.
Njengoba ukukhula kuncike ebukhulu be-substrate yokuqala, ubukhulu bekristalu, ukuma, kanye nemingcele yokusanhlamvu, ukufeza ukulawulwa okunengqondo kokuqina kwe-NGF ezindaweni ezinkulu kuhlala kuyinselele20,34,44. Lolu cwaningo lusebenzise okuqukethwe esikushicilele ngaphambilini30. Le nqubo ikhiqiza indawo ekhanyayo engu-0.1 kuya ku-3% nge-100 µm230 ngayinye. Ezigabeni ezilandelayo, sethula imiphumela yazo zombili izinhlobo zezifunda. Izithombe ze-SEM zokukhuliswa okuphezulu zibonisa ukuba khona kwezindawo ezimbalwa zokugqama okugqamile nhlangothi zombili (Fig. 1f,g), okubonisa ukuba khona kwezifunda ze-FLG ne-MLG30,45. Lokhu kuphinde kwaqinisekiswa ukuhlakazeka kwe-Raman (Fig. 1c) kanye nemiphumela ye-TEM (okuxoxwe ngayo kamuva esigabeni esithi "FS-NGF: isakhiwo kanye nezakhiwo"). Izifunda ze-FLG kanye ne-MLG eziqashelwe kumasampula e-FS- kanye ne-BS-NGF/Ni (i-NGF yangaphambili nangemuva etshalwe ku-Ni) kungenzeka ukuthi ikhule ezinhlangeni ezinkulu ze-Ni(111) ezakhiwe ngesikhathi sokuhlanganiswa kwangaphambilini22,30,45. Ukugoqa kwabonwa nhlangothi zombili (Fig. 1b, ephawulwe ngemicibisholo onsomi). Lawa mafolda avame ukutholakala kumafilimu e-graphene nama-graphite akhule e-CVD ngenxa yomehluko omkhulu ku-coefficient yokwanda okushisayo phakathi kwegraphite ne-nickel substrate30,38.
Isithombe se-AFM siqinisekisile ukuthi isampula ye-FS-NGF yayithambile kunesampula ye-BS-NGF (Umfanekiso SI1) (Umfanekiso SI2). Impande isho isikwele (RMS) amavelu amagwebu e-FS-NGF/Ni (Fig. SI2c) kanye ne-BS-NGF/Ni (Fig. SI2d) angu-82 kanye no-200 nm, ngokulandelanayo (akalwa endaweni engu-20 × 20 um2). Ubulukhuni obuphakeme bungaqondwa ngokusekelwe ekuhlaziyweni kwendawo ye-nickel (NiAR) foil kusimo esitholiwe (Umfanekiso SI3). Izithombe ze-SEM ze-FS kanye ne-BS-NiAR ziboniswa kuMifanekiso SI3a–d, ebonisa i-morphology yangaphezulu ehlukene: ucwecwe olupholishiwe lwe-FS-Ni lunezinhlayiya eziyindilinga ezinosayizi we-nano- kanye ne-micron, kuyilapho ucwecwe lwe-BS-Ni olungapholishiwe lubonisa iledi lokukhiqiza. njengezinhlayiya ezinamandla aphezulu. futhi wenqabe. Izithombe ezicacayo eziphansi neziphezulu ze-nickel foil (NiA) efakiwe ziboniswa kuMfanekiso SI3e–h. Kulezi zibalo, singabona ukuba khona kwezinhlayiya zenikeli ezinosayizi omncane we-micron ezinhlangothini zombili ze-nickel foil (Fig. SI3e–h). Izinhlamvu ezinkulu zingase zibe nokuma kwe-Ni(111) ngaphezulu, njengoba kubikwe ngaphambilini30,46. Kunomehluko omkhulu ku-nickel foil morphology phakathi kwe-FS-NiA ne-BS-NiA. Ubulukhuni obuphakeme be-BS-NGF/Ni bubangelwa indawo engapholishiwe ye-BS-NiAR, indawo engaphezulu ehlala ilukhuni kakhulu ngisho nangemva kokuhushulwa (Umfanekiso SI3). Lolu hlobo lwezimpawu ezingaphezulu ngaphambi kwenqubo yokukhula luvumela ukushuba kwamafilimu e-graphene nawe-graphite ukuthi kulawulwe. Kufanele kuqashelwe ukuthi i-substrate yasekuqaleni ibe nokuhlelwa kabusha kokusanhlamvu phakathi nokukhula kwe-graphene, okwehlise kancane usayizi wokusanhlamvu futhi kwakhuphula kancane ubulukhuni bendawo engaphansi uma kuqhathaniswa ne-foil ehlanganisiwe nefilimu ye-catalyst22.
Ukulungisa kahle ubugebenga bendawo engaphansi, isikhathi sokuhlanganisa (usayizi wokusanhlamvu)30,47 nokulawula ukukhululwa43 kuzosiza ukunciphisa ukufana kogqinsi kwesifunda kwe-NGF kusikali esingu-µm2 kanye/noma ngisho ne-nm2 (okungukuthi, ukuhluka kogqinsi kwama-nanometer ambalwa). Ukuze kulawulwe ubulukhuni obungaphezulu be-substrate, izindlela ezinjengokupholisha nge-electrolytic kocwecwe lwe-nickel oluwumphumela lungabhekwa48. Ucwecwe lwe-nickel olulungisiwe lungabese lufakwa ezingeni lokushisa eliphansi (< 900 °C) 46 kanye nesikhathi (< 5 min) ukugwema ukwakheka kwezinhlamvu ezinkulu ze-Ni(111) (okunenzuzo ekukhuleni kwe-FLG).
I-SLG ne-FLG graphene ayikwazi ukumelana nokushuba kwendawo yama-asidi namanzi, okudinga izendlalelo zokusekela ngomshini phakathi nezinqubo zokudlulisa amakhemikhali ezimanzi22,34,38. Ngokuphambene nokudluliswa kwamakhemikhali okumanzi kwe-graphene38 ye-polymer-ungqimba olulodwa, sithole ukuthi izinhlangothi zombili ze-NGF ekhulile zingadluliswa ngaphandle kokusekelwa kwe-polymer, njengoba kuboniswe ku-Figure 2a (bona Umfanekiso we-SI4a ukuze uthole imininingwane eyengeziwe). Ukudluliswa kwe-NGF endaweni engaphansi enikeziwe kuqala ngokushumeka okumanzi kwefilimu engaphansi ye-Ni30.49. Amasampuli asekhulile e-NGF/Ni/NGF abekwe ngobusuku obubodwa ku-15 mL ka-70% HNO3 oxutshwe no-600 mL wamanzi e-deionized (DI). Ngemva kokuba i-Ni foil isihlakazwe ngokuphelele, i-FS-NGF ihlala isicaba futhi intanta phezu koketshezi, njengesampula ye-NGF/Ni/NGF, kuyilapho i-BS-NGF icwiliswa emanzini (Fig. 2a,b). I-NGF ehlukanisiwe yabe isidluliswa isuka kubhekha owodwa owawunamanzi ahlanzekile enziwe i-deionized yayiswa kwelinye futhi i-NGF ehlukanisiwe yagezwa kahle, iphindaphinda izikhathi ezine kuya kweziyisithupha ngesitsha sengilazi esiyi-concave. Ekugcineni, i-FS-NGF ne-BS-NGF zafakwa ku-substrate oyifunayo (Fig. 2c).
Inqubo yokudlulisa amakhemikhali amanzi angenayo i-polymer ye-NGF etshalwe ku-nickel foil: (a) Umdwebo wokugeleza kwenqubo (bona Umfanekiso SI4 ukuze uthole imininingwane eyengeziwe), (b) Isithombe sedijithali se-NGF ehlukanisiwe ngemva kwe-Ni etching (amasampula angu-2), (c) Isibonelo se-FS - kanye ne-BS-NGF idluliselwe ku-SiO2/Si substrate, (d) FS-NGF idluliselwe ku-opaque polymer substrate, (e) BS-NGF isuka kusampula efanayo nephaneli d (ihlukaniswe izingxenye ezimbili), idluliselwe ephepheni legolide elicwecwe C kanye ne-Nafion (i-substrate esobala eguquguqukayo, imiphetho ephawulwe ngamakhona abomvu).
Qaphela ukuthi ukudluliswa kwe-SLG okwenziwe kusetshenziswa izindlela zokudlulisa amakhemikhali ezimanzi kudinga isikhathi sokucubungula esiphelele samahora angu-20-24 38. Ngesu lokudlulisa lamahhala le-polymer eliboniswe lapha (Umfanekiso SI4a), sonke isikhathi sokucubungula ukudluliswa kwe-NGF sehliswe kakhulu (cishe amahora ayi-15). Inqubo iqukethe: (Isinyathelo 1) Lungiselela isixazululo sokunamathisela bese ubeka isampula kuyo (~amaminithi angu-10), bese ulinda ubusuku bonke ukuze uthole i-Ni etching (~7200 amaminithi), (Isinyathelo 2) Hlanza ngamanzi a-deionized (Isinyathelo - 3) . gcina emanzini e-deionized noma udlulisele ku-substrate eqondiwe (20 min). Amanzi avaleleke phakathi kwe-NGF kanye ne-matrix yobuningi asuswa isenzo se-capillary (kusetshenziswa iphepha lokuvala)38, bese amaconsi amanzi asele asuswa ngokomiswa kwemvelo (cishe i-30 min), futhi ekugcineni isampula yomiswa imizuzu eyi-10. iminithi kuhhavini wevacuum (10–1 mbar) at 50–90 °C (60 min) 38.
I-graphite yaziwa ngokumelana nokuba khona kwamanzi nomoya emazingeni okushisa aphezulu (≥ 200 °C)50,51,52. Sihlole amasampula sisebenzisa i-Raman spectroscopy, i-SEM, ne-XRD ngemva kokugcinwa emanzini angcolile ekamelweni lokushisa nasemabhodleleni avaliwe noma yikuphi kusukela ezinsukwini ezimbalwa kuya onyakeni owodwa (Umfanekiso SI4). Akukho ukwehliswa okubonakalayo. Umfanekiso 2c ubonisa ukuma kwamahhala kwe-FS-NGF kanye ne-BS-NGF emanzini angcolile. Siwathwebule ku-SiO2 (300 nm)/Si substrate, njengoba kubonisiwe ekuqaleni koMfanekiso 2c. Ukwengeza, njengoba kukhonjisiwe kuMfanekiso 2d,e, i-NGF eqhubekayo ingadluliselwa kuma-substrates ahlukahlukene njengama-polymers (i-Thermabright polyamide evela ku-Nexolve ne-Nafion) kanye nephepha lekhabhoni elinegolide. I-FS-NGF entantayo yabekwa kalula ku-substrate eqondiwe (Fig. 2c, d). Nokho, amasampula e-BS-NGF amakhulu kuno-3 cm2 kwakunzima ukuwaphatha lapho ecwiliswa ngokuphelele emanzini. Ngokuvamile, lapho beqala ukugoqa emanzini, ngenxa yokuphatha ngokunganaki ngezinye izikhathi baphule izingxenye ezimbili noma ezintathu (Fig. 2e). Sekukonke, sikwazile ukufeza ukudluliswa kwamahhala kwe-polymer kwe-PS- kanye ne-BS-NGF (ukudlulisa okungenamthungo okuqhubekayo ngaphandle kokukhula kwe-NGF/Ni/NGF ku-6 cm2) kumasampula afika ku-6 no-3 cm2 endaweni, ngokulandelana. Noma yiziphi izingcezu ezinkulu noma ezincane ezisele zingaba (zibonakale kalula kusixazululo sokushumeka noma emanzini akhishwe yi-deionized) ku-substrate oyifunayo (~1 mm2, Umfanekiso SI4b, bona isampula edluliselwe kugridi yethusi njengaku-“FS-NGF: Isakhiwo Nezakhiwo (okuxoxiwe ngakho) ngaphansi kokuthi “Isakhiwo Nezakhiwo”) noma gcina ukuze uzisebenzise esikhathini esizayo (Umfanekiso SI4). Ngokusekelwe kulo mbandela, silinganisela ukuthi i-NGF ingatholwa ngesivuno esingafika ku-98-99% (ngemuva kokukhula kokudluliselwa).
Amasampula okudlulisa ngaphandle kwe-polymer ahlaziywa ngokuningiliziwe. Izici ze-Surface morphological ezitholakala ku-FS- kanye ne-BS-NGF / SiO2 / Si (Fig. 2c) isebenzisa i-microscopy ye-optical (OM) ne-SEM izithombe (Fig. SI5 kanye ne-Fig. 3) ibonise ukuthi lawa masampuli adluliselwe ngaphandle kwe-micrscopy. Umonakalo obonakalayo wesakhiwo onjengemifantu, izimbobo, noma izindawo ezingasokile. Ukugoqa ku-NGF ekhulayo (Fig. 3b, d, ephawulwe ngemicibisholo ensomi) yahlala injalo ngemva kokudluliselwa. Kokubili ama-FS- kanye ne-BS-NGF akhiwe izifunda ze-FLG (izifunda ezikhanyayo ezikhonjiswa ngemicibisholo eluhlaza okwesibhakabhaka kuMfanekiso 3). Ngokumangalisayo, ngokungafani nezifunda ezimbalwa ezilimele ezivame ukubonwa ngesikhathi sokudluliselwa kwe-polymer yamafilimu e-ultrathin graphite, izifunda eziningana ze-FLG ne-MLG ezinosayizi omncane we-micron ezixhunywe ku-NGF (ezimakwe ngemicibisholo eluhlaza okwesibhakabhaka ku-Figure 3d) zidluliselwe ngaphandle kokuqhekeka noma ukuphuka (Umfanekiso 3d) . 3). . Ubuqotho bemishini baphinde baqinisekiswa kusetshenziswa izithombe ze-TEM ne-SEM ze-NGF ezidluliselwe kumagridi ethusi e-lace-carbon, njengoba kuxoxiwe kamuva (“FS-NGF: Isakhiwo Nezakhiwo”). I-BS-NGF/SiO2/Si edlulisiwe ilukhuni kune-FS-NGF/SiO2/Si enamanani e-rms engu-140 nm no-17 nm, ngokulandelana, njengoba kukhonjisiwe kuMfanekiso SI6a no-b (20 × 20 μm2). Inani le-RMS le-NGF elidluliselwe ku-SiO2/Si substrate (RMS <2 nm) liphansi kakhulu (cishe izikhathi ezingu-3) kunalelo le-NGF elikhule ku-Ni (Figure SI2), okubonisa ukuthi ubulukhuni obengeziwe bungase buhambisane ne-Ni surface. Ngaphezu kwalokho, izithombe ze-AFM ezenziwe emaphethelweni e-FS- kanye namasampula e-BS-NGF/SiO2/Si abonise ubukhulu be-NGF be-100 no-80 nm, ngokulandelanayo (Fig. SI7). Ukujiya okuncane kwe-BS-NGF kungase kube umphumela wokungavezwa ngokuqondile kwegesi eyandulelayo.
Kudluliswe i-NGF (NiAG) ngaphandle kwe-polymer ku-SiO2/Si wafer (bona Umfanekiso 2c): (a,b) Izithombe ze-SEM ze-FS-NGF edlulisiwe: ukukhulisa okuphansi nokuphezulu (okuhambisana nesikwele esiwolintshi kuphaneli). Izindawo ezijwayelekile) - a). (c,d) Izithombe ze-SEM ze-BS-NGF edlulisiwe: ukukhuliswa okuphansi nokuphezulu (okuhambisana nendawo evamile eboniswa isikwele esiwolintshi kuphaneli c). (e, f) Izithombe ze-AFM zama-FS- kanye nama-BS-NGF adlulisiwe. Umcibisholo oluhlaza umelela isifunda se-FLG - ukugqama okukhanyayo, umcibisholo o-cyan - umehluko we-MLG omnyama, umcibisholo obomvu - umehluko omnyama umele isifunda se-NGF, umcibisholo we-magenta umele ukugoqa.
Ukwakhiwa kwamakhemikhali we-FS- kanye ne-BS-NGF ekhulile futhi edluliselwe kwahlaziywa nge-X-ray photoelectron spectroscopy (XPS) (Fig. 4). Ukuphakama okubuthakathaka kubonwe ku-spectra esilinganisiwe (Fig. 4a, b), ehambisana ne-Ni substrate (850 eV) ye-FS- kanye ne-BS-NGF ekhulile (NiAG). Azikho iziqongo ku-spectra esilinganisiwe sokudluliswa kwe-FS- ne-BS-NGF/SiO2/Si (Fig. 4c; imiphumela efanayo ye-BS-NGF/SiO2/Si ayiboniswa), ebonisa ukuthi akukho ukungcoliswa kwe-Ni okusala ngemva kokudluliselwa. . Izibalo 4d–f zibonisa i-spectra yokulungiswa okuphezulu kwe-C 1 s, O 1 s kanye namazinga wamandla we-Si 2p we-FS-NGF/SiO2/Si. Amandla okubopha we-C 1 s wegraphite ngu-284.4 eV53.54. Umumo womugqa weziqongo zegraphite ngokuvamile ubhekwa njenge-asymmetrical, njengoba kuboniswe kuMfanekiso 4d54. I-high-resolution core-level C 1 s spectrum (Fig. 4d) iphinde yaqinisekisa ukudluliswa okuhlanzekile (okungukuthi, azikho izinsalela ze-polymer), ezihambisana nezifundo zangaphambili38. Ububanzi bomugqa we-spectra ye-C 1 yesampula esanda kukhula (i-NiAG) nangemuva kokudluliselwa ngu-0.55 no-0.62 eV, ngokulandelanayo. Lawa manani aphezulu kunalawo e-SLG (0.49 eV ye-SLG ku-substrate ye-SiO2)38. Kodwa-ke, lawa manani mancane kunobubanzi bomugqa obubikiwe ngaphambilini kumasampula e-pyrolytic graphene agxile kakhulu (~0.75 eV) 53,54,55, okubonisa ukungabikho kwamasayithi ekhabhoni anesici kokubalulekile kwamanje. I-spectra yezinga eliphansi le-C 1 kanye ne-O 1 nayo ayinawo amahlombe, okuqeda isidingo se-high-resolution peak deconvolution54. Kukhona isiqongo sesathelayithi esingu-π → π* esingaba ngu-291.1 eV, esivame ukubonwa kumasampula e-graphite. Izimpawu ze-103 eV kanye ne-532.5 eV ku-Si 2p kanye ne-O 1 s core level spectra (bona i-Fig. 4e, f) kuthiwa ifakwe ku-substrate ye-SiO2 56, ngokulandelanayo. I-XPS iyindlela ezwela phezulu, ngakho-ke amasiginali ahambisana ne-Ni ne-SiO2 atholwe ngaphambi nangemuva kokudluliselwa kwe-NGF, ngokulandelanayo, kucatshangwa ukuthi asuka esifundeni se-FLG. Imiphumela efanayo yaqashelwa kumasampula e-BS-NGF adlulisiwe (angaboniswa).
Imiphumela ye-NiAG XPS: (ac) Inhlolovo ye-spectra yezakhi ezihlukile ze-athomu ezikhulile i-FS-NGF/Ni, BS-NGF/Ni futhi yadluliswa i-FS-NGF/SiO2/Si, ngokulandelanayo. (d–f) I-spectra yokulungiswa okuphezulu kwamazinga ayinhloko C 1 s, O 1s kanye no-Si 2p wesampula ye-FS-NGF/SiO2/Si.
Ikhwalithi ephelele yamakristalu e-NGF adlulisiwe yahlolwa kusetshenziswa i-X-ray diffraction (XRD). Amaphethini we-XRD ajwayelekile (Umfanekiso we-SI8) we-FS- kanye ne-BS-NGF/SiO2/Si abonisa ukuba khona kweziqongo ze-diffraction (0 0 0 2) kanye (0 0 0 4) ku-26.6 ° no-54.7 °, okufana ne-graphite. . Lokhu kuqinisekisa ikhwalithi ephezulu ye-crystalline ye-NGF futhi ihambisana nebanga le-interlayer d = 0.335 nm, eligcinwa ngemva kwesinyathelo sokudlulisa. Ukuqina kwesiqongo se-diffraction (0 0 0 2) cishe izikhathi ezingu-30 zokuphakama kwe-diffraction (0 0 0 4), okubonisa ukuthi indiza yekristalu ye-NGF ihambisana kahle nesampula.
Ngokwemiphumela ye-SEM, i-Raman spectroscopy, i-XPS kanye ne-XRD, ikhwalithi ye-BS-NGF/Ni itholwe ifana neye-FS-NGF/Ni, nakuba ubulukhuni bayo be-rms babuphakeme kancane (Izibalo SI2, SI5) kanye ne-SI7).
Ama-SLG anezendlalelo zokusekela ze-polymer afika ku-200 nm obukhulu angantanta emanzini. Lokhu kusetha kuvame ukusetshenziswa ezinqubweni zokudlulisa amakhemikhali ezimanzi ezisizwa nge-polymer22,38. Igraphene negraphite kukhona i-hydrophobic (i-engeli emanzi 80–90°) 57. Indawo yamandla engaba khona yakho kokubili i-graphene kanye ne-FLG kubikwe ukuthi isicaba impela, inamandla aphansi (~1 kJ/mol) okunyakaza kwamanzi emaceleni phezulu58. Kodwa-ke, amandla okusebenzisana okubaliwe amanzi ane-graphene kanye nezingqimba ezintathu zegraphene cishe - 13 kanye - 15 kJ / mol,58 ngokulandelana, okubonisa ukuthi ukusebenzisana kwamanzi ne-NGF (cishe izendlalelo ze-300) kuphansi uma kuqhathaniswa ne-graphene. Lokhu kungase kube esinye sezizathu zokuthi kungani i-NGF ezimele ihlale isicaba phezu kwamanzi, kuyilapho i-graphene ezimele (entanta emanzini) igoqa futhi iphuka. Uma i-NGF icwiliswe ngokuphelele emanzini (imiphumela iyafana ku-NGF emahhadlahhadla futhi eyisicaba), imiphetho yayo iyagoba (Umfanekiso SI4). Endabeni yokucwiliswa okuphelele, kulindeleke ukuthi amandla okusebenzisana kwe-NGF-amanzi acishe aphindwe kabili (uma kuqhathaniswa ne-NGF entantayo) nokuthi imiphetho ye-NGF fold ukugcina i-angle yokuxhumana ephezulu (i-hydrophobicity). Sikholelwa ukuthi amasu angathuthukiswa ukuze kugwenywe ukugoqa imiphetho yama-NGF ashumekiwe. Enye indlela ukusebenzisa izincibilikisi ezixubile ukulungisa ukusabela kokumanzisa kwefilimu ye-graphite59.
Ukudluliswa kwe-SLG ezinhlotsheni ezahlukahlukene zama-substrates ngezinqubo zokudluliswa kwamakhemikhali amanzi kuye kwabikwa ngaphambilini. Kuyamukelwa ngokuvamile ukuthi amandla abuthakathaka e-van der Waals akhona phakathi kwamafilimu e-graphene/graphite nama-substrates (kungaba ama-substrates aqinile njenge-SiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 kanye namafilimu e-lacy carbon30, 34 noma ama-substrates aguqukayo njenge-polyimide 37). Lapha sicabanga ukuthi ukusebenzisana kohlobo olufanayo kuyabusa. Asibonanga noma yimuphi umonakalo noma ukuxebuka kwe-NGF kunoma imaphi ama-substrates anikezwe lapha ngesikhathi sokuphatha ngomshini (ngesikhathi sokuhlukaniswa kwezinhlamvu ngaphansi kwe-vacuum kanye/noma izimo zomoya noma ngesikhathi sokulondoloza) (isb, Umfanekiso 2, SI7 kanye ne-SI9). Ukwengeza, asizange sibone ukuphakama kwe-SiC ku-spectrum ye-XPS C 1 yezinga eliyinhloko lesampula ye-NGF/SiO2/Si (Fig. 4). Le miphumela ibonisa ukuthi asikho isibopho samakhemikhali phakathi kwe-NGF ne-substrate ehlosiwe.
Esigabeni esandulele, "Ukudluliswa kwamahhala kwe-Polymer kwe-FS- kanye ne-BS-NGF," sibonise ukuthi i-NGF ingakhula futhi idlulisele ezinhlangothini zombili ze-nickel foil. Lawa ma-FS-NGF kanye nama-BS-NGF awafani ngokuphathelene nobulukhuni bendawo, okusishukumisele ukuba sihlole izinhlelo zokusebenza ezifanele kakhulu zohlobo ngalunye.
Uma sicabangela indawo esobala kanye nebushelelezi ye-FS-NGF, safunda isakhiwo sayo sendawo, izakhiwo zokukhanya nezikagesi ngokuningiliziwe. Isakhiwo kanye nesakhiwo se-FS-NGF ngaphandle kokudluliswa kwe-polymer kubonakala nge-imaging ye-electron microscopy (TEM) yokudlulisela kanye nokuhlaziywa kwephethini ye-electron diffraction (SAED) yendawo ekhethiwe. Imiphumela ehambisanayo ikhonjiswe kuMfanekiso 5. Isithombe se-TEM sokukhuliswa okuphansi kwembula ukuba khona kwezifunda ze-NGF ne-FLG ezinezici ezihlukile zama-electron, okungukuthi izindawo ezimnyama nezigqamile, ngokulandelana (Fig. 5a). Ifilimu iyonke ibonisa ubuqotho obuhle bemishini nokuzinza phakathi kwezifunda ezihlukene ze-NGF ne-FLG, ngokunqwabelanisa okuhle futhi akukho monakalo noma ukuklebhula, okuphinde kwaqinisekiswa yi-SEM (Umfanekiso 3) kanye nezifundo ze-TEM zokukhulisa (Figure 5c-e). Ikakhulukazi, ku-Fig. Umfanekiso we-5d ubonisa isakhiwo sebhuloho engxenyeni yayo enkulu kunazo zonke (isikhundla esimakwe umcibisholo onamachashazi amnyama ku-Figure 5d), esibonakala ngesimo sikanxantathu futhi siqukethe ungqimba lwe-graphene olunobubanzi obungaba ngu-51. Ukwakheka okunesikhala esiphakathi kwe-interplanar esingu-0.33 ± 0.01 nm kuphinde kwehliswe kube izendlalelo ezimbalwa zegraphene endaweni encane kakhulu (ekugcineni komcibisholo omnyama oqinile kuMfanekiso 5 d).
Isithombe se-Planar TEM sesampula ye-NiAG engenayo i-polymer kugridi yethusi ye-carbon lacy: (a, b) Izithombe ze-TEM ezikhuliswa kancane ezihlanganisa izifunda ze-NGF ne-FLG, (ce) Izithombe ezikhuliswa kakhulu zezifunda ezihlukahlukene kuphaneli-a kanye nephaneli-b imicibisholo ephawulwe yombala ofanayo. Imicibisholo eluhlaza kumaphaneli u-a no-c abonisa izindawo eziyindilinga zomonakalo phakathi nokuqondisa kohlaka. (f–i) Kumaphaneli ukusuka ku-a ukuya ku-c, amaphethini e-SAED ezifundeni ezihlukene aboniswa ngemibuthano eluhlaza okwesibhakabhaka, e-cyan, ewolintshi, nebomvu, ngokulandelanayo.
Isakhiwo seribhoni kuMfanekiso 5c sibonisa (okumakwe ngomcibisholo obomvu) ukuma okuqondile kwezindiza ze-graphite lattice, okungenzeka kube ngenxa yokwakheka kwama-nanofolds ahambisana nefilimu (okufakwe kumfanekiso 5c) ngenxa yokucindezeleka kwe-shear okunganxeshezelwa30,61,62 . Ngaphansi kwe-TEM yokulungiswa okuphezulu, lawa ma-nanofolds angu-30 abonisa i-crystallographic orientation ehlukile kuneso sonke isifunda se-NGF; izindiza eziyisisekelo ze-graphite lattice ziqondiswe cishe ziqondile, kunokuba zivundlile njengefilimu yonke (okufakwe kumfanekiso 5c). Ngokufanayo, isifunda se-FLG ngezikhathi ezithile sibonisa ukugoqa okufana nebhande eliwumugqa neliwumngcingo (emakwe ngemicibisholo eluhlaza okwesibhakabhaka), avela ngokukhuliswa okuphansi nokuphakathi ku-Figure 5b, 5e, ngokulandelana. I-inset ku-Figure 5e iqinisekisa ukuba khona kwezingqimba ze-graphene ezimbili nezintathu emkhakheni we-FLG (ibanga le-interplanar 0.33 ± 0.01 nm), okuvumelana kahle nemiphumela yethu yangaphambili30. Ukwengeza, izithombe ze-SEM ezirekhodiwe ze-NGF engena-polymer edluliselwe kumagridi ethusi anamafilimu ekhabhoni lacy (ngemuva kokwenza izilinganiso ze-TEM zokubuka okuphezulu) ziboniswa kuMfanekiso SI9. Isifunda se-FLG esimiswe kahle (emakwe ngomcibisholo oluhlaza okwesibhakabhaka) kanye nesifunda esiphukile kuMfanekiso SI9f. Umcibisholo oluhlaza okwesibhakabhaka (emaphethelweni e-NGF edlulisiwe) wethulwa ngenhloso ukuze ubonise ukuthi isifunda se-FLG singamelana nenqubo yokudlulisa ngaphandle kwe-polymer. Kafushane, lezi zithombe ziqinisekisa ukuthi i-NGF emiswe kancane (okuhlanganisa nesifunda se-FLG) igcina ubuqotho bokusebenza ngisho nangemva kokuphatha kanzima kanye nokuchayeka ku-vacuum ephezulu phakathi nezilinganiso ze-TEM ne-SEM (Umfanekiso SI9).
Ngenxa yokunethezeka okuhle kakhulu kwe-NGF (bona Umfanekiso 5a), akunzima ukuqondisa ama-flakes eduze kwe-axis yesizinda se- [0001] ukuhlaziya isakhiwo se-SAED. Kuye ngobukhulu bendawo befilimu kanye nendawo yayo, izifunda eziningana ezithakazelisayo (amaphuzu angu-12) zihlonzwe ngezifundo ze-electron diffraction. Emfanekisweni 5a–c, ezine zalezi zifunda ezijwayelekile ziyakhonjiswa futhi zimakwe ngezindingilizi ezinombala (oluhlaza okwesibhakabhaka, oluhlaza okwesibhakabhaka, oluhlaza okwesibhakabhaka, olusawolintshi, olunamakhodi abomvu). Izibalo 2 no-3 zemodi ye-SAED. Amanani angu-5f no-g atholwe esifundeni se-FLG esiboniswe ku-Figure 5 no-5. Njengoba kuboniswe ku-Figure 5b no-c, ngokulandelanayo. Zinesakhiwo esiyi-hexagonal esifana ne-graphene63 esontekile. Ikakhulukazi, Umfanekiso 5f ubonisa amaphethini amathathu abekwe phezulu anomumo ofanayo we-eksisi yezoni ye-[0001], ezungeziswa ngo-10° no-20°, njengoba kufakazelwa ukungafani kwe-angular kwamapheya amathathu okubonisa (10-10). Ngokufanayo, Umfanekiso 5g ubonisa amaphethini amabili ane-hexagonal abekwe phezulu azungeziswe ngo-20°. Amaqembu amabili noma amathathu amaphethini ane-hexagonal esifundeni se-FLG angavela kuzingqimba ezintathu ze-graphene ezingaphakathi noma ezingaphandle kwendiza ezingu-33 ezizungeziswe ngokuhlobene. Ngokuphambene, amaphethini e-electron diffraction ku-Figure 5h, i (okuhambisana nesifunda se-NGF esiboniswe kuMfanekiso 5a) abonisa iphethini eyodwa ye- [0001] enephuzu eliphezulu lokuhluka kwephuzu elinamandla, elihambisana nokujiya okukhulu kwempahla. Lawa mamodeli e-SAED ahambisana nesakhiwo se-graphite esijiyile kanye nokuma okuphakathi nendawo kune-FLG, njengoba kuqondiswe kunkomba engu-64. Ukuchazwa kwezimpawu ze-crystalline ze-NGF zembule ukuhlangana kwamakristalu amabili noma amathathu e-graphite (noma i-graphene). Okuphawuleka kakhulu esifundeni se-FLG ukuthi amakristalu anezinga elithile lokungahloniphi okungaphakathi kwendiza noma okungaphandle kwendiza. Izinhlayiya ze-graphite/izendlalelo ezinama-engeli wokuzungezisa endizeni angu-17°, 22° kanye no-25° ngaphambilini kuye kwabikwa ku-NGF etshalwe kumafilimu e-Ni 64. Amanani e-engeli yokuzungezisa aqashelwe kulolu cwaningo ahambisana nama-engeli azungezayo abonwe ngaphambilini (±1°) we-graphene ye-BLG63 esontekile.
Izakhiwo zikagesi ze-NGF/SiO2/Si zikalwe ku-300 K endaweni engu-10×3 mm2. Amanani we-electron carrier concentration, ukuhamba kanye ne-conductivity yi-1.6 × 1020 cm-3, 220 cm2 V-1 C-1 kanye ne-2000 S-cm-1, ngokulandelana. Amanani okuhamba kanye ne-conductivity ye-NGF yethu afana ne-graphite2 yemvelo futhi ephakeme kune-graphite ye-pyrolytic etholakala kakhulu kwezohwebo (ekhiqizwe ku-3000 ° C)29. Amanani okugxiliswa kwe-electron carrier carrier ama-oda amabili aphezulu kunalawo asanda kubikwa (7.25 × 10 cm-3) kumafilimu e-graphite aminyene amancane alungiselelwe kusetshenziswa izinga lokushisa eliphezulu (3200 °C) amashidi e-polyimide angu-20.
Siphinde senza izilinganiso zokudlulisa ezibonakalayo ze-UV ku-FS-NGF ezidluliselwe kuma-quartz substrates (Umfanekiso 6). I-spectrum ewumphumela ibonisa ukudluliswa okuqhubekayo okungama-62% kububanzi obungu-350–800 nm, okubonisa ukuthi i-NGF ishintshashintsha ekukhanyeni okubonakalayo. Eqinisweni, igama elithi "KAUST" lingabonakala esithombeni sedijithali sesampula kuMfanekiso 6b. Nakuba isakhiwo se-nanocrystalline se-NGF sihlukile kune-SLG, inani lezendlalelo lingalinganiselwa cishe lisebenzisa umthetho wokulahlekelwa kokudluliswa kwe-2.3% ngesendlalelo esengeziwe65. Ngokwalobu budlelwano, inani lezendlalelo ze-graphene ezinokulahlekelwa kokudluliswa kuka-38% yi-21. I-NGF ekhulile ngokuyinhloko iqukethe izendlalelo ze-graphene ezingu-300, okungukuthi cishe u-100 nm obukhulu (Fig. 1, SI5 kanye ne-SI7). Ngakho-ke, sicabanga ukuthi ukubonakala kwe-optical okuphawuliwe kuhambisana nezifunda ze-FLG ne-MLG, njengoba zisatshalaliswa kuyo yonke ifilimu (Amakhiwane 1, 3, 5 kanye no-6c). Ngokungeziwe kudatha yesakhiwo engenhla, ukuqhutshwa nokubeka izinto obala nakho kuqinisekisa ikhwalithi ephezulu yekristalu ye-NGF edlulisiwe.
(a) Ukulinganisa kokudluliswa okubonakalayo kwe-UV, (b) ukudluliswa okujwayelekile kwe-NGF ku-quartz kusetshenziswa isampula elimele. (c) Isikimu se-NGF (ibhokisi elimnyama) elinezifunda ezisatshalaliswe ngokulinganayo ze-FLG ne-MLG ezimakwe njengezimo ezingahleliwe ezimpunga kuyo yonke isampula (bona Umfanekiso 1) (cishe indawo engu-0.1–3% ngo-100 μm2). Izimo ezingahleliwe nosayizi bazo kumdwebo ezezinjongo zemifanekiso kuphela futhi azihambisani nezindawo zangempela.
I-Translucent NGF ekhuliswe yi-CVD ngaphambilini idluliselwe ezindaweni ezingenalutho ze-silicon futhi yasetshenziswa kumaseli elanga15,16. Ukusebenza kahle kokuguqulwa kwamandla okuphumela (PCE) yi-1.5%. Lawa ma-NGF enza imisebenzi eminingi njengezendlalelo ezihlanganisiwe ezisebenzayo, izindlela zokuhamba zokushaja, kanye nama-electrode asobala15,16. Nokho, ifilimu ye-graphite ayifani. Ukuthuthukiswa okwengeziwe kuyadingeka ngokulawula ngokucophelela ukumelana kweshidi kanye nokudluliswa kwe-optical ye-graphite electrode, njengoba lezi zakhiwo ezimbili zidlala indima ebalulekile ekunqumeni inani le-PCE le-solar cell15,16. Ngokuvamile, amafilimu e-graphene anokukhanya okungama-97.7% ekukhanyeni okubonakalayo, kodwa anokumelana kweshidi okungu-200-3000 ohms/sq.16. Ukumelana okungaphezulu kwamafilimu e-graphene kungancishiswa ngokwandisa inani lezendlalelo (ukudluliselwa okuningi kwezingqimba ze-graphene) kanye ne-doping nge-HNO3 (~30 Ohm/sq.)66. Kodwa-ke, le nqubo ithatha isikhathi eside futhi izendlalelo ezihlukene zokudlulisa azigcini ukuxhumana okuhle ngaso sonke isikhathi. Uhlangothi lwethu lwangaphambili lwe-NGF lunezakhiwo ezifana ne-conductivity 2000 S/cm, ukumelana neshidi lefilimu 50 ohm/sq. kanye nokungafihli okungu-62%, okwenza kube enye indlela esebenzayo yamashaneli e-conductive noma ama-electrode ekhawunta kumaseli elanga15,16.
Nakuba ukwakheka kanye namakhemikhali angaphezulu kwe-BS-NGF kufana ne-FS-NGF, ukuhlubuka kwayo kuhlukile (“Ukukhula kwe-FS- kanye ne-BS-NGF”). Ngaphambilini, sasisebenzisa ifilimu ye-ultra-thin graphite22 njengenzwa yegesi. Ngakho-ke, sihlole ukuthi kungenzeka yini ukusebenzisa i-BS-NGF emisebenzini yokuzwa igesi (Umfanekiso SI10). Okokuqala, izingxenye ezinosayizi we-mm2 ze-BS-NGF zadluliselwa ku-chip yenzwa ye-electrode interdigitating (Figure SI10a-c). Imininingwane yokukhiqiza ye-chip ibikwe ngaphambilini; indawo yayo ebucayi esebenzayo ingu-9 mm267. Ezithombeni ze-SEM (Umdwebo SI10b no-c), i-electrode yegolide engaphansi ibonakala ngokucacile nge-NGF. Futhi, kungabonakala ukuthi ukumbozwa kwe-chip efanayo kwafinyelelwa kuwo wonke amasampula. Izilinganiso zezinzwa zegesi zamagesi ahlukahlukene zarekhodwa (Fig. SI10d) (Fig. SI11) kanye namazinga okuphendula avelayo aboniswa ku-Fig. SI10g. Cishe namanye amagesi aphazamisayo ahlanganisa i-SO2 (200 ppm), i-H2 (2%), i-CH4 (200 ppm), i-CO2 (2%), i-H2S (200 ppm) ne-NH3 (200 ppm). Isizathu esisodwa esingaba ngu-NO2. imvelo ye-electrophilic yegesi22,68. Uma ikhangisiwe ebusweni be-graphene, yehlisa ukumuncwa kwama-electron kwamanje yisistimu. Ukuqhathaniswa kwedatha yesikhathi sokuphendula yenzwa ye-BS-NGF enezinzwa ezishicilelwe ngaphambilini kuvezwa kuThebula SI2. Umshini wokuvuselela izinzwa ze-NGF usebenzisa i-UV plasma, i-O3 plasma noma ukwelashwa okushisayo (50-150 ° C) kwamasampuli avuliwe kuyaqhubeka, okulandelwa kahle ukuqaliswa kwezinhlelo ezishunyekiwe69.
Phakathi nenqubo ye-CVD, ukukhula kwe-graphene kwenzeka ezinhlangothini zombili ze-catalyst substrate41. Nokho, i-BS-graphene ivamise ukukhishwa phakathi nenqubo yokudlulisa41. Kulolu cwaningo, sibonisa ukuthi ukukhula kwekhwalithi ephezulu ye-NGF nokudluliswa kwe-NGF kwe-polymer-free kungafinyelelwa ezinhlangothini zombili zokusekelwa kwe-catalyst. I-BS-NGF izacile (~80 nm) kune-FS-NGF (~100 nm), futhi lo mehluko uchazwa ukuthi i-BS-Ni ayivezwa ngokuqondile ekugelezeni kwegesi eyandulelayo. Siphinde sathola ukuthi ukuhwalala kwe-substrate ye-NiAR kunomthelela ekuqineni kwe-NGF. Le miphumela ibonisa ukuthi i-planar ekhulile i-FS-NGF ingasetshenziswa njenge-precursor material ye-graphene (nge-exfoliation method70) noma njengendlela yokuhambisa kumaseli elanga15,16. Ngokuphambene, i-BS-NGF izosetshenziselwa ukutholwa kwegesi (Fig. SI9) futhi ngokunokwenzeka nasezinhlelweni zokugcina amandla71,72 lapho ubulukhuni bayo obungaphezulu buyoba usizo.
Uma ucabangela lokhu okungenhla, kuyasiza ukuhlanganisa umsebenzi wamanje namafilimu e-graphite ashicilelwe ngaphambilini atshalwa yi-CVD nokusebenzisa i-nickel foil. Njengoba kungabonwa kuThebula 2, izingcindezi eziphakeme esizisebenzisile zifinyeza isikhathi sokusabela (isigaba sokukhula) ngisho nasezingeni eliphansi lokushisa uma kuqhathaniswa (kububanzi obungu-850–1300 °C). Siphinde sazuza ukukhula okukhulu kunokuvamile, okubonisa amathuba okwanda. Kunezinye izici okufanele zibhekwe, ezinye zazo esizifakile etafuleni.
I-NGF yekhwalithi ephezulu enezinhlangothi ezimbili ikhuliswe ku-nickel foil nge-catalytic CVD. Ngokususa ama-polymer substrates endabuko (njengalawo asetshenziswa ku-CVD graphene), sifinyelela ukudluliswa okumanzi okuhlanzekile nokungenasici kwe-NGF (ekhuliswe ngemuva nangaphambili emaceleni e-nickel foil) kuya ku-substrates ebaluleke kakhulu inqubo. Ngokuphawulekayo, i-NGF ihlanganisa izifunda ze-FLG ne-MLG (imvamisa u-0.1% ukuya ku-3% nge-100 µm2 ngayinye) ezihlanganiswe kahle nefilimu ewugqinsi. I-Planar TEM ibonisa ukuthi lezi zifunda zakhiwe izitaki ezimbili kuya kwezintathu zezinhlayiya zegraphite/graphene (amakristalu noma izendlalelo, ngokulandelana), ezinye zazo ezinokungafani kokujikeleza okungu-10–20°. Izifunda ze-FLG ne-MLG zinesibopho sokubonisa ngale kwe-FS-NGF ekukhanyeni okubonakalayo. Ngokuqondene namashidi angemuva, angathwalwa ngokuhambisana namashidi angaphambili futhi, njengoba kubonisiwe, angaba nenjongo yokusebenza (isibonelo, ukutholwa kwegesi). Lezi zifundo ziwusizo kakhulu ekwehliseni imfucuza kanye nezindleko kuzinqubo ze-CVD zezimboni.
Ngokuvamile, ukushuba okumaphakathi kwe-CVD NGF kuphakathi kwamashidi egraphene (ama-low- and multi-layer) nama-industrial (micrometer). Ububanzi bezindawo zabo ezithakazelisayo, kuhlangene nendlela elula esiyithuthukisile ukukhiqizwa nokuthutha kwabo, kwenza lawa mafilimu afaneleke ngokukhethekile izinhlelo zokusebenza ezidinga impendulo yokusebenza ye-graphite, ngaphandle kwezindleko zezinqubo zokukhiqiza ezimbonini ezisetshenziswa ngamandla manje.
Iphepha le-nickel elingu-25-μm-thick (99.5% purity, Goodfellow) lifakwe kureactor ye-CVD yezentengiso (Aixtron 4-inch BMPro). Isistimu yahlanzwa nge-argon futhi yahanjiswa ekucindezelweni okuyisisekelo kwe-10-3 mbar. Khona-ke i-nickel foil yafakwa. ku-Ar/H2 (Ngemva kokufakwa ngaphambilini kwe-Ni foil ye-5 min, i-foil yavezwa ekucindezelweni kwe-500 mbar ku-900 ° C. I-NGF ifakwe ekugelezeni kwe-CH4 / H2 (100 cm3 ngayinye) imizuzu engu-5. Isampula libe selipholiswa kuzinga lokushisa elingaphansi kuka-700 °C kusetshenziswa ukugeleza kwe-Ar (4000 cm3) ku-40 °C/min Imininingwane yokwenziwa kahle kwenqubo yokukhula ye-NGF ichazwe kwenye indawo30.
I-morphology engaphezulu yesampula yabonwa yi-SEM isebenzisa isibonakhulu se-Zeiss Merlin (1 kV, 50 pA). Isampula yobulukhuni bendawo nobukhulu be-NGF kukalwe kusetshenziswa i-AFM (Dimension Icon SPM, Bruker). Izilinganiso ze-TEM ne-SAED zenziwa kusetshenziswa isibonakhulu se-FEI Titan 80–300 Cubed esifakwe isibhamu esikhipha ukukhanya okuphakeme (300 kV), i-FEI Wien yohlobo lwe-monochromator kanye ne-CEOS lens ye-spherical aberration corrector ukuze kutholwe imiphumela yokugcina. ukulungiswa kwendawo 0.09 nm. Amasampula e-NGF adluliselwe kumagridi ethusi ane-carbon lacy enziwe nge-flat TEM imaging kanye nokuhlaziywa kwesakhiwo se-SAED. Ngakho-ke, ama-flocs amaningi esampula amisiwe ezimbotsheni zolwelwesi olusekelayo. Amasampula e-NGF adlulisiwe ahlaziywa yi-XRD. Amaphethini e-X-ray diffraction atholwe kusetshenziswa i-powder diffractometer (i-Brucker, i-D2 phase shifter enomthombo we-Cu Kα, 1.5418 Å kanye nomtshina we-LYNXEYE) kusetshenziswa umthombo wemisebe u-Cu onobubanzi bendawo ye-beam obungu-3 mm.
Izilinganiso ezimbalwa zamaphoyinti e-Raman zarekhodwa kusetshenziswa isibonakhulu esihlanganisayo esihlanganisayo (Alpha 300 RA, WITeC). Ilaser engu-532 nm enamandla aphansi avusa amadlingozi (25%) yasetshenziswa ukugwema imiphumela ebangelwa ukushisa. I-X-ray photoelectron spectroscopy (XPS) yenziwa ku-Kratos Axis Ultra spectrometer endaweni eyisampula engu-300 × 700 μm2 kusetshenziswa imisebe ye-Al Kα e-monochromatic (hν = 1486.6 eV) ngamandla angu-150 W. Ukubuka kwe-Resolution kutholwe amandla okudlulisa angu-160 eV kanye no-20 eV, ngokulandelana. Amasampula e-NGF adluliselwe ku-SiO2 asikwa abe yizicucu (3 × 10 mm2 ngayinye) kusetshenziswa i-PLS6MW (1.06 μm) i-ytterbium fiber laser ku-30 W. Oxhumana nabo bezintambo ze-Copper (ubukhulu obungama-50 μm) benziwe kusetshenziswa ukunamathisela kwesiliva ngaphansi kwesibonakhulu esibonakalayo. Ukuhlolwa kwezokuthutha ngogesi kanye nomphumela waseHholo kwenziwa kulawa masampuli ku-300 K kanye nokuhlukahluka kwenkundla kazibuthe engu-± 9 Tesla ohlelweni lokulinganisa izakhiwo ezibonakalayo (PPMS EverCool-II, Quantum Design, USA). Ukubukwa kwe-UV–vis okudlulisiwe kwarekhodwa kusetshenziswa i-Lambda 950 UV–vis spectrophotometer ebangeni elingu-350–800 nm NGF elidluliselwe kuma-substrates e-quartz namasampula ereferensi e-quartz.
Inzwa yokumelana namakhemikhali (i-interdigitated electrode chip) yayixhunywe ebhodini lesifunda eliphrintiwe ngokwezifiso elingu-73 futhi ukumelana kwakhishwa okwesikhashana. Ibhodi lesifunda eliphrintiwe lapho idivayisi itholakala khona ixhunywe kumatheminali okuxhumana futhi ifakwe ngaphakathi kwegumbi lokuzwa igesi 74. Izilinganiso zokumelana zithathwe ku-voltage engu-1 V ngokuskena okuqhubekayo kusukela ekuhlanzeni kuya ekuchayekeni kwegesi bese kuhlanzwa futhi. Igumbi laqale lahlanzwa ngokuhlanzwa nge-nitrogen ku-200 cm3 ngehora elingu-1 ukuze kuqinisekiswe ukususwa kwazo zonke ezinye izihlaziyi ezikhona ekamelweni, kuhlanganise nomswakama. Abahlaziyi ngabanye babe sebededelwa kancane kancane ekamelweni ngezinga lokugeleza elifanayo lika-200 cm3 ngokuvala isilinda i-N2.
Inguqulo ebuyekeziwe yalesi sihloko ishicilelwe futhi ingafinyelelwa ngesixhumanisi esingaphezulu kwesihloko.
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Isikhathi sokuthumela: Aug-23-2024