Siyabonga ngokuvakashela i-Nature.com. Inguqulo yesiphequluli osisebenzisayo inokusekelwa okulinganiselwe kwe-CSS. Ukuze uthole imiphumela emihle kakhulu, sincoma ukuthi usebenzise inguqulo entsha yesiphequluli sakho (noma ukhubaze i-Compatibility Mode ku-Internet Explorer). Okwamanje, ukuqinisekisa ukwesekwa okuqhubekayo, sibonisa isayithi ngaphandle kwesitayela noma i-JavaScript.
Amafilimu e-Nanoscale graphite (ama-NGF) ayizinto eziqinile ze-nanomaterial ezingakhiqizwa yi-catalytic chemical vapor deposition, kodwa kusasele imibuzo mayelana nokulula kokudluliselwa kwazo nokuthi i-surface morphology ithinta kanjani ukusetshenziswa kwazo kumadivayisi esizukulwane esilandelayo. Lapha sibika ukukhula kwe-NGF kuzo zombili izinhlangothi ze-polycrystalline nickel foil (indawo engu-55 cm2, ukujiya okungaba ngu-100 nm) kanye nokudluliselwa kwayo okungena-polymer (ngaphambili nangemuva, indawo efika ku-6 cm2). Ngenxa ye-morphology ye-catalyst foil, amafilimu amabili e-carbon ahlukile ngezakhiwo zawo zomzimba kanye nezinye izici (njengokulukhuni kobuso). Sibonisa ukuthi ama-NGF ane-backside eqinile afaneleka kahle ekutholakaleni kwe-NO2, kuyilapho ama-NGF abushelelezi futhi aqhuba kakhulu ohlangothini olungaphambili (2000 S/cm, ukumelana kweshidi - 50 ohms/m2) angaba abaqhubi abasebenzayo. isiteshi noma i-electrode yeseli yelanga (njengoba idlulisela u-62% wokukhanya okubonakalayo). Sekukonke, izinqubo zokukhula nezokuthutha ezichazwe zingasiza ekufezeni i-NGF njengenye indlela yokwenza ikhabhoni yezinhlelo zokusebenza zobuchwepheshe lapho amafilimu e-graphene kanye ne-micron-thick graphite engafaneleki.
I-Graphite iyinto esetshenziswa kakhulu ezimbonini. Okuphawulekayo ukuthi i-graphite inezakhiwo zobuningi obuphansi kanye nokushisa okuphezulu kanye nokuqhuba okuphezulu kokushisa kanye nogesi, futhi izinzile kakhulu ezindaweni ezishisayo nezimakhemikhali ezinzima1,2. I-Flake graphite iyinto yokuqala eyaziwayo yocwaningo lwe-graphene3. Uma icutshungulwa ibe amafilimu amancane, ingasetshenziswa ezinhlobonhlobo zezicelo, kufaka phakathi ama-heat sink amadivayisi kagesi afana nama-smartphone4,5,6,7, njengento esebenzayo kuma-sensors8,9,10 kanye nokuvikela ukuphazamiseka kwe-electromagnetic11.12 namafilimu e-lithography ku-ultraviolet extreme13,14, eqhuba iziteshi kumaseli elanga15,16. Kuzo zonke lezi zicelo, kungaba yinzuzo enkulu uma izindawo ezinkulu zamafilimu e-graphite (NGFs) anobukhulu obulawulwa ku-nanoscale <100 nm zingakhiqizwa futhi zithuthwe kalula.
Amafilimu e-graphite akhiqizwa ngezindlela ezahlukene. Kwesinye isimo, ukushumeka nokwandiswa okulandelwa ukukhushulwa kwasetshenziswa ukukhiqiza ama-graphene flakes10,11,17. Ama-flakes kumele aqhutshwe abe amafilimu anobukhulu obudingekayo, futhi kuvame ukuthatha izinsuku eziningana ukukhiqiza amaphepha e-graphite aminyene. Enye indlela ukuqala ngama-graphite solid precursors. Embonini, amaphepha e-polymers ayashiswa nge-carbon (ku-1000–1500 °C) bese eshiswa nge-graphit (ku-2800–3200 °C) ukuze kwakhiwe izinto ezakhiwe kahle. Nakuba ikhwalithi yala mafilimu iphezulu, ukusetshenziswa kwamandla kubalulekile1,18,19 futhi ubukhulu obuncane bunqunyelwe kuma-microns ambalwa1,18,19,20.
I-Catalytic chemical vapor deposition (CVD) iyindlela eyaziwayo yokukhiqiza amafilimu e-graphene kanye ne-ultrathin graphite (<10 nm) anekhwalithi ephezulu yesakhiwo kanye nezindleko ezinengqondo21,22,23,24,25,26,27. Kodwa-ke, uma kuqhathaniswa nokukhula kwamafilimu e-graphene kanye ne-ultrathin graphite28, ukukhula kwendawo enkulu kanye/noma ukusetshenziswa kwe-NGF kusetshenziswa i-CVD akuhlolisiswa kakhulu11,13,29,30,31,32,33.
Amafilimu e-graphene ne-graphite akhuliswe nge-CVD avame ukudinga ukudluliselwa kuma-substrate asebenzayo34. Lokhu kudluliselwa kwamafilimu amancane kuhilela izindlela ezimbili eziyinhloko35: (1) ukudluliselwa okungashisi i-etch36,37 kanye (2) ukudluliselwa kwamakhemikhali amanzi asekelwe ku-etch (i-substrate esekelwayo)14,34,38. Indlela ngayinye inezinzuzo kanye nokungalungi okuthile futhi kumele ikhethwe kuye ngokusetshenziswa okuhlosiwe, njengoba kuchaziwe kwenye indawo35,39. Kumafilimu e-graphene/graphite akhuliswe kuma-substrate e-catalytic, ukudluliselwa ngezinqubo zamakhemikhali ezimanzi (lapho i-polymethyl methacrylate (PMMA) iwungqimba lokusekela olusetshenziswa kakhulu) kuhlala kuyisinqumo sokuqala13,30,34,38,40,41,42. Wena nabanye. Kukhulunywe ukuthi akukho polymer eyasetshenziswa ukudluliselwa kwe-NGF (usayizi wesampula cishe u-4 cm2)25,43, kodwa akukho mininingwane enikeziwe mayelana nokuzinza kwesampula kanye/noma ukuphathwa ngesikhathi sokudluliselwa; Izinqubo ze-chemistry ezimanzi ezisebenzisa ama-polymers ziqukethe izinyathelo eziningana, okuhlanganisa ukusetshenziswa kanye nokususwa okulandelayo kwesendlalelo se-polymer esihlatshwayo30,38,40,41,42. Le nqubo inezinkinga: isibonelo, izinsalela ze-polymer zingashintsha izakhiwo zefilimu ekhulile38. Ukucubungula okwengeziwe kungasusa i-polymer esele, kodwa lezi zinyathelo ezengeziwe zandisa izindleko nesikhathi sokukhiqizwa kwefilimu38,40. Ngesikhathi sokukhula kwe-CVD, ungqimba lwe-graphene lufakwa hhayi kuphela ohlangothini lwangaphambili lwe-catalyst foil (uhlangothi olubhekene nokugeleza komusi), kodwa futhi nangemuva kwalo. Kodwa-ke, lokhu kokugcina kubhekwa njengomkhiqizo olahliwe futhi kungasuswa ngokushesha yi-plasma ethambile38,41. Ukuphinda usebenzise le filimu kungasiza ekukhuliseni isivuno, noma ngabe isezingeni eliphansi kunefilimu ye-carbon.
Lapha, sibika ukulungiswa kokukhula kwe-NGF okune-wafer-scale bifacial ngekhwalithi ephezulu yesakhiwo ku-polycrystalline nickel foil yi-CVD. Kuhlolwe ukuthi ubulukhuni bobuso bangaphambili nangemuva be-foil buthinta kanjani isimo kanye nesakhiwo se-NGF. Siphinde sibonise ukudluliselwa kwe-NGF okungenazindleko futhi okungenawo ama-polymer emvelo kusuka ezinhlangothini zombili ze-nickel foil kuya ezindaweni eziningi ezisebenzayo futhi sibonise ukuthi amafilimu angaphambili nangemuva afaneleka kanjani ezinhlelweni ezahlukahlukene.
Izigaba ezilandelayo zixoxa ngobukhulu obuhlukene befilimu ye-graphite kuye ngenani lezingqimba ze-graphene ezihlanganisiwe: (i) i-graphene yengqimba eyodwa (SLG, ungqimba olu-1), (ii) i-graphene yengqimba ezimbalwa (FLG, < izingqimba eziyi-10), (iii) i-graphene yengqimba eziningi (MLG, izingqimba eziyi-10-30) kanye (iv) ne-NGF (~ izingqimba ezingama-300). Lokhu kokugcina ubukhulu obuvame kakhulu obuvezwa njengephesenti lendawo (cishe indawo engu-97% ku-100 µm2)30. Yingakho ifilimu yonke ibizwa nje ngokuthi i-NGF.
Ama-polycrystalline nickel foil asetshenziselwa ukwenziwa kwamafilimu e-graphene ne-graphite anezimo ezahlukene ngenxa yokukhiqizwa kwawo kanye nokucutshungulwa okulandelayo. Muva nje sibike ucwaningo lokuthuthukisa inqubo yokukhula kwe-NGF30. Sibonisa ukuthi amapharamitha enqubo afana nesikhathi sokufaka kanye nokucindezela kwegumbi ngesikhathi sokukhula adlala indima ebalulekile ekutholeni ama-NGF anobukhulu obufanayo. Lapha, siqhubekile nokuhlola ukukhula kwe-NGF ebusweni obucwebezelayo (FS) kanye nobuso obungacwebezeli emuva (BS) be-nickel foil (Isithombe 1a). Izinhlobo ezintathu zamasampula i-FS ne-BS zihlolwe, ezibalwe kuThebula 1. Lapho kuhlolwa ngokubonakalayo, ukukhula okufanayo kwe-NGF kuzo zombili izinhlangothi ze-nickel foil (NiAG) kungabonakala ngokushintsha kombala we-bulk Ni substrate kusuka ku-silver grey yensimbi ephawulekayo kuya kumbala ompunga o-matte (Isithombe 1a); izilinganiso ezincane ziqinisekisiwe (Isithombe 1b, c). I-Raman spectrum ejwayelekile ye-FS-NGF ebonwe esifundeni esikhanyayo futhi iboniswe ngemicibisholo ebomvu, eluhlaza okwesibhakabhaka kanye ne-orange ku-Isithombe 1b iboniswe ku-Isithombe 1c. Iziqongo zeRaman eziphawulekayo ze-graphite G (1683 cm−1) kanye ne-2D (2696 cm−1) ziqinisekisa ukukhula kwe-NGF ecwebezelayo kakhulu (Isithombe 1c, Ithebula SI1). Kuyo yonke ifilimu, kwabonakala ubukhulu be-Raman spectra enesilinganiso sokuqina (I2D/IG) ~0.3, kuyilapho i-Raman spectra ene-I2D/IG = 0.8 yayingabonwa njalo. Ukungabikho kweziqongo ezinephutha (D = 1350 cm-1) kuyo yonke ifilimu kubonisa ikhwalithi ephezulu yokukhula kwe-NGF. Imiphumela efanayo yeRaman yatholakala kusampula ye-BS-NGF (Isithombe SI1 a kanye no-b, Ithebula SI1).
Ukuqhathaniswa kwe-NiAG FS- kanye ne-BS-NGF: (a) Isithombe sesampula ejwayelekile ye-NGF (NiAG) ekhombisa ukukhula kwe-NGF esikalini se-wafer (55 cm2) kanye namasampula e-foil e-BS- kanye ne-FS-Ni aphumayo, (b) Izithombe ze-FS-NGF/Ni ezitholwe nge-microscope ebonakalayo, (c) ama-spectra ajwayelekile e-Raman aqoshwe ezindaweni ezahlukene kuphaneli b, (d, f) Izithombe ze-SEM ekukhulisweni okuhlukile ku-FS-NGF/Ni, (e, g) Izithombe ze-SEM ekukhulisweni okuhlukile Amasethi e-BS -NGF/Ni. Umcibisholo oluhlaza okwesibhakabhaka ukhombisa isifunda se-FLG, umcibisholo o-orenji ukhombisa isifunda se-MLG (eduze nesifunda se-FLG), umcibisholo obomvu ubonisa isifunda se-NGF, kanye nomcibisholo o-magenta ukhombisa ukugoqa.
Njengoba ukukhula kuncike ekujiyeni kwesisekelo sokuqala, usayizi wekristalu, ukuqondiswa, kanye nemingcele yezinhlamvu, ukufeza ukulawula okunengqondo kobukhulu be-NGF ezindaweni ezinkulu kusalokhu kuyinselele20,34,44. Lolu cwaningo lusebenzise okuqukethwe esikushicilele ngaphambilini30. Le nqubo ikhiqiza indawo ekhanyayo engu-0.1 kuya ku-3% nge-100 µm230. Ezigabeni ezilandelayo, sethula imiphumela yazo zombili izinhlobo zezifunda. Izithombe ze-SEM zokukhulisa okuphezulu zibonisa ukuba khona kwezindawo eziningana ezikhanyayo ezihlukile ezinhlangothini zombili (Umfanekiso 1f, g), okubonisa ukuba khona kwezifunda ze-FLG kanye ne-MLG30,45. Lokhu kwaqinisekiswa futhi yi-Raman scattering (Umfanekiso 1c) kanye nemiphumela ye-TEM (okuxoxwe ngayo kamuva esigabeni esithi “FS-NGF: isakhiwo kanye nezakhiwo”). Izifunda ze-FLG kanye ne-MLG ezibonwe kumasampula e-FS- kanye ne-BS-NGF/Ni (i-NGF yangaphambili nangemuva ekhule ku-Ni) kungenzeka ukuthi zikhule ezinhlamvini ezinkulu ze-Ni(111) ezakhiwe ngesikhathi sokufakwa kwe-pre-annealing22,30,45. Ukugoqana kwabonakala kuzo zombili izinhlangothi (Isithombe 1b, simakwe ngemicibisholo ensomi). Lawa magoqana avame ukutholakala kumafilimu e-graphene ne-graphite akhuliswe nge-CVD ngenxa yomehluko omkhulu ku-coefficient of thermal expansion phakathi kwe-graphite kanye ne-nickel substrate30,38.
Isithombe se-AFM siqinisekisile ukuthi isampula ye-FS-NGF yayithambile kunesampula ye-BS-NGF (Isithombe SI1) (Isithombe SI2). Amanani obulukhuni be-root mean square (RMS) be-FS-NGF/Ni (Isithombe SI2c) kanye ne-BS-NGF/Ni (Isithombe SI2d) angama-82 kanye nama-200 nm, ngokulandelana (alinganiswa endaweni engama-20 × 20 μm2). Ubulukhuni obuphezulu bungaqondwa ngokusekelwe ekuhlaziyweni kobuso be-foil ye-nickel (NiAR) esimweni esamukelwe (Isithombe SI3). Izithombe ze-SEM ze-FS kanye ne-BS-NiAR ziboniswe ku-Figures SI3a–d, zibonisa izimo ezahlukene zobuso: i-foil ye-FS-Ni epholishiwe inezinhlayiya eziyindilinga ezinobukhulu be-nano- kanye ne-micron, kuyilapho i-foil ye-BS-Ni engapholishiwe ibonisa ileli lokukhiqiza. njengezinhlayiya ezinamandla aphezulu. kanye nokwehla. Izithombe eziphansi neziphezulu ze-foil ye-nickel epholishiwe (NiA) ziboniswe ku-Figure SI3e–h. Kulezi zibalo, singabona ukuba khona kwezinhlayiya eziningana ze-nickel ezinobukhulu be-micron kuzo zombili izinhlangothi ze-nickel foil (Isithombe SI3e–h). Okusanhlamvu okukhulu kungaba nokuma kobuso be-Ni(111), njengoba kubikwe ngaphambilini30,46. Kunomehluko omkhulu ekubunjweni kwe-nickel foil phakathi kwe-FS-NiA kanye ne-BS-NiA. Ukungalungi okuphezulu kwe-BS-NGF/Ni kungenxa yobuso obungapholishiwe be-BS-NiAR, obuhlala bungalungi kakhulu ngisho nangemva kokuncibilika (Isithombe SI3). Lolu hlobo lokuhlukaniswa kobuso ngaphambi kwenqubo yokukhula luvumela ukungalungi kwamafilimu e-graphene kanye ne-graphite ukuthi kulawulwe. Kufanele kuqashelwe ukuthi i-substrate yokuqala yahlelwa kabusha kokusanhlamvu ngesikhathi sokukhula kwe-graphene, okwanciphisa kancane usayizi wokusanhlamvu futhi kwakhulisa kancane ukungalungi kobuso be-substrate uma kuqhathaniswa ne-annealed foil kanye ne-catalyst film22.
Ukulungisa kahle ubulukhuni bomphezulu we-substrate, isikhathi sokufaka i-annealing (usayizi wezinhlamvu)30,47 kanye nokulawula ukukhululwa43 kuzosiza ukunciphisa ukufana kobukhulu be-NGF besifunda esikalini esingu-µm2 kanye/noma ngisho ne-nm2 (okungukuthi, ukushintshashintsha kobukhulu bama-nanometer ambalwa). Ukulawula ubulukhuni bomphezulu we-substrate, izindlela ezifana nokupholisha nge-electrolytic kwe-nickel foil ephumayo zingacatshangelwa48. I-nickel foil elungisiwe ngaphambilini ingabe isifakwa i-anneal ekushiseni okuphansi (<900 °C)46 kanye nesikhathi (<5 min) ukugwema ukwakheka kwezinhlayiya ezinkulu ze-Ni(111) (okuzuzisa ukukhula kwe-FLG).
I-SLG kanye ne-FLG graphene ayikwazi ukumelana nokucindezelwa kobuso kwama-asidi namanzi, okudinga izendlalelo zokusekela ngomshini ngesikhathi sezinqubo zokudlulisa amakhemikhali ezimanzi22,34,38. Ngokungafani nokudluliselwa kwamakhemikhali okumanzi kwe-graphene eyodwa esekelwa yi-polymer, sithole ukuthi izinhlangothi zombili ze-NGF ekhulile zingadluliselwa ngaphandle kokusekelwa yi-polymer, njengoba kuboniswe kuMfanekiso 2a (bheka uMfanekiso SI4a ukuthola imininingwane eyengeziwe). Ukudluliselwa kwe-NGF ku-substrate ethile kuqala ngokuqoshwa okumanzi kwefilimu engaphansi kwe-Ni30.49. Amasampula e-NGF/Ni/NGF akhulile abekwe ubusuku bonke ku-15 mL we-70% HNO3 exutshwe ne-600 mL yamanzi a-deionized (DI). Ngemva kokuba i-Ni foil incibilike ngokuphelele, i-FS-NGF ihlala ithambekile futhi intanta phezu koketshezi, njengesampula ye-NGF/Ni/NGF, kuyilapho i-BS-NGF icwiliswa emanzini (Umfanekiso 2a,b). I-NGF ehlukanisiwe yabe isidluliselwa kusuka kwelinye ibhekha equkethe amanzi amasha acwengekile yayiswa kwelinye ibhekha futhi i-NGF ehlukanisiwe yagezwa kahle, iphindaphindwa izikhathi ezine kuya kweziyisithupha esitsheni sengilazi esigobile. Ekugcineni, i-FS-NGF kanye ne-BS-NGF zabekwa endaweni efiselekayo (Isithombe 2c).
Inqubo yokudlulisa amakhemikhali amanzi angena-polymer ye-NGF ekhuliswe ku-nickel foil: (a) Umdwebo wokugeleza kwenqubo (bheka uMfanekiso SI4 ukuthola imininingwane eyengeziwe), (b) Isithombe sedijithali se-NGF ehlukanisiwe ngemva kokuqoshwa kwe-Ni (amasampula ama-2), (c) Isibonelo sokudlulisa i-FS - kanye ne-BS-NGF ku-substrate ye-SiO2/Si, (d) ukudluliselwa kwe-FS-NGF ku-substrate ye-polymer engacacile, (e) i-BS-NGF kusuka kusampula efanayo nephaneli d (ehlukaniswe izingxenye ezimbili), idluliselwe ephepheni le-C elimbozwe ngegolide kanye ne-Nafion (substrate ecacile eguquguqukayo, imiphetho ephawulwe ngamakhona abomvu).
Qaphela ukuthi ukudluliselwa kwe-SLG okwenziwa kusetshenziswa izindlela zokudlulisa amakhemikhali amanzi kudinga isikhathi sokucubungula esiphelele samahora angu-20-24. Ngobuchwepheshe bokudlulisa obungena-polymer obuboniswe lapha (Isithombe SI4a), isikhathi sokucubungula ukudluliselwa kwe-NGF sisonke sincishiswe kakhulu (cishe amahora angu-15). Inqubo iqukethe: (Isinyathelo 1) Lungisa isixazululo sokusika bese ubeka isampula kuso (~imizuzu eyi-10), bese ulinda ubusuku bonke ukusika kwe-Ni (~imizuzu engu-7200), (Isinyathelo 2) Hlanza ngamanzi ahlanziwe (Isinyathelo - 3). gcina emanzini ahlanziwe noma udlulisele ku-substrate eqondiwe (imizuzu engama-20). Amanzi abanjwe phakathi kwe-NGF kanye ne-bulk matrix asuswa ngesenzo se-capillary (kusetshenziswa iphepha lokubhula)38, bese amaconsi amanzi asele asuswa ngokomiswa kwemvelo (cishe imizuzu engama-30), bese ekugcineni isampula yomiswa imizuzu eyi-10 kuhhavini we-vacuum (10-1 mbar) ku-50-90 °C (imizuzu engama-60)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, kanye ne-XRD ngemuva kokugcinwa emanzini acwebezelwe ekamelweni lokushisa kanye nasemabhodleleni avalwe isikhathi esisukela ezinsukwini ezimbalwa kuya onyakeni owodwa (Isithombe SI4). Akukho ukuwohloka okubonakalayo. Isibalo 2c sibonisa i-FS-NGF kanye ne-BS-NGF ezimele ngokukhululekile emanzini acwebezelwe. Sizithwebule ku-SiO2 (300 nm)/Si substrate, njengoba kuboniswe ekuqaleni kwesithombe 2c. Ngaphezu kwalokho, njengoba kuboniswe kusithombe 2d,e, i-NGF eqhubekayo ingadluliselwa kuma-substrate ahlukahlukene njenge-polymers (i-Thermabright polyamide evela ku-Nexolve kanye ne-Nafion) kanye nephepha le-carbon elimbozwe ngegolide. I-FS-NGF entantayo yabekwa kalula ku-substrate eqondiwe (Isithombe 2c, d). Kodwa-ke, amasampula e-BS-NGF amakhulu kuno-3 cm2 ayenzima ukuwaphatha lapho ecwiliswa ngokuphelele emanzini. Ngokuvamile, uma ziqala ukugingqika emanzini, ngenxa yokuphathwa ngokunganaki ngezinye izikhathi zihlukana zibe izingxenye ezimbili noma ezintathu (Isithombe 2e). Sekukonke, sikwazile ukufeza ukudluliselwa okungena-polymer kwe-PS- kanye ne-BS-NGF (ukudluliselwa okuqhubekayo okungenamthungo ngaphandle kokukhula kwe-NGF/Ni/NGF ku-6 cm2) kwamasampula afinyelela ku-6 kanye no-3 cm2 endaweni, ngokulandelana. Noma yiziphi izingcezu ezinkulu noma ezincane ezisele zingabonakala (kalula esixazululweni sokusika noma emanzini ahlanjululwe) ku-substrate oyifunayo (~1 mm2, Umfanekiso SI4b, bheka isampula edluliselwe kugridi yethusi njengaku-“FS-NGF: Isakhiwo kanye Nezakhiwo (okuxoxwe ngazo) ngaphansi kwe-“Isakhiwo kanye Nezakhiwo”) noma zigcinwe ukuze zisetshenziswe esikhathini esizayo (Isithombe SI4). Ngokusekelwe kulo mbandela, silinganisela ukuthi i-NGF ingatholakala ngesivuno esifinyelela ku-98-99% (ngemuva kokukhula kokudluliselwa).
Amasampula okudlulisa angenayo i-polymer ahlaziywe ngokuningiliziwe. Izici zokwakheka kwendawo ezitholakala ku-FS- kanye ne-BS-NGF/SiO2/Si (Isithombe 2c) kusetshenziswa i-optical microscopy (OM) kanye nezithombe ze-SEM (Isithombe SI5 kanye nesithombe 3) zibonise ukuthi lawa masampula adluliselwe ngaphandle kwe-microscopy. Umonakalo wesakhiwo obonakalayo njengemifantu, imigodi, noma izindawo ezivuliwe. Ama-fold ku-NGF ekhulayo (Isithombe 3b, d, amakwe ngemicibisholo ensomi) ahlala engashintshi ngemva kokudluliselwa. Zombili ama-FS- kanye ne-BS-NGF akhiwe yizifunda ze-FLG (izifunda ezikhanyayo ezikhonjiswe ngemicibisholo eluhlaza okwesibhakabhaka ku-Isithombe 3). Ngokumangazayo, ngokungafani nezifunda ezimbalwa ezonakele ezivame ukubonwa ngesikhathi sokudluliselwa kwe-polymer kwamafilimu e-graphite amancane kakhulu, izifunda eziningana ze-FLG kanye ne-MLG ezinobukhulu be-micron ezixhuma ku-NGF (ezimakwe ngemicibisholo eluhlaza okwesibhakabhaka ku-Isithombe 3d) zidluliselwe ngaphandle kwemifantu noma ukuphuka (Isithombe 3d). 3). Ubuqotho bomshini buqinisekiswe ngokwengeziwe kusetshenziswa izithombe ze-TEM kanye ne-SEM ze-NGF ezidluliselwe kumagridi ethusi e-lace-carbon, njengoba kuxoxwe kamuva (“FS-NGF: Isakhiwo kanye Nezakhiwo”). I-BS-NGF/SiO2/Si edluliselwe ilukhuni kune-FS-NGF/SiO2/Si enamanani e-rms angu-140 nm kanye no-17 nm, ngokulandelana, njengoba kuboniswe ku-Figure SI6a kanye no-b (20 × 20 μm2). Inani le-RMS le-NGF elidluliselwe kwi-substrate ye-SiO2/Si (RMS < 2 nm) liphansi kakhulu (cishe izikhathi ezi-3) kunele-NGF ekhuliswe ku-Ni (Figure SI2), okubonisa ukuthi ubulukhuni obengeziwe bungahambisana nobuso be-Ni. Ngaphezu kwalokho, izithombe ze-AFM ezenziwe emaphethelweni amasampula e-FS- kanye ne-BS-NGF/SiO2/Si zibonise ubukhulu be-NGF obungu-100 no-80 nm, ngokulandelana (Fig. SI7). Ubulukhuni obuncane be-BS-NGF bungaba umphumela wobuso obungavezwanga ngqo kugesi ongaphambili.
I-NGF edluliselwe (i-NiAG) ngaphandle kwe-polymer ku-SiO2/Si wafer (bheka uMfanekiso 2c): (a,b) Izithombe ze-SEM ze-FS-NGF edluliselwe: ukukhulisa okuphansi nokuphezulu (okuhambisana nesikwele esiwolintshi kuphaneli). Izindawo ezijwayelekile) – a). (c,d) Izithombe ze-SEM ze-BS-NGF edluliselwe: ukukhulisa okuphansi nokuphezulu (okuhambisana nendawo ejwayelekile eboniswe yisikwele esiwolintshi kuphaneli c). (e, f) Izithombe ze-AFM zama-FS- kanye nama-BS-NGF adluliselwe. Umcibisholo oluhlaza okwesibhakabhaka umele isifunda se-FLG – ukungafani okukhanyayo, umcibisholo we-cyan – ukungafani okumnyama kwe-MLG, umcibisholo obomvu – ukungafani okumnyama kumelela isifunda se-NGF, umcibisholo we-magenta umele ukugoqa.
Ukwakheka kwamakhemikhali kwama-FS- kanye nama-BS-NGF akhulisiwe nadlulisiwe kuhlaziywe nge-X-ray photoelectron spectroscopy (XPS) (Isithombe 4). I-peak ebuthakathaka ibonwe kuma-spectra alinganisiwe (Isithombe 4a, b), okuhambisana ne-substrate ye-Ni (850 eV) yama-FS- kanye nama-BS-NGF akhulisiwe (i-NiAG). Azikho iziqongo kuma-spectra alinganisiwe ama-FS- kanye nama-BS-NGF/SiO2/Si adluliselwe (Isithombe 4c; imiphumela efanayo ye-BS-NGF/SiO2/Si ayiboniswa), okubonisa ukuthi akukho ukungcoliswa kwe-Ni okusele ngemva kokudluliselwa. Izibalo 4d-f zibonisa ama-spectra anesinqumo esiphezulu samazinga wamandla e-C1 s, O1 s kanye ne-Si 2p e-FS-NGF/SiO2/Si. Amandla okubopha e-C1 s ye-graphite angama-284.4 eV53.54. Ukuma okuqondile kweziqongo ze-graphite ngokuvamile kubhekwa njengokungalingani, njengoba kuboniswe ku-Figure 4d54. I-spectrum ye-C1 s yezinga eliphezulu lesisombululo (Isithombe 4d) nayo iqinisekisile ukudluliselwa okumsulwa (okungukuthi, akukho zinsalela ze-polymer), okuhambisana nezifundo zangaphambilini38. Ububanzi bemigqa ye-spectra ye-C1 s yesampula esanda kukhula (i-NiAG) kanye nokudluliselwa ngemuva kwayo kungu-0.55 kanye no-0.62 eV, ngokulandelana. Lawa manani aphezulu kunalawo e-SLG (0.49 eV ye-SLG ku-substrate ye-SiO2)38. Kodwa-ke, lawa manani mancane kunama-linewidth abikiwe ngaphambilini kumasampula e-graphene e-pyrolytic aqondiswe kakhulu (~0.75 eV)53,54,55, okubonisa ukungabikho kwezindawo zekhabhoni ezinephutha ezintweni zamanje. Ama-spectra e-C1 s kanye ne-O1 s wezinga lomhlaba nawo awanamahlombe, okususa isidingo sokususa i-peak ephezulu yesinqumo54. Kukhona i-satellite peak engu-π → π* ezungeze i-291.1 eV, evame ukubonwa kumasampula e-graphite. Izimpawu ze-103 eV kanye ne-532.5 eV ku-Si 2p kanye ne-O1 s core level spectra (bheka uMfanekiso 4e, f) zihlotshaniswa ne-substrate ye-SiO2 56, ngokulandelana. I-XPS iyindlela yokuzwela ebusweni, ngakho-ke izimpawu ezihambisana ne-Ni kanye ne-SiO2 ezitholwe ngaphambi nangemva kokudluliswa kwe-NGF, ngokulandelana, kucatshangwa ukuthi zivela esifundeni se-FLG. Imiphumela efanayo yabonwa kumasampula e-BS-NGF adluliselwe (awaboniswanga).
Imiphumela ye-NiAG XPS: (ac) Hlola ama-spectra ezinhlobo ezahlukene ze-athomu ye-elemental ye-FS-NGF/Ni ekhulile, i-BS-NGF/Ni bese idluliselwa i-FS-NGF/SiO2/Si, ngokulandelana. (d–f) Ama-spectra anesinqumo esiphezulu samazinga ayinhloko C 1 s, O 1s kanye ne-Si 2p yesampula ye-FS-NGF/SiO2/Si.
Ikhwalithi iyonke yamakristalu e-NGF adluliselwe ihlolwe kusetshenziswa i-X-ray diffraction (XRD). Amaphethini ajwayelekile e-XRD (Isithombe SI8) sama-FS- kanye ne-BS-NGF/SiO2/Si adluliselwe abonisa ukuba khona kweziqongo ze-diffraction (0 0 0 2) kanye (0 0 0 4) ku-26.6° kanye no-54.7°, okufana ne-graphite. . Lokhu kuqinisekisa ikhwalithi ephezulu ye-crystalline ye-NGF futhi kuhambisana nebanga eliphakathi kwe-d = 0.335 nm, eligcinwa ngemuva kwesinyathelo sokudlulisa. Ukuqina kwe-diffraction peak (0 0 0 2) cishe kuphindwe izikhathi ezingu-30 kune-diffraction peak (0 0 0 4), okubonisa ukuthi indiza yekristalu ye-NGF ihambisana kahle nobuso besampula.
Ngokusho kwemiphumela ye-SEM, i-Raman spectroscopy, i-XPS kanye ne-XRD, ikhwalithi ye-BS-NGF/Ni itholakale ifana neye-FS-NGF/Ni, yize ubulukhuni bayo be-rms babuphakeme kancane (Izibalo SI2, SI5) kanye ne-SI7).
Ama-SLG anezendlalelo zokusekela i-polymer ezifika ku-200 nm ubukhulu angantanta emanzini. Lokhu kusethwa kuvame ukusetshenziswa ezinqubweni zokudlulisa amakhemikhali amanzi assisted polymer22,38. I-Graphene ne-graphite azinawo umoya (i-wet angle 80–90°) 57. Izindawo zamandla ezingaba khona ze-graphene ne-FLG zibikwe njengeziyisicaba impela, zinamandla angaba mandla aphansi (~1 kJ/mol) okunyakaza kwamanzi eceleni kobuso58. Kodwa-ke, amandla okusebenzisana abaliwe amanzi ne-graphene kanye nezendlalelo ezintathu ze-graphene cishe angama-−13 kanye nama-−15 kJ/mol,58 ngokulandelana, okubonisa ukuthi ukusebenzisana kwamanzi ne-NGF (cishe izendlalelo ezingama-300) kuphansi uma kuqhathaniswa ne-graphene. Lokhu kungaba esinye sezizathu ezenza i-NGF ehlala iyisicaba phezu kwamanzi, kuyilapho i-graphene ehlala iyisicaba (entanta emanzini) igoqeka futhi iqhekeke. Lapho i-NGF icwiliswe ngokuphelele emanzini (imiphumela iyafana ne-NGF elukhuni futhi eyisicaba), imiphetho yayo iyagoba (Isithombe SI4). Uma kwenzeka ukucwiliswa ngokuphelele, kulindeleke ukuthi amandla okusebenzisana kwamanzi ne-NGF acishe aphindwe kabili (uma kuqhathaniswa ne-NGF entantayo) nokuthi imiphetho ye-NGF igoqeke ukuze kulondolozwe i-engeli yokuxhumana ephezulu (ukwesaba amanzi). Sikholelwa ukuthi amasu angathuthukiswa ukuze kugwenywe ukugoba kwemiphetho ye-NGF efakiwe. Enye indlela ukusebenzisa izinyibilikisi ezixubile ukuze kulungiswe ukusabela kokumanzisa kwefilimu ye-graphite59.
Ukudluliswa kwe-SLG ezinhlotsheni ezahlukene ze-substrate ngezinqubo zokudlulisa amakhemikhali amanzi kuye kwabikwa ngaphambilini. Ngokuvamile kuyamukelwa ukuthi amandla abuthakathaka e-van der Waals akhona phakathi kwamafilimu e-graphene/graphite kanye ne-substrate (kungaba yi-substrate eqinile njenge-SiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 kanye ne-lacy carbon films30, 34 noma i-flexible substrates njenge-polyimide 37). Lapha sicabanga ukuthi ukusebenzisana kohlobo olufanayo kuyabusa. Asibonanga noma yikuphi ukulimala noma ukuqhekeka kwe-NGF kunoma yiziphi i-substrate ezethulwe lapha ngesikhathi sokuphathwa kwemishini (ngesikhathi sokuchazwa ngaphansi kwe-vacuum kanye/noma izimo zomkhathi noma ngesikhathi sokugcina) (isb., Umfanekiso 2, SI7 kanye ne-SI9). Ngaphezu kwalokho, asibonanga ukuphakama kwe-SiC ku-XPS C1 s spectrum yezinga eliyinhloko lesampula ye-NGF/SiO2/Si (Umfanekiso 4). Le miphumela ikhombisa ukuthi akukho sibopho samakhemikhali phakathi kwe-NGF kanye ne-substrate eqondiwe.
Esigabeni esidlule, “Ukudluliswa kwe-FS- kanye ne-BS-NGF okungena-polymer,” sibonise ukuthi i-NGF ingakhula futhi idlulisele kuzo zombili izinhlangothi ze-nickel foil. Lawa ma-FS-NGF kanye nama-BS-NGF awafani ngokwezinga lokungalungi kobuso, okwasishukumisela ukuthi sihlole izinhlelo zokusebenza ezifanele kakhulu zohlobo ngalunye.
Uma sibheka ukucaca kanye nobuso obubushelelezi be-FS-NGF, sifunde isakhiwo sayo sendawo, izakhiwo ze-optical kanye ne-electric ngokuningiliziwe. Isakhiwo kanye nesakhiwo se-FS-NGF ngaphandle kokudluliselwa kwe-polymer kwaphawulwa nge-transmission electron microscopy (TEM) imaging kanye nokuhlaziywa kwephethini ye-electron diffraction yendawo ekhethiwe (SAED). Imiphumela ehambisanayo iboniswe ku-Figure 5. I-low magnification planar TEM imaging iveze ukuba khona kwezifunda ze-NGF kanye ne-FLG ezinezimpawu ezahlukene zokungafani kwama-electron, okungukuthi izindawo ezimnyama nezikhanyayo, ngokulandelana (Fig. 5a). Ifilimu iyonke ikhombisa ubuqotho obuhle bomshini kanye nokuqina phakathi kwezifunda ezahlukene ze-NGF kanye ne-FLG, ngokugqagqana okuhle futhi akukho monakalo noma ukudabuka, okuqinisekiswe yi-SEM (Figure 3) kanye nezifundo ze-TEM zokukhulisa okuphezulu (Figure 5c-e). Ikakhulukazi, ku-Fig. Figure 5d ikhombisa isakhiwo sebhuloho engxenyeni yaso enkulu (indawo ephawulwe umcibisholo onamachashazi amnyama ku-Figure 5d), ephawulwa ngesimo esingunxantathu futhi iqukethe ungqimba lwe-graphene olunobubanzi obungaba ngu-51. Ukwakheka okunesikhala esiphakathi kwe-0.33 ± 0.01 nm kuncishiswa kakhulu kube yizingqimba eziningana ze-graphene esifundeni esincane kakhulu (ukuphela komcibisholo omnyama oqinile kuMfanekiso 5 d).
Isithombe se-Planar TEM sesampula ye-NiAG engena-polymer kugridi yethusi ye-carbon lacy: (a, b) Izithombe ze-TEM ezikhulisa kancane ezifaka phakathi izifunda ze-NGF ne-FLG, (ce) Izithombe ezikhulisa kakhulu zezifunda ezahlukene kuphaneli-a nakuphaneli-b ziyimicibisholo ephawuliwe enombala ofanayo. Imicibisholo eluhlaza kumaphaneli a no-c ikhombisa izindawo eziyindilinga zomonakalo ngesikhathi sokulungiswa kwemisebe. (f–i) Kumaphaneli a kuya ku-c, amaphethini e-SAED ezifundeni ezahlukene aboniswa ngemibuthano eluhlaza okwesibhakabhaka, i-cyan, i-orenji, kanye nebomvu, ngokulandelana.
Isakhiwo seribhoni kuMfanekiso 5c sibonisa (okuphawulwe ngomcibisholo obomvu) ukuqondiswa okuqondile kwezindiza ze-graphite lattice, okungase kube ngenxa yokwakheka kwama-nanofolds eceleni kwefilimu (okufakiwe kuMfanekiso 5c) ngenxa yokucindezeleka okukhulu kwe-shear okungakhokhelwa30,61,62. Ngaphansi kwe-TEM enesinqumo esiphezulu, la ma-nanofolds 30 abonisa ukuqondiswa okuhlukile kwe-crystallographic kunezinye izindawo ze-NGF; izindawo eziyisisekelo ze-graphite lattice ziqondiswe cishe ngokuqondile, kunokuba ziqonde ngqo njengazo zonke ezinye izindawo zefilimu (okufakiwe kuMfanekiso 5c). Ngokufanayo, isifunda se-FLG ngezinye izikhathi sibonisa ama-fold afana ne-linear ne-minimal band (aphawulwe ngemicibisholo eluhlaza okwesibhakabhaka), avela ekukhulisweni okuphansi nokuphakathi kuMfanekiso 5b, 5e, ngokulandelana. Okufakiwe kuMfanekiso 5e kuqinisekisa ukuba khona kwezingqimba ze-graphene ezimbili nezingqimba ezintathu emkhakheni we-FLG (ibanga eliphakathi 0.33 ± 0.01 nm), okuvumelana kahle nemiphumela yethu yangaphambilini30. Ngaphezu kwalokho, izithombe ze-SEM eziqoshiwe ze-NGF engena-polymer ezidluliselwe kumagridi ethusi anamafilimu e-lacy carbon (ngemuva kokwenza izilinganiso ze-TEM ezibukwa phezulu) ziboniswe ku-Figure SI9. Isifunda se-FLG esimiswe kahle (esimakwe ngomcibisholo oluhlaza okwesibhakabhaka) kanye nesifunda esiphukile ku-Figure SI9f. Umcibisholo oluhlaza okwesibhakabhaka (emaphethelweni e-NGF edluliselwe) wethulwa ngamabomu ukukhombisa ukuthi isifunda se-FLG singamelana nenqubo yokudlulisa ngaphandle kwe-polymer. Ngamafuphi, lezi zithombe ziqinisekisa ukuthi i-NGF emiswe kancane (kufaka phakathi isifunda se-FLG) igcina ubuqotho bomshini ngisho nangemva kokuphathwa kanzima kanye nokuvezwa ku-vacuum ephezulu ngesikhathi sokulinganisa kwe-TEM kanye ne-SEM (Figure SI9).
Ngenxa yokuba yisicaba okuhle kakhulu kwe-NGF (bheka uMfanekiso 5a), akunzima ukuqondisa ama-flakes eceleni kwe-[0001] domain axis ukuze kuhlaziywe isakhiwo se-SAED. Kuye ngobukhulu bendawo befilimu nendawo yayo, izifunda eziningana ezithakazelisayo (amaphuzu angu-12) zahlonzwa ngezifundo ze-electron diffraction. KuMifanekiso 5a–c, ezine zalezi zifunda ezijwayelekile ziboniswa futhi zimakwe ngezindilinga ezinemibala (eluhlaza okwesibhakabhaka, i-cyan, i-orenji, nebomvu ezibhalwe ikhodi). Izibalo 2 no-3 zemodi ye-SAED. Izibalo 5f no-g zitholwe esifundeni se-FLG esiboniswe kuMifanekiso 5 no-5. Njengoba kuboniswe kuMifanekiso 5b no-c, ngokulandelana. Zinesakhiwo esinama-hexagonal esifana ne-graphene esontekile63. Ikakhulukazi, uMfanekiso 5f ukhombisa amaphethini amathathu abekwe ngaphezulu anombono ofanayo we-[0001] zone axis, ejikelezwe ngu-10° no-20°, njengoba kufakazelwa ukungafani kwe-angular kwama-pair amathathu okubonakaliswa (10-10). Ngokufanayo, uMfanekiso 5g ukhombisa amaphethini amabili ayisithupha abekwe phezulu ajikelezwe ngo-20°. Amaqembu amabili noma amathathu amaphethini ayisithupha esifundeni se-FLG angavela ezingqimbeni ezintathu ze-graphene ezingaphakathi noma ezingaphandle kwendiza ezingama-33 ezijikelezwe ngokuqondene nomunye nomunye. Ngokuphambene nalokho, amaphethini okusabalalisa ama-electron kuMfanekiso 5h, i (okuhambisana nesifunda se-NGF esiboniswe kuMfanekiso 5a) abonisa iphethini eyodwa [0001] enamandla aphezulu okusabalalisa iphuzu, okuhambisana nobukhulu obukhulu bezinto ezibonakalayo. Lawa mamodeli e-SAED ahambisana nesakhiwo se-graphitic esijiyile kanye nokuma okuphakathi kune-FLG, njengoba kunqunywe ku-index 64. Ukuchazwa kwezakhiwo ze-crystalline ze-NGF kwembule ukuba khona kwamakristalu amabili noma amathathu abekwe phezulu e-graphite (noma i-graphene). Okuphawuleka kakhulu esifundeni se-FLG ukuthi amakristalu anezinga elithile lokungaziqondi kahle ngaphakathi noma ngaphandle kwendiza. Izinhlayiya/izendlalelo ze-graphite ezine-engeli yokujikeleza ngaphakathi kwendiza engu-17°, 22° kanye no-25° ziye zabikwa ngaphambilini nge-NGF ekhuliswe kumafilimu e-Ni 64. Amanani e-engeli yokujikeleza abonwe kulolu cwaningo ahambisana nama-engeli okujikeleza abonwe ngaphambilini (±1°) e-graphene ye-BLG63 esontekile.
Izakhiwo zikagesi ze-NGF/SiO2/Si zilinganiswe ku-300 K endaweni engu-10×3 mm2. Amanani okuhlushwa kwe-electron carrier, ukuhamba kanye nokuqhuba kwe-conductivity angu-1.6 × 1020 cm-3, 220 cm2 V-1 C-1 kanye no-2000 S-cm-1, ngokulandelana. Amanani okuhlushwa kwe-mobility kanye nokuqhuba kwe-NGF yethu afana ne-graphite2 yemvelo futhi aphezulu kune-graphite ye-pyrolytic etholakala kwezentengiselwano (ekhiqizwa ku-3000 °C)29. Amanani okuhlushwa kwe-electron carrier abonwe angama-oda amabili aphezulu kunalawo abikwe muva nje (7.25 × 10 cm-3) amafilimu e-graphite obukhulu be-micron alungiselelwe kusetshenziswa amashidi e-polyimide okushisa okuphezulu (3200 °C) 20.
Siphinde senza izilinganiso zokudlulisa ezibonakalayo ze-UV ku-FS-NGF edluliselwe kuma-substrate e-quartz (Isithombe 6). I-spectrum ephumelayo ikhombisa ukudlulisa okucishe kufane okungu-62% ebangeni elingu-350–800 nm, okubonisa ukuthi i-NGF ikhanya ekukhanyeni okubonakalayo. Eqinisweni, igama elithi “KAUST” lingabonakala esithombeni sedijithali sesampula ku-Figure 6b. Nakuba isakhiwo se-nanocrystalline se-NGF sihlukile kwese-SLG, inani lezingqimba lingalinganiselwa cishe kusetshenziswa umthetho wokulahlekelwa kokudluliselwa okungu-2.3% ngengqimba eyengeziwe65. Ngokusho kwalobu budlelwano, inani lezingqimba ze-graphene ezinokulahlekelwa kokudluliselwa okungu-38% lingu-21. I-NGF ekhulile ikakhulukazi iqukethe izingqimba ze-graphene ezingu-300, okungukuthi cishe ubukhulu obungu-100 nm (Isithombe 1, SI5 kanye ne-SI7). Ngakho-ke, sicabanga ukuthi ukukhanya okubonakalayo okubonakalayo kufana nezifunda ze-FLG kanye ne-MLG, njengoba zisakazwa kulo lonke ifilimu (Izithombe 1, 3, 5 kanye no-6c). Ngaphezu kwedatha yesakhiwo engenhla, ukuhanjiswa kwamandla kanye nokucaca nakho kuqinisekisa ikhwalithi ephezulu yekristalu ye-NGF edluliselwe.
(a) Ukulinganiswa kokudluliselwa okubonakalayo kwe-UV, (b) ukudluliselwa okuvamile kwe-NGF ku-quartz kusetshenziswa isampula emele. (c) I-schematic ye-NGF (ibhokisi elimnyama) enezifunda ze-FLG ne-MLG ezisatshalaliswe ngokulinganayo ezimakwe njengezimo ezingahleliwe ezimpunga kulo lonke isampula (bheka uMfanekiso 1) (cishe indawo engu-0.1–3% ku-100 μm2). Izimo ezingahleliwe kanye nosayizi wazo kumdwebo zenzelwe izinjongo zokubonisa kuphela futhi azihambisani nezindawo zangempela.
I-NGF ekhanyayo ekhuliswe yi-CVD idluliselwe ezindaweni ze-silicon ezingenalutho futhi isetshenziswa kumaseli elanga15,16. Ukusebenza kahle kokuguqulwa kwamandla (PCE) okubangelwayo kungu-1.5%. Lawa ma-NGF enza imisebenzi eminingi njengezingqimba ezisebenzayo, izindlela zokuthutha zokushaja, kanye nama-electrode abonakalayo15,16. Kodwa-ke, ifilimu ye-graphite ayifani. Ukulungiswa okwengeziwe kuyadingeka ngokulawula ngokucophelela ukumelana kweshidi kanye nokudluliselwa kwe-optical kwe-graphite electrode, njengoba lezi zakhiwo ezimbili zidlala indima ebalulekile ekunqumeni inani le-PCE leseli lelanga15,16. Ngokuvamile, amafilimu e-graphene abonakala ngo-97.7% ekukhanyeni okubonakalayo, kodwa anokumelana kweshidi okungu-200–3000 ohms/sq.16. Ukumelana kobuso bamafilimu e-graphene kungancishiswa ngokwandisa inani lezingqimba (ukudluliselwa okuningi kwezingqimba ze-graphene) kanye nokufaka i-doping nge-HNO3 (~30 Ohm/sq.)66. Kodwa-ke, le nqubo ithatha isikhathi eside futhi izingqimba ezahlukene zokudlulisa azihlali zigcina ukuxhumana okuhle. I-NGF yethu engaphambili inezakhiwo ezifana nokuqhuba okungu-2000 S/cm, ukumelana neshidi lefilimu elingu-50 ohm/sq. kanye nokucaca okungu-62%, okwenza kube yindlela engcono kakhulu yeziteshi zokuqhuba noma ama-counter electrode kumaseli elanga15,16.
Nakuba isakhiwo kanye ne-chemistry engaphezulu ye-BS-NGF kufana ne-FS-NGF, ubulukhuni bayo buhlukile (“Ukukhula kwe-FS- kanye ne-BS-NGF”). Ngaphambilini, besisebenzisa i-graphite yefilimu encane kakhulu22 njengenzwa yegesi. Ngakho-ke, sihlole ukuthi kungenzeka yini ukusebenzisa i-BS-NGF emisebenzini yokuzwa igesi (Isithombe SI10). Okokuqala, izingxenye ze-BS-NGF ezinobukhulu be-mm2 zadluliselwa ku-chip yenzwa ye-electrode ehlanganisa ama-digitating (Isithombe SI10a-c). Imininingwane yokukhiqiza ye-chip ibikwe ngaphambilini; indawo yayo ebucayi esebenzayo ingu-9 mm267. Ezithombeni ze-SEM (Isithombe SI10b kanye no-c), i-electrode yegolide engaphansi ibonakala ngokucacile nge-NGF. Futhi, kungabonakala ukuthi ukumbozwa kwe-chip efanayo kufezwe kuwo wonke amasampula. Ukulinganiswa kwenzwa yegesi yamagesi ahlukahlukene kuqoshwe (Isithombe SI10d) (Isithombe SI11) kanye namazinga okuphendula aphumela kukhonjiswa ku-Figs. SI10g. Cishe ngezinye izigesi eziphazamisayo kufaka phakathi i-SO2 (200 ppm), i-H2 (2%), i-CH4 (200 ppm), i-CO2 (2%), i-H2S (200 ppm) kanye ne-NH3 (200 ppm). Esinye isizathu esingaba khona yi-NO2. i-electrophilic yemvelo yegesi22,68. Uma ifakwa ebusweni be-graphene, inciphisa ukumuncwa kwamanje kwama-electron yisistimu. Ukuqhathaniswa kwedatha yesikhathi sokuphendula yenzwa ye-BS-NGF nezinzwa ezishicilelwe ngaphambilini kwethulwe kuThebula SI2. Indlela yokuvuselela izinzwa ze-NGF kusetshenziswa i-UV plasma, i-O3 plasma noma ukwelashwa kwe-thermal (50–150°C) kwamasampula avele eveziwe iyaqhubeka, okungcono kulandelwe ukusetshenziswa kwezinhlelo ezifakiwe69.
Ngesikhathi senqubo ye-CVD, ukukhula kwe-graphene kwenzeka kuzo zombili izinhlangothi ze-catalyst substrate41. Kodwa-ke, i-BS-graphene ivame ukukhishwa ngesikhathi senqubo yokudlulisa41. Kulesi sifundo, sibonisa ukuthi ukukhula kwe-NGF kwekhwalithi ephezulu kanye nokudluliselwa kwe-NGF okungena-polymer kungatholakala kuzo zombili izinhlangothi zokusekelwa kwe-catalyst. I-BS-NGF incane (~80 nm) kune-FS-NGF (~100 nm), futhi lo mehluko uchazwa iqiniso lokuthi i-BS-Ni ayivezwanga ngqo ekugelezeni kwegesi okungaphambi kwesikhathi. Sithole nokuthi ukugoba kwe-substrate ye-NiAR kuthonya ukugoba kwe-NGF. Le miphumela ikhombisa ukuthi i-FS-NGF ekhulisiwe ehlanganisiwe ingasetshenziswa njengento yokwandulela i-graphene (ngendlela yokukhipha i-foliation70) noma njengesiteshi esiqhubayo kumaseli elanga15,16. Ngokuphambene nalokho, i-BS-NGF izosetshenziselwa ukuthola igesi (Umfanekiso SI9) futhi mhlawumbe nezinhlelo zokugcina amandla71,72 lapho ukugoba kwayo kobuso kuzoba wusizo khona.
Uma sibheka okungenhla, kuyasiza ukuhlanganisa umsebenzi wamanje namafilimu e-graphite ashicilelwe ngaphambilini akhuliswe yi-CVD kanye nokusebenzisa i-nickel foil. Njengoba kungabonakala kuThebula 2, ukucindezela okuphezulu esikusebenzisile kufinyeze isikhathi sokuphendula (isigaba sokukhula) ngisho nasemazingeni okushisa aphansi (ebangeni lika-850–1300 °C). Siphinde sathola ukukhula okukhulu kunokujwayelekile, okubonisa amathuba okwanda. Kunezinye izici okufanele sizicabangele, ezinye zazo esizifakile kuthebula.
I-NGF esezingeni eliphezulu enamacala amabili ikhuliswe ku-nickel foil nge-catalytic CVD. Ngokususa ama-polymer substrates endabuko (njengalawo asetshenziswa ku-CVD graphene), sifinyelela ukudluliselwa okumanzi kwe-NGF okuhlanzekile nokungenasici (okukhuliswe ngemuva nangaphambili kwe-nickel foil) kuya ezinhlobonhlobo ze-substrates ezibalulekile ngenqubo. Okuphawulekayo ukuthi i-NGF ifaka izifunda ze-FLG ne-MLG (ngokuvamile kusuka ku-0.1% kuya ku-3% nge-100 µm2) ezihlanganiswe kahle ngesakhiwo kufilimu ejiyile. I-Planar TEM ikhombisa ukuthi lezi zifunda zakhiwe yizinqwaba zezinhlayiya ezimbili kuya kwezintathu ze-graphite/graphene (amakristalu noma izendlalelo, ngokulandelana), ezinye zazo ezinokungalingani kokujikeleza okungu-10–20°. Izifunda ze-FLG ne-MLG zinomthwalo wokubonakala kwe-FS-NGF ekukhanyeni okubonakalayo. Ngokuphathelene namashidi angemuva, angathwalwa ngokuhambisana namashidi angaphambili futhi, njengoba kuboniswe, angaba nenhloso yokusebenza (isibonelo, ukuthola igesi). Lezi zifundo ziwusizo kakhulu ekunciphiseni imfucuza kanye nezindleko ezinqubweni ze-CVD zezinga lezimboni.
Ngokuvamile, ubukhulu obujwayelekile be-CVD NGF buphakathi kwamashidi e-graphene (aphansi nanezingqimba eziningi) kanye namashidi e-graphite ezimboni (ama-micrometer). Ububanzi bezakhiwo zawo ezithakazelisayo, kuhlanganiswe nendlela elula esiyisungulile yokukhiqizwa kwawo kanye nokuthuthwa kwawo, kwenza la mafilimu afaneleke kakhulu ezinhlelweni zokusebenza ezidinga impendulo esebenzayo ye-graphite, ngaphandle kwezindleko zezinqubo zokukhiqiza zezimboni ezisebenzisa amandla amaningi ezisetshenziswa njengamanje.
I-foil ye-nickel engu-25 μm ubukhulu (ubumsulwa obungu-99.5%, Goodfellow) ifakwe ku-reactor ye-CVD yezentengiselwano (i-Aixtron 4-inch BMPro). Uhlelo lwahlanzwa nge-argon lwasuswa lwayiswa kungcindezi eyisisekelo engu-10-3 mbar. Kwabe sekufakwa i-foil ye-nickel. ku-Ar/H2 (Ngemuva kokufaka i-foil ye-Ni imizuzu emi-5, i-foil yavezwa kungcindezi engu-500 mbar ku-900 °C. I-NGF yafakwa ekugelezeni kwe-CH4/H2 (100 cm3 ngayinye) imizuzu emi-5. Isampula yabe isipholiswa ekushiseni okungaphansi kuka-700 °C kusetshenziswa ukugeleza kwe-Ar (4000 cm3) ku-40 °C/min. Imininingwane yokwenza ngcono inqubo yokukhula kwe-NGF ichazwe kwenye indawo.
Ukwakheka kobuso besampula kwabonakala nge-SEM kusetshenziswa i-microscope ye-Zeiss Merlin (1 kV, 50 pA). Ubulukhuni bobuso besampula kanye nobukhulu be-NGF kwalinganiswa kusetshenziswa i-AFM (Dimension Icon SPM, Bruker). Ukulinganiswa kwe-TEM kanye ne-SAED kwenziwa kusetshenziswa i-microscope ye-FEI Titan 80–300 Cubed efakwe isibhamu sokukhipha insimu esikhanya kakhulu (300 kV), i-monochromator yohlobo lwe-FEI Wien kanye ne-CEOS lens spherical aberration corrector ukuthola imiphumela yokugcina. Isixazululo sendawo esingu-0.09 nm. Amasampula e-NGF adluliselwe kumagridi ethusi ahlanganiswe ne-carbon lacy ukuze kuthathwe izithombe ze-TEM ezisicaba kanye nokuhlaziywa kwesakhiwo se-SAED. Ngakho-ke, iningi lama-floc esampula lilengiswe ezimbotsheni ze-membrane esekelayo. Amasampula e-NGF adluliselwe ahlaziywa yi-XRD. Amaphethini okusabalalisa kwe-X-ray atholakale kusetshenziswa i-powder diffractometer (i-Brucker, i-D2 phase shifter enomthombo we-Cu Kα, i-1.5418 Å kanye ne-LYNXEYE detector) kusetshenziswa umthombo wokukhanya we-Cu onobubanzi be-beam spot obungu-3 mm.
Izilinganiso eziningana ze-Raman point zaqoshwa kusetshenziswa i-integrated confocal microscope (Alpha 300 RA, WITeC). I-laser engu-532 nm enamandla aphansi okuvuselela (25%) yasetshenziswa ukugwema imiphumela ebangelwa ukushisa. I-X-ray photoelectron spectroscopy (XPS) yenziwa ku-Kratos Axis Ultra spectrometer endaweni yesampula engu-300 × 700 μm2 kusetshenziswa imisebe ye-monochromatic Al Kα (hν = 1486.6 eV) ngamandla angu-150 W. Ama-resolution spectra atholwe ngamandla okudlulisa angu-160 eV kanye no-20 eV, ngokulandelana. Amasampula e-NGF adluliselwe ku-SiO2 anqunywa abe yizicucu (3 × 10 mm2 ngalinye) kusetshenziswa i-PLS6MW (1.06 μm) ytterbium fiber laser ku-30 W. Oxhumana nabo be-copper wire (50 μm ubukhulu) bakhiwe kusetshenziswa i-silver paste ngaphansi kwe-optical microscope. Ukuhlolwa kokuthutha kagesi kanye nomphumela we-Hall kwenziwe kulezi zibonelo ku-300 K kanye nokwehluka kwensimu yamagnetic ye-± 9 Tesla ohlelweni lokulinganisa izakhiwo zomzimba (PPMS EverCool-II, Quantum Design, USA). Ama-spectra e-UV-vis adluliselwe aqoshwa kusetshenziswa i-Lambda 950 UV-vis spectrophotometer ebangeni le-350-800 nm NGF adluliselwe kuma-substrate e-quartz kanye namasampula okubhekisela e-quartz.
Inzwa yokumelana namakhemikhali (i-chip ye-electrode ephakathi) yaxhunywa ebhodini lesifunda eliphrintiwe ngokwezifiso 73 futhi ukumelana kwakhishwa okwesikhashana. Ibhodi lesifunda eliphrintiwe lapho idivayisi ikhona khona lixhunywe kuma-terminal okuxhumana futhi lafakwa ngaphakathi kwegumbi lokuzwa igesi 74. Izilinganiso zokumelana zathathwa ku-voltage engu-1 V ngokuskena okuqhubekayo kusukela ekuhlanzeni kuya ekuvezweni kwegesi bese kuhlanzwa futhi. Ikamelo lahlanzwa ekuqaleni ngokuhlanzwa nge-nitrogen ku-200 cm3 ihora eli-1 ukuqinisekisa ukususwa kwazo zonke ezinye i-analytes ezikhona ekamelweni, kufaka phakathi umswakama. I-analytes ngayinye yabe isikhishwa kancane kancane ekamelweni ngesilinganiso esifanayo sokugeleza esingu-200 cm3 ngokuvala isilinda se-N2.
Inguqulo ebuyekeziwe yalesi sihloko ishicilelwe futhi ingafinyelelwa ngesixhumanisi esiphezulu sesihloko.
Inagaki, M. kanye noKang, F. Isayensi Nobunjiniyela Bezinto Zekhabhoni: Izisekelo. Uhlelo lwesibili luhlelwe. 2014. 542.
Pearson, HO Incwadi Yesandla Yekhabhoni, I-Graphite, Idayimane Nama-Fullerenes: Izakhiwo, Ukucubungula kanye Nezicelo. Uhlelo lokuqala luhlelwe. 1994, eNew Jersey.
UTsai, W. nabanye. Amafilimu e-graphene/graphite amaningi endawo enkulu njengama-electrode amancane aqondisa ugesi. isicelo. i-physics. Wright. 95(12), 123115(2009).
I-Balandin AA Izakhiwo zokushisa ze-graphene kanye nezinto ze-carbon ezakhiwe ngendlela encane. Nat. Matt. 10(8), 569–581 (2011).
UCheng KY, uBrown PW noCahill DG Ukushisa kwamafilimu e-graphite akhuliswe ku-Ni (111) ngokufakwa komphunga wamakhemikhali okushisa okuphansi. isithasiselo. Matt. Interface 3, 16 (2016).
UHesjedal, T. Ukukhula okuqhubekayo kwamafilimu e-graphene ngokufakwa komphunga wamakhemikhali. isicelo. i-physics. Wright. 98(13), 133106(2011).
Isikhathi sokuthunyelwe: Agasti-23-2024