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Iifilimu ze-graphite ze-nanoscale (ii-NGF) zizinto eziqinileyo ze-nanomaterials ezinokuveliswa yi-catalytic chemical vapor deposition, kodwa kusekho imibuzo malunga nokulula kwazo ukudluliselwa kunye nendlela i-surface morphology echaphazela ngayo ukusetyenziswa kwazo kwizixhobo zesizukulwana esilandelayo. Apha sixela ukukhula kwe-NGF kumacala omabini e-polycrystalline nickel foil (indawo engama-55 cm2, ubukhulu malunga ne-100 nm) kunye nokudluliselwa kwayo okungena-polymer (ngaphambili nangasemva, indawo ukuya kuthi ga kwi-6 cm2). Ngenxa ye-morphology ye-catalyst foil, iifilimu ezimbini ze-carbon zahlukile kwiimpawu zazo zomzimba kunye nezinye iimpawu (ezifana noburhabaxa bomphezulu). Sibonisa ukuba ii-NGF ezine-rougher backside zifanelekile ukubonwa kwe-NO2, ngelixa ii-NGF ezithambileyo neziqhuba ngakumbi kwicala langaphambili (2000 S/cm, ukumelana neshiti - 50 ohms/m2) zinokuba zii-conductors ezisebenzayo. itshaneli okanye i-electrode yeseli yelanga (kuba idlulisela i-62% yokukhanya okubonakalayo). Lilonke, iinkqubo zokukhula nezothutho ezichazwe apha zinokunceda ekufezekiseni i-NGF njengenye indlela yokusebenzisa ikhabhoni kwizicelo zobuchwepheshe apho iifilimu ze-graphene kunye ne-micron-thick graphite zingafanelekanga.
I-Graphite sisixhobo esisetyenziswa kakhulu kwimizi-mveliso. Okuphawulekayo kukuba, i-graphite ineempawu zobunzima obuphantsi kunye nokuqhuba okuphezulu kobushushu kunye nombane ngaphakathi, kwaye izinzile kakhulu kwiindawo ezishushu kakhulu kunye neekhemikhali1,2. I-Flake graphite sisixhobo sokuqala esaziwayo sophando lwe-graphene3. Xa icutshungulwa ibe ziifilimu ezincinci, ingasetyenziswa kwiintlobo ngeentlobo zezicelo, kubandakanya izinki zobushushu kwizixhobo ze-elektroniki ezifana nee-smartphone4,5,6,7, njengezinto ezisebenzayo kwiisensors8,9,10 kunye nokukhusela ukuphazamiseka kwe-electromagnetic11.12 kunye neefilimu ze-lithography kwi-ultraviolet extreme13,14, eziqhuba iziteshi kwiiseli zelanga15,16. Kuzo zonke ezi zicelo, kuya kuba yinzuzo enkulu ukuba iindawo ezinkulu zeefilimu ze-graphite (NGFs) ezinobukhulu obulawulwa kwi-nanoscale <100 nm zinokuveliswa kwaye zithuthwe ngokulula.
Iifilimu zegrafiti ziveliswa ngeendlela ezahlukeneyo. Kwimeko enye, ukubethelela kunye nokwandisa okulandelwa kukukhutshelwa ngaphandle kwamafutha kwasetyenziswa ukuvelisa iiflakes zegrafiti10,11,17. Iiflakes kufuneka zicutshungulwe ngakumbi zibe ziifilimu ezinobukhulu obufunekayo, kwaye kudla ngokuthatha iintsuku ezininzi ukuvelisa amaphepha egrafiti axineneyo. Enye indlela kukuqala ngee-graphitable solid precursors. Kwishishini, amaphepha eepolymers ayakhabhoni (kwi-1000–1500 °C) aze emva koko afakelwe iigrafiti (kwi-2800–3200 °C) ukuze kwenziwe izinto ezakhiwe kakuhle. Nangona umgangatho wezi filimu uphezulu, ukusetyenziswa kwamandla kubalulekile1,18,19 kwaye ubukhulu obuncinci bunqunyelwe kwii-microns ezimbalwa1,18,19,20.
I-Catalytic chemical vapor deposition (CVD) yindlela eyaziwayo yokuvelisa iifilimu ze-graphene kunye ne-ultrathin graphite (<10 nm) ezinomgangatho ophezulu wolwakhiwo kunye neendleko ezifanelekileyo21,22,23,24,25,26,27. Nangona kunjalo, xa kuthelekiswa nokukhula kweefilimu ze-graphene kunye ne-ultrathin graphite28, ukukhula kwendawo enkulu kunye/okanye ukusetyenziswa kwe-NGF kusetyenziswa i-CVD akuhlolisiswanga kangako11,13,29,30,31,32,33.
Iifilimu zegraphene kunye negrafiti ezikhuliswe nge-CVD zihlala zifuna ukudluliselwa kwi-substrates ezisebenzayo34. Olu dluliselo lwefilimu oluncinci lubandakanya iindlela ezimbini eziphambili35: (1) udluliselo olungatshiyo36,37 kunye (2) udluliselo lweekhemikhali ezimanzi olusekelwe kwi-etch (i-substrate exhaswayo)14,34,38. Indlela nganye ineenzuzo kunye neengxaki ezithile kwaye kufuneka ikhethwe ngokuxhomekeke kwisicelo esicetywayo, njengoko kuchaziwe kwenye indawo35,39. Kwiifilimu zegraphene/grafiti ezikhuliswe kwi-substrates ze-catalytic, udluliselo ngeenkqubo zeekhemikhali ezimanzi (apho i-polymethyl methacrylate (PMMA) yeyona maleko yenkxaso esetyenziswa kakhulu) luhlala lukhetho lokuqala13,30,34,38,40,41,42. Wena nabanye. Kukhankanyiwe ukuba akukho polymer isetyenziselwe ukudluliselwa kwe-NGF (ubungakanani besampulu malunga ne-4 cm2)25,43, kodwa akukho nkcukacha zinikiweyo malunga nokuzinza kwesampulu kunye/okanye ukuphathwa ngexesha lokudluliselwa; Iinkqubo zekhemistri ezimanzi ezisebenzisa iipolymers ziqulathe amanyathelo aliqela, kuquka ukusetyenziswa kunye nokususwa okulandelayo komaleko wepolymer oqingqiweyo30,38,40,41,42. Le nkqubo ineengxaki: umzekelo, iintsalela zepolymer zinokutshintsha iipropati zefilimu ekhulileyo38. Ukulungiswa okongeziweyo kunokususa ipolymer eseleyo, kodwa la manyathelo ongezelelweyo anyusa iindleko kunye nexesha lokuveliswa kwefilimu38,40. Ngexesha lokukhula kwe-CVD, umaleko wegraphene ubekwa kungekuphela nje kwicala langaphambili le-catalyst foil (icala elijongene nokuhamba komphunga), kodwa nakwicala lalo elingasemva. Nangona kunjalo, le yokugqibela ithathwa njengemveliso elahlekileyo kwaye inokususwa ngokukhawuleza yi-plasma ethambileyo38,41. Ukuphinda usebenzise le filimu kunokunceda ukwandisa isivuno, nokuba ikumgangatho ophantsi kunefilimu ye-carbon.
Apha, sixela ukulungiswa kokukhula kwe-NGF okune-wafer-scale bifacial kunye nomgangatho ophezulu wesakhiwo kwi-polycrystalline nickel foil yi-CVD. Kuhlolwe indlela uburhabaxa bomphezulu wangaphambili nowangasemva we-foil obuchaphazela ngayo imo kunye nolwakhiwo lwe-NGF. Sikwabonisa ukudluliselwa kwe-NGF okungenazo iipolymer ezingabizi kakhulu kwaye ezinobuhlobo nokusingqongileyo ukusuka kumacala omabini e-nickel foil ukuya kwi-substrates ezininzi kwaye sibonise indlela iifilimu zangaphambili nangasemva ezifanelekileyo ngayo kwizicelo ezahlukeneyo.
La macandelo alandelayo axoxa ngobukhulu obahlukeneyo befilimu yegrafiti ngokuxhomekeke kwinani leeleya zegrafini ezihlanganisiweyo: (i) igrafini enye (SLG, ileya e-1), (ii) igrafini ezimbalwa (FLG, < iileya ezili-10), (iii) igrafini eninzi (MLG, iileya ezili-10-30) kunye (iv) ne-NGF (~ iileya ezingama-300). Obu bukhulu bokugqibela buchazwa njengepesenti yendawo (malunga ne-97% yendawo kwi-100 µm2)30. Yiyo loo nto ifilimu yonke ibizwa nje ngokuba yi-NGF.
Iifoyile ze-nickel ze-polycrystalline ezisetyenziselwa ukwenziwa kweefilimu ze-graphene kunye ne-graphite zineempawu ezahlukeneyo ngenxa yokwenziwa kwazo kunye nokucubungula okulandelayo. Kutshanje sibike uphando lokuphucula inkqubo yokukhula kwe-NGF30. Sibonisa ukuba iiparameter zenkqubo ezifana nexesha lokutsalela kunye noxinzelelo lwegumbi ngexesha lesigaba sokukhula zidlala indima ebalulekileyo ekufumaneni ii-NGF zobukhulu obufanayo. Apha, siqhubele phambili ngokukhula kwe-NGF kumphezulu opholisiweyo (FS) kunye nomqolo ongapholishwanga (BS) wefoyile ye-nickel (Umzobo 1a). Iintlobo ezintathu zeesampuli ze-FS kunye ne-BS zihlolwe, zidweliswe kwiTheyibhile 1. Emva kokuhlolwa ngokubonakalayo, ukukhula okufanayo kwe-NGF kumacala omabini efoyile ye-nickel (NiAG) kunokubonwa ngokutshintsha kombala we-bulk Ni substrate ukusuka kwi-metallic grey silver ukuya kumbala ongwevu o-matte (Umzobo 1a); imilinganiselo ye-microscopic iqinisekisiwe (Umzobo 1b, c). I-Raman spectrum eqhelekileyo ye-FS-NGF ebonwe kwindawo ekhanyayo kwaye iboniswe ziintolo ezibomvu, eziluhlaza okwesibhakabhaka kunye ne-orenji kuMfanekiso 1b iboniswe kuMfanekiso 1c. Iincopho zeRaman eziphawulekayo zegraphite G (1683 cm−1) kunye ne-2D (2696 cm−1) ziqinisekisa ukukhula kwe-NGF ekristale kakhulu (Umzobo 1c, Itheyibhile SI1). Kuyo yonke ifilimu, kwabonwa ubukhulu be-Raman spectra enomlinganiselo wobunzulu (I2D/IG) ~0.3, ngelixa ii-Raman spectra ezine-I2D/IG = 0.8 zazingabonakali rhoqo. Ukungabikho kweencopho ezinesiphako (D = 1350 cm-1) kwifilimu yonke kubonisa umgangatho ophezulu wokukhula kwe-NGF. Iziphumo ezifanayo zeRaman zifunyenwe kwisampulu ye-BS-NGF (Umfanekiso SI1 a kunye no-b, Itheyibhile SI1).
Uthelekiso lwe-NiAG FS- kunye ne-BS-NGF: (a) Umfanekiso wesampulu eqhelekileyo ye-NGF (NiAG) ebonisa ukukhula kwe-NGF kwisikali se-wafer (55 cm2) kunye neesampuli ze-BS- kunye ne-FS-Ni eziphumayo, (b) Imifanekiso ye-FS-NGF/Ni efunyenwe nge-microscope ebonakalayo, (c) ii-spectra eziqhelekileyo zeRaman ezirekhodwe kwiindawo ezahlukeneyo kwiphaneli b, (d, f) Imifanekiso ye-SEM kwizikhulisi ezahlukeneyo kwi-FS-NGF/Ni, (e, g) Imifanekiso ye-SEM kwizikhulisi ezahlukeneyo Iiseti ze-BS -NGF/Ni. Utolo oluluhlaza lubonisa ummandla we-FLG, utolo olu-orenji lubonisa ummandla we-MLG (kufutshane nommandla we-FLG), utolo olubomvu lubonisa ummandla we-NGF, kwaye utolo olu-magenta lubonisa ukugoba.
Ekubeni ukukhula kuxhomekeke kubukhulu be-substrate yokuqala, ubungakanani bekristale, ukujongwa, kunye nemida yeenkozo, ukufikelela kulawulo olufanelekileyo lobukhulu be-NGF kwiindawo ezinkulu kusaqhubeka kungumngeni20,34,44. Olu phononongo lusebenzise umxholo esiwupapashe ngaphambili30. Le nkqubo ivelisa ummandla okhanyayo we-0.1 ukuya kwi-3% kwi-100 µm230 nganye. Kula macandelo alandelayo, sibonisa iziphumo kuzo zombini iintlobo zemimandla. Imifanekiso ye-SEM yokukhulisa okuphezulu ibonisa ubukho beendawo ezahlukeneyo ezikhanyayo kumacala omabini (Umzobo 1f, g), ebonisa ubukho beendawo ze-FLG kunye ne-MLG30,45. Oku kuqinisekiswe nangokusasazeka kweRaman (Umzobo 1c) kunye neziphumo ze-TEM (kuxoxwe kamva kwicandelo elithi "FS-NGF: isakhiwo kunye neepropati"). Iindawo ze-FLG kunye ne-MLG ezibonwe kwiisampulu ze-FS- kunye ne-BS-NGF/Ni (i-NGF yangaphambili nangasemva ekhuliswe kwi-Ni) kusenokwenzeka ukuba zikhule kwiinkozo ezinkulu ze-Ni(111) ezenziwe ngexesha lokuqhoboshelwa kwangaphambili22,30,45. Ukugoba kwabonwa kumacala omabini (Umzobo 1b, ubhalwe ngeentolo ezimfusa). Ezi zigoba zihlala zifumaneka kwiifilimu ze-graphene kunye ne-graphite ezikhuliswe kwi-CVD ngenxa yomahluko omkhulu kwi-coefficient of thermal expansion phakathi kwe-graphite kunye ne-nickel substrate30,38.
Umfanekiso we-AFM uqinisekisile ukuba isampulu ye-FS-NGF yayithe tyaba kunesampulu ye-BS-NGF (Umfanekiso SI1) (Umfanekiso SI2). Amaxabiso e-root mean square (RMS) roughness ye-FS-NGF/Ni (Umfanekiso SI2c) kunye ne-BS-NGF/Ni (Umfanekiso SI2d) angama-82 kunye nama-200 nm, ngokulandelanayo (alinganiswe kwindawo engama-20 × 20 μm2). roughness ephezulu inokuqondwa ngokusekelwe kuhlalutyo lomphezulu we-nickel (NiAR) foil kwimeko efunyenweyo (Umfanekiso SI3). Imifanekiso ye-SEM ye-FS kunye ne-BS-NiAR iboniswe kwiMifanekiso SI3a–d, ebonisa iimofologi ezahlukeneyo zomphezulu: i-FS-Ni foil epholisiweyo ine-nano- kunye ne-micron-size particles spherical, ngelixa i-BS-Ni foil engapholishwanga ibonisa ileli yemveliso. njengee-particles ezinamandla aphezulu. kunye nokwehla. Imifanekiso ephantsi nenesisombululo esiphezulu ye-annealed nickel foil (NiA) iboniswe kwiMifanekiso SI3e–h. Kule mifanekiso, sinokubona ubukho beenxalenye ezininzi ze-nickel ezinobukhulu be-micron kumacala omabini e-nickel foil (Umzobo SI3e–h). Iinkozo ezinkulu zinokuba nombono womphezulu we-Ni(111), njengoko bekuxeliwe ngaphambili30,46. Kukho umahluko omkhulu kwimo ye-nickel foil phakathi kwe-FS-NiA kunye ne-BS-NiA. Uburhabaxa obuphezulu be-BS-NGF/Ni bubangelwa ngumphezulu ongapholishwanga we-BS-NiAR, umphezulu wawo uhlala urhabaxa kakhulu nasemva kokutsalwa (Umfanekiso SI3). Olu hlobo lokuchazwa komphezulu ngaphambi kwenkqubo yokukhula luvumela uburhabaxa beefilimu ze-graphene kunye ne-graphite ukuba zilawulwe. Kufuneka kuqatshelwe ukuba i-substrate yokuqala yahlelwa ngokutsha kweenkozo ngexesha lokukhula kwe-graphene, nto leyo eyanciphisa kancinci ubungakanani beenkozo kwaye yandisa uburhabaxa bomphezulu we-substrate xa kuthelekiswa ne-annealed foil kunye ne-catalyst film22.
Ukulungisa uburhabaxa bomphezulu we-substrate, ixesha lokutsalela (ubungakanani bengqolowa)30,47 kunye nolawulo lokukhulula43 kuya kunceda ukunciphisa ukufana kobukhulu be-NGF yengingqi ukuya kwisikali se-µm2 kunye/okanye i-nm2 (oko kukuthi, ukutshintsha kobukhulu be-nanometers ezimbalwa). Ukulawula uburhabaxa bomphezulu we-substrate, iindlela ezifana nokupholisha nge-electrolytic ye-nickel foil ephumayo zinokuqwalaselwa48. I-nickel foil elungisiweyo kwangaphambili ingatsalelwa kubushushu obuphantsi (< 900 °C) 46 kunye nexesha (< 5 min) ukuthintela ukwakheka kweenkozo ezinkulu ze-Ni(111) (eziluncedo ekukhuleni kwe-FLG).
I-SLG kunye ne-FLG graphene azikwazi ukumelana noxinzelelo lomphezulu we-asidi namanzi, zifuna iileya zenkxaso yoomatshini ngexesha leenkqubo zokudlulisa iikhemikhali ezimanzi22,34,38. Ngokungafaniyo nokudluliselwa kweekhemikhali ezimanzi kwe-polymer-supported single-layer graphene38, sifumanise ukuba omabini amacala e-NGF as-grown anokudluliselwa ngaphandle kwenkxaso ye-polymer, njengoko kubonisiwe kuMfanekiso 2a (jonga uMfanekiso SI4a ukuze ufumane iinkcukacha ezithe vetshe). Ukudluliselwa kwe-NGF kwi-substrate ethile kuqala ngokugrumba okumanzi kwefilimu engaphantsi kwe-Ni30.49. Iisampulu ze-NGF/Ni/NGF ezikhulileyo zibekwe ubusuku bonke kwi-15 mL ye-70% HNO3 exutywe ne-600 mL yamanzi a-deionized (DI). Emva kokuba i-Ni foil inyibilike ngokupheleleyo, i-FS-NGF ihlala ithe tyaba kwaye idada phezu komphezulu wolwelo, njengesampulu ye-NGF/Ni/NGF, ngelixa i-BS-NGF intywiliselwa emanzini (Umfanekiso 2a,b). Emva koko i-NGF ehlukanisiweyo yadluliselwa kwibheki enye enamanzi amatsha acocekileyo yaya kwenye ibheki kwaye i-NGF ehlukanisiweyo yahlanjwa kakuhle, iphinda-phinda izihlandlo ezine ukuya kwezintandathu kwisitya seglasi esigobileyo. Ekugqibeleni, i-FS-NGF kunye ne-BS-NGF zabekwa kwisiseko esifunekayo (Umzobo 2c).
Inkqubo yokudlulisa iikhemikhali ezimanzi ezingenayo i-polymer kwi-NGF ekhuliswe kwi-nickel foil: (a) Umzobo wokuhamba kwenkqubo (jonga uMfanekiso SI4 ukuze ufumane iinkcukacha ezithe vetshe), (b) Ifoto yedijithali ye-NGF eyahlulweyo emva kokugrumba kwe-Ni (iisampuli ezi-2), (c) Umzekelo wokudluliselwa kwe-FS - kunye ne-BS-NGF kwi-substrate ye-SiO2/Si, (d) ukudluliselwa kwe-FS-NGF kwi-substrate ye-polymer engacacanga, (e) i-BS-NGF ukusuka kwisampulu efanayo nephaneli d (eyahlulwe yangamacandelo amabini), idluliselwe kwiphepha le-C elifakwe igolide kunye ne-Nafion (i-substrate eguquguqukayo ecacileyo, imiphetho ephawulwe ngeekona ezibomvu).
Qaphela ukuba ukudluliselwa kwe-SLG okwenziwa kusetyenziswa iindlela zokudlulisa iikhemikhali ezimanzi kufuna ixesha elipheleleyo lokucubungula leeyure ezingama-20–24. Ngobuchule bokudlulisa obungena-polymer obuboniswe apha (Umfanekiso SI4a), ixesha lokucubungula ukudluliselwa kwe-NGF lilonke lincitshisiwe kakhulu (malunga neeyure ezili-15). Le nkqubo iqulathe oku: (Inyathelo 1) Lungisa isisombululo sokusika uze ubeke isampuli kuso (~imizuzu eli-10), uze ulinde ubusuku bonke ukusika kwe-Ni (~imizuzu engama-7200), (Inyathelo 2) Hlamba ngamanzi acocekileyo (Inyathelo - 3). Gcina emanzini acocekileyo okanye udlulisele kwi-substrate ekujoliswe kuyo (imizuzu engama-20). Amanzi abanjwe phakathi kwe-NGF kunye ne-bulk matrix asuswa ngesenzo se-capillary (usebenzisa iphepha lokufutha)38, emva koko amaconsi amanzi aseleyo asuswa ngokomiswa kwendalo (malunga nemizuzu engama-30), kwaye ekugqibeleni isampuli yomiswa imizuzu eli-10 kwi-oven ye-vacuum (10–1 mbar) kwi-50–90 °C (imizuzu engama-60)38.
I-Graphite yaziwa ngokumelana nokuba khona kwamanzi nomoya kumaqondo obushushu aphezulu (≥ 200 °C)50,51,52. Sivavanye iisampuli sisebenzisa i-Raman spectroscopy, i-SEM, kunye ne-XRD emva kokugcinwa emanzini axutyiweyo kubushushu begumbi nakwiibhotile ezivaliweyo kangangeentsuku ezimbalwa ukuya kunyaka omnye (Umfanekiso SI4). Akukho kubola okubonakalayo. Umfanekiso 2c ubonisa i-FS-NGF kunye ne-BS-NGF ezizimeleyo emanzini axutyiweyo. Sizibambe kwi-SiO2 (300 nm)/Si substrate, njengoko kubonisiwe ekuqaleni koMfanekiso 2c. Ukongeza, njengoko kubonisiwe kuMfanekiso 2d,e, i-NGF eqhubekayo inokudluliselwa kwiindawo ezahlukeneyo ezifana neepolymers (i-Thermabright polyamide evela kwi-Nexolve kunye ne-Nafion) kunye nephepha lekhabhoni eligqunywe ngegolide. I-FS-NGF edadayo ibekwe lula kwi-substrate ekujoliswe kuyo (Umfanekiso 2c, d). Nangona kunjalo, iisampuli ze-BS-NGF ezinkulu kune-3 cm2 zazinzima ukuziphatha xa zintywiliselwa ngokupheleleyo emanzini. Ngokwesiqhelo, xa ziqala ukuqengqeleka emanzini, ngenxa yokuphathwa ngokungakhathali ngamanye amaxesha ziyaqhekeka zibe ziinxalenye ezimbini okanye ezintathu (Umzobo 2e). Ngokubanzi, sikwazile ukufikelela ekudlulisweni okungenapolymer kwe-PS- kunye ne-BS-NGF (ukudluliselwa okuqhubekayo okungenamthungo ngaphandle kokukhula kwe-NGF/Ni/NGF kwi-6 cm2) kwiisampuli ukuya kuthi ga kwi-6 kunye ne-3 cm2 kwindawo, ngokulandelanayo. Naziphi na iziqwenga ezinkulu okanye ezincinci eziseleyo zinokubonakala (ngokulula kwisisombululo sokugrumba okanye emanzini acocekileyo) kwisiseko esifunekayo (~1 mm2, Umfanekiso SI4b, jonga isampuli edluliselwe kwigridi yobhedu njengakwi-"FS-NGF: Ulwakhiwo kunye neePropati (ezixoxwe ngazo) phantsi kwe-"Ulwakhiwo kunye neePropati") okanye zigcinwe ukuze zisetyenziswe kwixesha elizayo (Umfanekiso SI4). Ngokusekelwe kolu phawu, siqikelela ukuba i-NGF inokufunyanwa ngesivuno esifikelela kwi-98-99% (emva kokukhula kokudluliselwa).
Iisampulu zokudlulisa ngaphandle kwepolymer zihlalutywe ngokweenkcukacha. Iimpawu zokwakheka komphezulu ezifunyenwe kwi-FS- kunye ne-BS-NGF/SiO2/Si (Umzobo 2c) kusetyenziswa i-optical microscopy (OM) kunye nemifanekiso ye-SEM (Umzobo SI5 kunye nomzobo 3) zibonise ukuba ezi sampuli zidluliselwe ngaphandle kwe-microscopy. Umonakalo obonakalayo wesakhiwo njengeemifantu, imingxunya, okanye iindawo ezivulekileyo. Imigoqo kwi-NGF ekhulayo (Umzobo 3b, d, ephawulwe ngeentolo ezimfusa) yahlala ingaguquki emva kokudluliselwa. Zombini ii-FS- kunye ne-BS-NGF zenziwe yimimandla ye-FLG (imimandla ekhanyayo eboniswe ziintolo eziluhlaza okwesibhakabhaka kuMfanekiso 3). Okumangalisayo kukuba, ngokungafaniyo nemimandla embalwa eyonakeleyo edla ngokubonwa ngexesha lokudluliselwa kwe-polymer kweefilimu ze-graphite ezibhityileyo kakhulu, imimandla emininzi ye-FLG kunye ne-MLG enobukhulu be-micron edibanisa ne-NGF (ephawulwe ngeentolo eziluhlaza okwesibhakabhaka kuMfanekiso 3d) idluliselwe ngaphandle kweemifantu okanye ukuqhekeka (Umfanekiso 3d). 3). Ukunyaniseka koomatshini kuqinisekiswe ngakumbi kusetyenziswa imifanekiso ye-TEM kunye ne-SEM ye-NGF edluliselwe kwiigridi zobhedu ze-lace-carbon, njengoko kuxoxwe kamva (“FS-NGF: Ulwakhiwo kunye neePropati”). I-BS-NGF/SiO2/Si edluliselweyo irhabaxa kune-FS-NGF/SiO2/Si enexabiso le-rms eliyi-140 nm kunye ne-17 nm, ngokulandelanayo, njengoko kubonisiwe kuMfanekiso SI6a kunye no-b (20 × 20 μm2). Ixabiso le-RMS le-NGF elidluliselwe kwi-substrate ye-SiO2/Si (RMS < 2 nm) liphantsi kakhulu (malunga namaxesha ama-3) kunele-NGF ekhuliswe kwi-Ni (Umfanekiso SI2), nto leyo ebonisa ukuba uburhabaxa obongezelelweyo bunokuhambelana nomphezulu we-Ni. Ukongeza, imifanekiso ye-AFM eyenziwe kwimiphetho yeesampuli ze-FS- kunye ne-BS-NGF/SiO2/Si ibonise ubukhulu be-NGF obuyi-100 kunye ne-80 nm, ngokulandelanayo (Umfanekiso SI7). Ubukhulu obuncinci be-BS-NGF bunokuba ngumphumo wokuba umphezulu awuvezwanga ngqo kwigesi yangaphambili.
I-NGF edluliselweyo (i-NiAG) ngaphandle kwe-polymer kwi-wafer ye-SiO2/Si (jonga uMfanekiso 2c): (a,b) Imifanekiso ye-SEM ye-FS-NGF edluliselweyo: ukukhulisa okuphantsi nokuphezulu (okuhambelana nesikwere esi-orenji kwiphaneli). Iindawo eziqhelekileyo) – a). (c,d) Imifanekiso ye-SEM ye-BS-NGF edluliselweyo: ukukhulisa okuphantsi nokuphezulu (okuhambelana nendawo eqhelekileyo eboniswe sisikwere esi-orenji kwiphaneli c). (e, f) Imifanekiso ye-AFM ye-FS- kunye ne-BS-NGF ezidluliselweyo. Utolo oluluhlaza okwesibhakabhaka lumele ummandla we-FLG – umahluko oqaqambileyo, utolo lwe-cyan – umahluko omnyama we-MLG, utolo olubomvu – umahluko omnyama umele ummandla we-NGF, utolo olumagenta lumele ukugoba.
Ulwakhiwo lweekhemikhali ze-FS- kunye ne-BS-NGF ezikhulisiweyo nezidluliselweyo luhlalutywe nge-X-ray photoelectron spectroscopy (XPS) (Umzobo 4). Incochoyi ebuthathaka ibonwe kwi-spectra elinganisiweyo (Umzobo 4a, b), ehambelana ne-substrate ye-Ni (850 eV) ye-FS- kunye ne-BS-NGF ezikhulisiweyo (NiAG). Akukho zincochoyi kwi-spectra elinganisiweyo ye-FS- kunye ne-BS-NGF/SiO2/Si (Umzobo 4c; iziphumo ezifanayo ze-BS-NGF/SiO2/Si aziboniswanga), ezibonisa ukuba akukho ngcoliseko ye-Ni eseleyo emva kokudluliselwa. Imifanekiso 4d–f ibonisa i-spectra enesisombululo esiphezulu yamanqanaba e-C1 s, O1 s kunye ne-Si 2p yamandla e-FS-NGF/SiO2/Si. Amandla okubopha e-C1 s ye-graphite yi-284.4 eV53.54. Imilo ethe tyaba yeencopho zegrafiti ngokubanzi ithathwa njengengalinganiyo, njengoko kubonisiwe kuMfanekiso 4d54. I-spectrum ye-core-level C1 s (Umfanekiso 4d) nayo iqinisekisile ukudluliselwa okumsulwa (oko kukuthi, akukho zintsalela zepolymer), okuhambelana nezifundo zangaphambili38. Ububanzi bemigca ye-spectra ye-C1 s yesampulu esandula ukukhuliswa (i-NiAG) kunye nokudluliselwa emva kwayo yi-0.55 kunye ne-0.62 eV, ngokwahlukeneyo. La maxabiso aphezulu kune-SLG (0.49 eV ye-SLG kwi-substrate ye-SiO2)38. Nangona kunjalo, la maxabiso mancinci kunemigca exeliweyo ngaphambili yeesampulu ze-graphene ze-pyrolytic ezijolise kakhulu (~0.75 eV)53,54,55, nto leyo ebonisa ukungabikho kweendawo zekhabhoni ezinesiphako kwizinto ezikhoyo. Ii-spectra ze-C1 s kunye ne-O1 s zomhlaba nazo azinawo amahlombe, zisusa imfuneko yokupheliswa kwe-peak ephezulu54. Kukho incopho yesathelayithi ye-π → π* ejikeleze i-291.1 eV, edla ngokubonwa kwiisampulu zegrafiti. Imiqondiso ye-103 eV kunye ne-532.5 eV kwi-spectra yenqanaba eliphambili le-Si 2p kunye ne-O1 s (jonga uMzobo 4e, f) inxulunyaniswa ne-substrate ye-SiO2 56, ngokwahlukeneyo. I-XPS yindlela ejongene nomphezulu, ngoko ke imiqondiso ehambelana ne-Ni kunye ne-SiO2 efunyenwe ngaphambi nasemva kokudluliselwa kwe-NGF, ngokwahlukeneyo, ithathwa njengevela kummandla we-FLG. Iziphumo ezifanayo zibonwe kwiisampulu ze-BS-NGF ezidluliselweyo (aziboniswanga).
Iziphumo ze-NiAG XPS: (ac) Ukuhlola ii-spectra zezinto ezahlukeneyo ze-elemental atomic ze-FS-NGF/Ni ekhulileyo, i-BS-NGF/Ni kunye ne-FS-NGF/SiO2/Si edluliselweyo, ngokwahlukeneyo. (d–f) Ii-spectra ezinesisombululo esiphezulu zamanqanaba angundoqo C 1 s, O 1s kunye ne-Si 2p yesampulu ye-FS-NGF/SiO2/Si.
Umgangatho uwonke weekristale ze-NGF ezidluliselweyo uhlolwe kusetyenziswa i-X-ray diffraction (XRD). Iipateni ze-XRD eziqhelekileyo (Umzobo SI8) ze-FS- kunye ne-BS-NGF/SiO2/Si ezidluliselweyo zibonisa ubukho beencopho ze-diffraction (0 0 0 2) kunye (0 0 0 4) kwi-26.6° kunye ne-54.7°, efana ne-graphite. . Oku kuqinisekisa umgangatho ophezulu we-crystalline we-NGF kwaye kuhambelana nomgama we-interlayer we-d = 0.335 nm, ogcinwa emva kwenyathelo lokudlulisa. Ubunzulu bencopho ye-diffraction (0 0 0 2) bumalunga namaxesha angama-30 kunencopho ye-diffraction (0 0 0 4), okubonisa ukuba i-NGF crystal plane ihambelana kakuhle nomphezulu wesampuli.
Ngokweziphumo ze-SEM, i-Raman spectroscopy, i-XPS kunye ne-XRD, umgangatho we-BS-NGF/Ni ufunyenwe ufana nowe-FS-NGF/Ni, nangona uburhabaxa bayo be-rms buphezulu kancinci (Imifanekiso SI2, SI5) kunye ne-SI7).
Ii-SLG ezineengqimba zenkxaso yepolymer ukuya kuthi ga kwi-200 nm ubukhulu zinokudada phezu kwamanzi. Olu seto lusetyenziswa rhoqo kwiinkqubo zokudlulisa iikhemikhali ezimanzi ezincediswa yipolymer22,38. I-Graphene kunye ne-graphite azinamanzi (i-engile emanzi 80–90°) 57. Imiphezulu yamandla enokubakho ye-graphene kunye ne-FLG ibikwe ukuba ithe tyaba, kunye namandla anokubakho aphantsi (~1 kJ/mol) kwintshukumo esecaleni yamanzi kumphezulu58. Nangona kunjalo, amandla okusebenzisana abaliweyo kwamanzi kunye ne-graphene kunye neengqimba ezintathu ze-graphene zimalunga ne-−13 kunye ne-−15 kJ/mol,58 ngokulandelelana, nto leyo ebonisa ukuba ukusebenzisana kwamanzi ne-NGF (malunga neengqimba ezingama-300) kuphantsi xa kuthelekiswa ne-graphene. Oku kusenokuba sesinye sezizathu zokuba i-NGF ezimeleyo ihlale ithe tyaba phezu komphezulu wamanzi, ngelixa i-graphene ezimeleyo (edada emanzini) ijika ize iqhekeke. Xa i-NGF intywiliselwa ngokupheleleyo emanzini (iziphumo ziyafana kwi-NGF erhabaxa nethe tyaba), imiphetho yayo iyagoba (Umfanekiso SI4). Kwimeko yokuntywiliselwa ngokupheleleyo, kulindeleke ukuba amandla okusebenzisana kwamanzi ne-NGF aphantse aphindwe kabini (xa kuthelekiswa ne-NGF edadayo) kwaye imiphetho ye-NGF igobe ukuze kugcinwe i-engile ephezulu yoqhagamshelwano (hydrophobicity). Sikholelwa ukuba amaqhinga anokuphuhliswa ukuze kuthintelwe ukugoba kwemiphetho ye-NGF efakwe ngaphakathi. Enye indlela kukusebenzisa izinyibilikisi ezixutyiweyo ukulungisa indlela emanzi ngayo i-graphite film59.
Ukudluliselwa kwe-SLG kwiintlobo ezahlukeneyo ze-substrates ngeenkqubo zokudluliselwa kweekhemikhali ezimanzi kuye kwaxelwa ngaphambili. Ngokwesiqhelo kuyamkelwa ukuba amandla e-van der Waals abuthathaka akhona phakathi kweefilimu ze-graphene/graphite kunye ne-substrates (nokuba zi-substrates eziqinileyo ezifana ne-SiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 kunye ne-lacy carbon films30, 34 okanye i-substrates eziguquguqukayo ezifana ne-polyimide 37). Apha sicinga ukuba ukusebenzisana kohlobo olufanayo kuyaphambili. Asizange sibone monakalo okanye ukuxobuka kwe-NGF kuyo nayiphi na i-substrates evezwe apha ngexesha lokuphathwa koomatshini (ngexesha lokuchazwa phantsi kwe-vacuum kunye/okanye iimeko zomoya okanye ngexesha lokugcina) (umz., Umfanekiso 2, SI7 kunye ne-SI9). Ukongeza, asizange sibone i-SiC peak kwi-XPS C1 s spectrum yenqanaba eliphambili lesampuli ye-NGF/SiO2/Si (Umzobo 4). Ezi ziphumo zibonisa ukuba akukho khonkco leekhemikhali phakathi kwe-NGF kunye ne-substrate ekujoliswe kuyo.
Kwicandelo elingaphambili, “Ukudluliselwa kwe-FS- kunye ne-BS-NGF okungena-polymer,” sibonise ukuba i-NGF inokukhula kwaye idluliselwe kumacala omabini e-nickel foil. Ezi FS-NGF kunye ne-BS-NGF azifani ngokubhekiselele kuburhabaxa bomphezulu, nto leyo eyasishukumisela ukuba sihlolisise ezona zicelo zifanelekileyo kuhlobo ngalunye.
Ukuqwalasela ukucaca kunye nomphezulu ogudileyo we-FS-NGF, sifunde ngeenkcukacha ezithe vetshe ngesakhiwo sayo sendawo, iipropati ze-optical kunye nezombane. Ulwakhiwo kunye nolwakhiwo lwe-FS-NGF ngaphandle kokudluliselwa kwe-polymer lubonakaliswe yi-transmission electron microscopy (TEM) imaging kunye ne-selective area electron diffraction pattern analysis (SAED). Iziphumo ezihambelanayo ziboniswe kuMfanekiso 5. I-low magnification planar TEM imaging ityhile ubukho bemimandla ye-NGF kunye ne-FLG eneempawu ezahlukeneyo ze-electron contrast, oko kukuthi iindawo ezimnyama nezikhanyayo, ngokulandelanayo (Umfanekiso 5a). Ifilimu iyonke ibonisa ukuthembeka okuhle koomatshini kunye nozinzo phakathi kwemimandla eyahlukeneyo ye-NGF kunye ne-FLG, kunye nokugqithana okuhle kwaye akukho monakalo okanye ukukrazuka, okuqinisekiswe yi-SEM (Umfanekiso 3) kunye nezifundo ze-TEM zokukhulisa okuphezulu (Umfanekiso 5c-e). Ngokukodwa, kuMfanekiso 5d ubonisa isakhiwo sebhulorho kwindawo yaso enkulu (indawo ephawulwe ngutolo olumnyama olunamachaphaza kuMfanekiso 5d), olubonakaliswa ngemilo engxantathu kwaye luqulathe umaleko wegraphene onobubanzi obumalunga ne-51. Ulwakhiwo olunesithuba esiphakathi kwe-0.33 ± 0.01 nm luncitshiswa ngakumbi lube ziingqimba ezininzi zegraphene kwindawo encinci (isiphelo sotolo olumnyama oluqinileyo kuMfanekiso 5 d).
Umfanekiso we-Planar TEM wesampulu ye-NiAG engena-polymer kwigridi yobhedu ye-carbon lacy: (a, b) Imifanekiso ye-TEM yokukhulisa ephantsi kuquka imimandla ye-NGF kunye ne-FLG, (ce) Imifanekiso yokukhulisa ephezulu yemimandla eyahlukeneyo kwiphaneli-a kunye nephaneli-b ziintolo eziphawulweyo zombala ofanayo. Iintolo eziluhlaza kwiiphaneli a kunye no-c zibonisa iindawo ezijikelezayo zomonakalo ngexesha lokulungelelaniswa kwemisebe. (f–i) Kwiiphaneli a ukuya ku-c, iipateni ze-SAED kwiindawo ezahlukeneyo ziboniswa ngezangqa eziluhlaza okwesibhakabhaka, i-cyan, i-orenji, kunye nezibomvu, ngokwahlukeneyo.
Ulwakhiwo lweribhoni kuMfanekiso 5c lubonisa (oluphawulwe ngotolo olubomvu) indlela ethe nkqo yeplane yegrafiti lattice, enokubangelwa kukwenziwa kwee-nanofolds ecaleni kwefilimu (inset kuMfanekiso 5c) ngenxa yoxinzelelo olukhulu lwe-shear olungahlawulwanga30,61,62. Phantsi kwe-TEM enesisombululo esiphezulu, ezi nanofolds 30 zibonisa indlela eyahlukileyo yekristale kunezinye iindawo ze-NGF; iiplane zesiseko zegrafiti lattice zijongeka zithe nkqo, endaweni yokuba zijonge ngokuthe tye njengezinye iifilimu (inset kuMfanekiso 5c). Ngokufanayo, ummandla we-FLG ngamanye amaxesha ubonisa iifoldi ezithe nkqo nezimxinwa ezifana nebhendi (eziphawulwe ngeentolo eziluhlaza okwesibhakabhaka), ezibonakala kubukhulu obuphantsi nobuphakathi kwiMifanekiso 5b, 5e, ngokulandelelana. I-inset kuMfanekiso 5e iqinisekisa ukubakho kwee-layers ze-graphene ezimbini nezineeleya ezintathu kwicandelo le-FLG (umgama ophakathi 0.33 ± 0.01 nm), ovumelana kakuhle neziphumo zethu zangaphambili30. Ukongeza, imifanekiso ye-SEM erekhodiweyo ye-NGF engena-polymer edluliselwe kwiigridi zobhedu ngeefilimu ze-lacy carbon (emva kokwenza imilinganiselo ye-TEM ebonakalayo ephezulu) iboniswe kuMfanekiso SI9. Ummandla we-FLG oxhonywe kakuhle (ophawulwe ngotolo oluhlaza okwesibhakabhaka) kunye nommandla oqhekekileyo kuMfanekiso SI9f. Utolo oluhlaza okwesibhakabhaka (emphethweni we-NGF edluliselweyo) luboniswe ngabom ukubonisa ukuba ummandla we-FLG unokumelana nenkqubo yokudluliselwa ngaphandle kwe-polymer. Ngamafutshane, le mifanekiso iqinisekisa ukuba i-NGF exhonywe kancinci (kuquka nommandla we-FLG) igcina ukuthembeka koomatshini nasemva kokuphathwa ngokungqongqo kunye nokuvezwa kwi-vacuum ephezulu ngexesha lokulinganisa kwe-TEM kunye ne-SEM (Umfanekiso SI9).
Ngenxa yokuba tyaba kakhulu kwe-NGF (jonga uMfanekiso 5a), akunzima ukujongisa iiflekhi ecaleni kwe-[0001] domain axis ukuhlalutya isakhiwo se-SAED. Ngokuxhomekeke kubukhulu bendawo yefilimu kunye nendawo ekuyo, iindawo ezininzi ezinomdla (amanqaku ali-12) zichongiwe kwizifundo ze-electron diffraction. KwiMifanekiso 5a–c, ezine kwezi ndawo ziqhelekileyo zibonisiwe kwaye ziphawulwe ngezangqa ezinemibala (eluhlaza okwesibhakabhaka, e-cyan, eorenji, nebomvu ezibhalwe ikhowudi). IMifanekiso 2 kunye no-3 kwimo ye-SAED. IMifanekiso 5f kunye no-g zifunyenwe kummandla we-FLG oboniswe kwiMifanekiso 5 kunye no-5. Njengoko kubonisiwe kwiMifanekiso 5b kunye no-c, ngokulandelelana. Zinesakhiwo esinama-hexagonal esifana ne-graphene ejijekileyo63. Ngokukodwa, uMfanekiso 5f ubonisa iipateni ezintathu ezibekwe ngaphezulu ezine-orientation efanayo ye-[0001] zone axis, ejikelezwe yi-10° kunye ne-20°, njengoko kungqinwa kukungafani kwe-angular kweepere ezintathu ze-(10-10) reflections. Ngokufanayo, uMfanekiso 5g ubonisa iipateni ezimbini ezineehexagonal ezijikeleziswe ngama-20°. Amaqela amabini okanye amathathu eepateni ezineehexagonal kummandla we-FLG anokuvela kwiileya ezintathu ze-graphene ezingaphakathi okanye ezingaphandle kwendiza ezingama-33 ezijikeleziswe ngokumalunga nomnye nomnye. Ngokwahlukileyo koko, iipateni ze-electron diffraction kuMfanekiso 5h,i (ezihambelana nommandla we-NGF oboniswe kuMfanekiso 5a) zibonisa iphethini enye [0001] enobunzulu be-diffraction ephezulu, ehambelana nobukhulu bezinto ezibonakalayo. Ezi modeli ze-SAED zihambelana nesakhiwo se-graphitic esityebileyo kunye nolwalathiso oluphakathi kune-FLG, njengoko kuqikelelwe kwisalathiso 64. Ukuchazwa kweempawu ze-crystalline ze-NGF kutyhile ukubakho kweekristale ezimbini okanye ezintathu ze-graphite (okanye i-graphene) ezibekwe ngaphezulu. Okuphawulekayo ngokukodwa kummandla we-FLG kukuba iikristale zinomlinganiselo othile wokungazinzi kwe-in-plane okanye ngaphandle kwendiza. Iinxalenye zegrafiti/iileya ezinee-engile zokujikeleza ezingaphakathi kweplane ze-17°, 22° kunye ne-25° sele zixeliwe ngaphambili kwi-NGF ekhuliswe kwiifilimu ze-Ni 64. Amaxabiso ee-engile zokujikeleza abonwe kolu phononongo ayahambelana nee-engile zokujikeleza ezibonwe ngaphambili (±1°) ze-graphene ye-BLG63 ejijekileyo.
Iipropati zombane ze-NGF/SiO2/Si zilinganiswe kwi-300 K phezu kwendawo ye-10×3 mm2. Amaxabiso oxinzelelo, ukuhamba kunye nokuqhuba kwe-electron carrier yi-1.6 × 1020 cm-3, 220 cm2 V-1 C-1 kunye ne-2000 S-cm-1, ngokulandelanayo. Amaxabiso okuhamba kunye nokuqhuba kwe-NGF yethu afana ne-graphite2 yendalo kwaye aphezulu kune-graphite ye-pyrolytic esekwe kurhwebo (eveliswe kwi-3000 °C)29. Amaxabiso oxinzelelo lwe-electron carrier abonwayo aphezulu kakhulu kunelawo asandul' ukubikwa (7.25 × 10 cm-3) kwiifilimu ze-graphite ezinobukhulu be-micron ezilungiselelwe kusetyenziswa amaphepha e-polyimide aphezulu (3200 °C) 20.
Sikwasebenzise imilinganiselo yokudluliselwa kwe-UV ebonakalayo kwi-FS-NGF edluliselwe kwi-quartz substrates (Umfanekiso 6). I-spectrum ephumayo ibonisa ukudluliselwa okuphantse kube rhoqo kwe-62% kuluhlu lwe-350–800 nm, nto leyo ebonisa ukuba i-NGF iyakwazi ukukhanya okubonakalayo. Enyanisweni, igama elithi "KAUST" linokubonwa kwifoto yedijithali yesampulu ekuMfanekiso 6b. Nangona isakhiwo se-nanocrystalline se-NGF sahlukile kweso se-SLG, inani leeleya linokuqikelelwa kusetyenziswa umthetho wokulahleka kokudluliselwa kwe-2.3% ngolunye ulwelo65. Ngokwale ntsebenziswano, inani leeleya ze-graphene ezinelahleko yokudluliselwa kwe-38% yi-21. I-NGF ekhulileyo ikakhulu ineeleya ze-graphene ezingama-300, oko kukuthi malunga ne-100 nm ubukhulu (Umfanekiso 1, SI5 kunye ne-SI7). Ke ngoko, sicinga ukuba ukukhanya okubonakalayo okubonakalayo kuhambelana nemimandla ye-FLG kunye ne-MLG, kuba zisasazwa kuyo yonke ifilimu (Imifanekiso 1, 3, 5 kunye ne-6c). Ukongeza kwidatha yesakhiwo engentla, ukuhanjiswa kwamandla kunye nokungafihlisi kuqinisekisa umgangatho ophezulu wekristale we-NGF edluliselweyo.
(a) Umlinganiselo wokudluliselwa kwe-UV obonakalayo, (b) ukudluliselwa kwe-NGF okuqhelekileyo kwi-quartz kusetyenziswa isampuli emeleyo. (c) I-Schematic ye-NGF (ibhokisi emnyama) eneendawo ze-FLG kunye ne-MLG ezisasazwe ngokulinganayo eziphawulwe njengeemilo ezingwevu ezingacwangciswanga kuyo yonke isampuli (jonga uMfanekiso 1) (malunga ne-0.1–3% yendawo kwi-100 μm2). Iimilo ezingacwangciswanga kunye nobukhulu bazo kumzobo zenzelwe ukubonisa kuphela kwaye azihambelani neendawo zokwenyani.
I-NGF ekhanyayo ekhuliswe yi-CVD ngaphambili idluliselwe kwiindawo ze-silicon ezingenanto kwaye isetyenziswa kwiiseli zelanga15,16. Ukusebenza kakuhle kokuguqulwa kwamandla (PCE) okubangelwa yi-1.5%. Ezi NGF zenza imisebenzi emininzi efana nee-compound layers ezisebenzayo, iindlela zokuthutha itshaja, kunye nee-electrodes ezicacileyo15,16. Nangona kunjalo, ifilimu yegrafiti ayifani. Ukulungiswa okungakumbi kuyimfuneko ngokulawula ngononophelo ukumelana neshiti kunye nokudluliselwa kwe-optical kwe-graphite electrode, kuba ezi mpawu zimbini zidlala indima ebalulekileyo ekumiseleni ixabiso le-PCE yeseli yelanga15,16. Ngokwesiqhelo, iifilimu zegrafiti zibonakala nge-97.7% ekukhanyeni okubonakalayo, kodwa zinokumelana neshiti kwe-200–3000 ohms/sq.16. Ukumelana nomphezulu weefilimu zegrafiti kunokuncitshiswa ngokwandisa inani leeleya (ukudluliselwa okuninzi kweeleya zegrafiti) kunye nokufaka i-doping nge-HNO3 (~30 Ohm/sq.)66. Nangona kunjalo, le nkqubo ithatha ixesha elide kwaye iileya ezahlukeneyo zokudlulisa azihlali zigcina unxibelelwano oluhle. Icala lethu elingaphambili le-NGF lineempawu ezifana nokuqhuba umbane kwi-2000 S/cm, ukumelana nephepha lefilimu kwi-50 ohm/sq. kunye nokucaca kwe-62%, okwenza ukuba ibe yindlela efanelekileyo yokuqhuba umbane okanye ii-counter electrodes kwiiseli zelanga15,16.
Nangona ulwakhiwo kunye nekhemistri yomphezulu we-BS-NGF zifana ne-FS-NGF, uburhabaxa bayo bahlukile ("Ukukhula kwe-FS- kunye ne-BS-NGF"). Ngaphambili, besisebenzisa i-graphite yefilimu encinci kakhulu22 njenge-sensor yegesi. Ke ngoko, sivavanye ukuba kunokwenzeka na ukusebenzisa i-BS-NGF kwimisebenzi yokuva igesi (Umfanekiso SI10). Okokuqala, iinxalenye ze-BS-NGF ezinobukhulu be-mm2 zadluliselwa kwi-chip ye-sensor ye-electrode edibanisa idijithali (Umfanekiso SI10a-c). Iinkcukacha zokwenziwa kwe-chip zazixeliwe ngaphambili; indawo yayo esebenzayo yi-9 mm267. Kwimifanekiso ye-SEM (Umfanekiso SI10b kunye no-c), i-electrode yegolide engaphantsi ibonakala ngokucacileyo nge-NGF. Kwakhona, kunokubonwa ukuba ukugubungela i-chip efanayo kufezekisiwe kuzo zonke iisampuli. Ukulinganiswa kwe-sensor yegesi yeegesi ezahlukeneyo kurekhodiwe (Umfanekiso SI10d) (Umfanekiso SI11) kwaye amazinga okuphendula aphumayo aboniswe kwi-Figs. SI10g. Kusenokwenzeka ukuba nezinye iigesi eziphazamisayo kuquka i-SO2 (200 ppm), i-H2 (2%), i-CH4 (200 ppm), i-CO2 (2%), i-H2S (200 ppm) kunye ne-NH3 (200 ppm). Esinye isizathu esinokwenzeka yi-NO2. uhlobo lwe-electrophilic lwegesi22,68. Xa ifunxwa kumphezulu we-graphene, inciphisa ukufunxwa kwangoku kwee-electron yinkqubo. Uthelekiso lwedatha yexesha lokuphendula le-sensor ye-BS-NGF kunye neesensor ezipapashwe ngaphambili luboniswe kwiTheyibhile SI2. Indlela yokuvuselela iisensor ze-NGF kusetyenziswa i-UV plasma, i-O3 plasma okanye unyango lwe-thermal (50–150°C) lweesampuli eziveziweyo iyaqhubeka, ngokufanelekileyo kulandelwe kukusetyenziswa kweenkqubo ezifakwe kwi-69.
Ngexesha lenkqubo ye-CVD, ukukhula kwe-graphene kwenzeka kumacala omabini e-catalyst substrate41. Nangona kunjalo, i-BS-graphene idla ngokukhutshwa ngexesha lenkqubo yokudlulisa41. Kolu phononongo, sibonisa ukuba ukukhula kwe-NGF esemgangathweni ophezulu kunye nokudluliselwa kwe-NGF okungena-polymer kunokufezekiswa kumacala omabini enkxaso ye-catalyst. I-BS-NGF incinci (~80 nm) kune-FS-NGF (~100 nm), kwaye lo mahluko uchazwa yinto yokuba i-BS-Ni ayivezwanga ngokuthe ngqo kwi-precursor gas flow. Sikwafumanise ukuba uburhabaxa be-NiAR substrate buchaphazela uburhabaxa be-NGF. Ezi ziphumo zibonisa ukuba i-FS-NGF ekhulisiweyo ejikelezileyo ingasetyenziswa njengezinto zokuqala ze-graphene (ngendlela yokukhupha i-exfoliation70) okanye njengomjelo oqhubayo kwiiseli zelanga15,16. Ngokwahlukileyo koko, i-BS-NGF iya kusetyenziselwa ukufumanisa igesi (Umzobo SI9) kwaye mhlawumbi kwiinkqubo zokugcina amandla71,72 apho uburhabaxa bayo bomphezulu buya kuba luncedo.
Ukuqwalasela oku kungasentla, kuluncedo ukudibanisa umsebenzi wangoku neefilimu zegrafiti ezipapashwe ngaphambili ezikhuliswe yiCVD kunye nokusebenzisa i-nickel foil. Njengoko kunokubonwa kwiTheyibhile 2, uxinzelelo oluphezulu esilusebenzisileyo lufinyeze ixesha lokuphendula (inqanaba lokukhula) nokuba kumaqondo obushushu aphantsi (aphakathi kwe-850–1300 °C). Sikwafikelele ekukhuleni okukhulu kunesiqhelo, okubonisa ukuba kunokwenzeka ukwanda. Kukho ezinye izinto ekufuneka ziqwalaselwe, ezinye zazo esizifakile kwitheyibhile.
I-NGF ekumgangatho ophezulu enamacala amabini ikhuliswe kwi-nickel foil nge-catalytic CVD. Ngokususa ii-substrates ze-polymer zemveli (ezifana nezo zisetyenziswa kwi-CVD graphene), sifezekisa ukudluliselwa okumanzi kwe-NGF (okukhuliswe ngasemva nangaphambili kwe-nickel foil) kwiindidi ezahlukeneyo ze-process-critical substrates. Okuphawulekayo kukuba, i-NGF ibandakanya imimandla ye-FLG kunye ne-MLG (ngesiqhelo i-0.1% ukuya kwi-3% kwi-100 µm2) edityaniswe kakuhle kwifilimu etyebileyo. I-Planar TEM ibonisa ukuba le mimandla yenziwe ngeenqwaba zee-graphite/graphene particles ezimbini ukuya kwezintathu (iikristale okanye iileya, ngokulandelelana), ezinye zazo zinokungalingani okujikelezayo kwe-10–20°. Imimandla ye-FLG kunye ne-MLG inoxanduva lokucaca kwe-FS-NGF ekukhanyeni okubonakalayo. Ngokuphathelele amaphepha angasemva, anokuthwalwa ngokuhambelana namaphepha angaphambili kwaye, njengoko kubonisiwe, anokuba nenjongo yokusebenza (umzekelo, ekufumaneni igesi). Ezi zifundo ziluncedo kakhulu ekunciphiseni inkunkuma kunye neendleko kwiinkqubo ze-CVD zesikali soshishino.
Ngokubanzi, ubukhulu obuphakathi be-CVD NGF buphakathi kwamaphepha e-graphene (aphantsi kunye namacwecwe amaninzi) kunye namaphepha e-graphite emizi-mveliso (micrometer). Uluhlu lweempawu zawo ezinomdla, kunye nendlela elula esiyiphuhlisileyo yokuvelisa kunye nokuthuthwa kwazo, kwenza ezi filimu zifaneleke ngokukodwa kwizicelo ezifuna impendulo esebenzayo ye-graphite, ngaphandle kweendleko zeenkqubo zemveliso yemizi-mveliso ezisebenzisa amandla amaninzi ezisetyenziswayo ngoku.
Ifoyile ye-nickel enobukhulu obuyi-25 μm (ubumsulwa obuyi-99.5%, Goodfellow) ifakwe kwi-reactor ye-CVD yorhwebo (i-Aixtron 4-intshi BMPro). Inkqubo yacocwa nge-argon yaza yasuswa yaya kuxinzelelo olusisiseko lwe-10-3 mbar. Emva koko ifoyile ye-nickel yafakwa kwi-Ar/H2 (Emva kokuyixuba kwangaphambili ifoyile ye-Ni imizuzu emi-5, ifoyile yavezwa kuxinzelelo lwe-500 mbar kwi-900 °C. I-NGF yafakwa kumanzi e-CH4/H2 (100 cm3 nganye) imizuzu emi-5. Isampuli yapholiswa yaya kubushushu obungaphantsi kwe-700 °C kusetyenziswa i-Ar flow (4000 cm3) kwi-40 °C/min. Iinkcukacha malunga nokuphucula inkqubo yokukhula kwe-NGF zichazwe kwenye indawo30.
Imo yobuso besampulu ibonwe yi-SEM kusetyenziswa imakroskopu yeZeiss Merlin (1 kV, 50 pA). Uburhabaxa bobuso besampulu kunye nobukhulu be-NGF bulinganiswe kusetyenziswa i-AFM (Dimension Icon SPM, Bruker). Ukulinganiswa kwe-TEM kunye ne-SAED kwenziwe kusetyenziswa imakroskopu ye-FEI Titan 80–300 Cubed exhotyiswe ngesibhamu sokukhupha ukukhanya okuphezulu (300 kV), i-monochromator ye-FEI Wien yohlobo kunye ne-CEOS lens spherical aberration corrector ukuze kufunyanwe iziphumo zokugqibela. Isisombululo sendawo esingu-0.09 nm. Iisampulu ze-NGF zidluliselwe kwigridi zekopolo ezigqunywe yi-carbon lacy ukuze kuthathwe imifanekiso ye-TEM ethe tyaba kunye nohlalutyo lwesakhiwo se-SAED. Ke ngoko, uninzi lwee-flocs zesampulu zixhonywe kwiimbobo ze-membrane exhasayo. Iisampulu ze-NGF ezidluliselweyo zihlalutywe yi-XRD. Iipateni ze-diffraction ze-X-ray zifunyenwe kusetyenziswa i-powder diffractometer (iBrucker, i-D2 phase shifter enomthombo weCu Kα, i-1.5418 Å kunye ne-LYNXEYE detector) kusetyenziswa umthombo we-Cu radiation onobubanzi be-beam spot obuyi-3 mm.
Imilinganiselo emininzi yeRaman irekhodwe kusetyenziswa imakroskopu ye-confocal edibeneyo (i-Alpha 300 RA, i-WITeC). Ilaser engama-532 nm enamandla aphantsi okuchukumisa (25%) isetyenzisiwe ukuthintela iziphumo ezibangelwa bubushushu. I-X-ray photoelectron spectroscopy (i-XPS) yenziwe kwi-Kratos Axis Ultra spectrometer phezu kwendawo yesampulu ye-300 × 700 μm2 kusetyenziswa i-monochromatic Al Kα radiation (hν = 1486.6 eV) kumandla e-150 W. I-Resolution spectra ifunyenwe kumandla okudlulisa e-160 eV kunye ne-20 eV, ngokulandelelana. Iisampulu ze-NGF ezidluliselwe kwi-SiO2 zanqunyulwa zaba ziingceba (3 × 10 mm2 nganye) kusetyenziswa i-PLS6MW (1.06 μm) ytterbium fiber laser kwi-30 W. Ii-contacts ze-copper wire (50 μm ubukhulu) zenziwe kusetyenziswa i-silver paste phantsi kwemakroskopu ebonakalayo. Uvavanyo lokuthuthwa kombane kunye neziphumo zeHall lwenziwe kwezi sampuli kwi-300 K kunye notshintsho lwe-magnetic field ye-± 9 Tesla kwinkqubo yokulinganisa iipropati zomzimba (PPMS EverCool-II, Quantum Design, USA). Ii-UV-vis spectra ezidluliselweyo zirekhodwe kusetyenziswa i-Lambda 950 UV-vis spectrophotometer kuluhlu lwe-350-800 nm NGF oludluliselwe kwi-quartz substrates kunye neesampuli zereferensi ye-quartz.
I-chemical resistance sensor (interdigitated electrode chip) yaxhunywa kwibhodi yesekethe eprintiweyo eyenzelwe wena 73 kwaye i-resistance yakhutshwa okwethutyana. Ibhodi yesekethe eprintiweyo apho isixhobo sikhoyo iqhagamshelwe kwiiterminals zoqhagamshelwano kwaye yafakwa ngaphakathi kwigumbi lokuva igesi 74. Ukulinganiswa kwe-resistance kwathathwa kwi-voltage ye-1 V kunye ne-scan eqhubekayo ukusuka ekuhlanjululweni ukuya ekuvezweni kwegesi kwaye emva koko yahlanjululwa kwakhona. Igumbi laqala lacocwa ngokucoca nge-nitrogen kwi-200 cm3 kangangeyure e-1 ukuqinisekisa ukususwa kwazo zonke ezinye ii-analytes ezikhoyo kwigumbi, kuquka nokufuma. Ii-analytes nganye emva koko zakhutshwa kancinci kwigumbi ngesantya esifanayo sokuhamba kwe-200 cm3 ngokuvala isilinda se-N2.
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