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Iifilimu ze-Nanoscale graphite (NGFs) zi-nanomaterials ezinamandla ezinokuveliswa nge-catalytic chemical vapor deposition, kodwa imibuzo ihleli malunga nokukhululeka kwazo kokudluliselwa kunye nendlela i-morphology yomhlaba ekuchaphazela ngayo ukusetyenziswa kwazo kwizixhobo zesizukulwana esilandelayo. Apha sichaza ukukhula kwe-NGF kumacala omabini e-polycrystalline nickel foil (indawo ye-55 cm2, ubukhulu malunga ne-100 nm) kunye nokudluliselwa kwayo kwe-polymer-free (ngaphambili nangasemva, indawo ukuya kwi-6 cm2). Ngenxa ye-morphology ye-catalyst foil, iifilimu ezimbini zekhabhoni ziyahluka kwiimpawu zazo zomzimba kunye nezinye iimpawu (ezifana noburhabaxa bomphezulu). Sibonisa ukuba i-NGFs ene-backside rougher ifaneleke kakuhle ukubhaqwa kwe-NO2, ngelixa i-NGF ilula kwaye iqhube ngakumbi kwicala langaphambili (2000 S / cm, ukuchasana kweshiti - i-50 ohms / m2) ingaba ngabaqhubi abasebenzayo. umjelo okanye i-electrode yeseli yelanga (ekubeni ihambisa i-62% yokukhanya okubonakalayo). Ngokubanzi, ukukhula okuchaziweyo kunye neenkqubo zothutho kunokunceda ukuqonda i-NGF njengenye into yekhabhoni yokusetyenziswa kwezobuchwepheshe apho iifilimu zegraphene kunye ne-micron-thick graphite azifanelekanga.
I-graphite yinto esetyenziswa ngokubanzi kwimizi-mveliso. Ngokucacileyo, igraphite ineempawu zokuxinana kobunzima obuphantsi kunye nomgangatho ophezulu we-thermal kunye ne-electrical conductivity kwinqwelomoya, kwaye izinzile kakhulu kwiindawo ezishushu zobushushu kunye neekhemikhali1,2. I-Flake graphite yinto eyaziwayo yokuqala yophando lwegraphene3. Xa icutshungulwa kwiifilimu ezibhityileyo, inokusetyenziswa kuluhlu olubanzi lwezicelo, kubandakanywa izitshixo zobushushu zezixhobo zombane ezifana nee-smartphones4,5,6,7, njengesixhobo esisebenzayo kwi-sensor8,9,10 kunye nokhuseleko lwe-electromagnetic interference11. I-12 kunye neefilimu ze-lithography kwi-ultraviolet13,14 ngokugqithiseleyo, ukuqhuba iziteshi kwiiseli zelanga15,16. Kuzo zonke ezi zicelo, kuya kuba luncedo olukhulu ukuba iindawo ezinkulu zeefilimu zegraphite (NGFs) ezinobunzima obulawulwa kwi-nanoscale <100 nm zinokuveliswa ngokulula kwaye zihanjiswe.
Iifilimu zegraphite ziveliswa ngeendlela ezahlukeneyo. Kwimeko enye, ukubethelwa kunye nokwandiswa okulandelwa yi-exfoliation kusetyenziswe ukuvelisa i-graphene flakes10,11,17. Iiflakes kufuneka ziphinde zenziwe iifilimu ezinobunzima obufunekayo, kwaye kaninzi kuthatha iintsuku ezininzi ukuvelisa amaphepha ashinyeneyo egraphite. Enye indlela kukuqala nge-graphable solid precursors. Kumashishini, amaphepha eepolymers afakwe i-carbonized (kwi-1000-1500 ° C) kwaye emva koko i-graphitized (kwi-2800-3200 ° C) ukwenza izinto ezicwangcisiweyo ezifanelekileyo. Nangona umgangatho wale filimu uphezulu, ukusetyenziswa kwamandla kubalulekile1,18,19 kwaye ubuncinci bobunzima bukhawulelwe kwii-microns1,18,19,20 ezimbalwa.
I-Catalytic chemical vapor deposition (CVD) yindlela eyaziwayo yokuvelisa iifilimu zegraphene kunye ne-ultrathin graphite (<10 nm) ezinomgangatho ophezulu wesakhiwo kunye neendleko ezifanelekileyo21,22,23,24,25,26,27. Nangona kunjalo, xa kuthelekiswa nokukhula kweefilimu zegraphene kunye ne-ultrathin graphite28, ukukhula kwendawo enkulu kunye / okanye ukusetyenziswa kwe-NGF usebenzisa i-CVD kuphononongwa kancinci11,13,29,30,31,32,33.
Iifilimu zegraphene neegraphite ezikhule kwi-CVD zihlala zifuna ukukhutshelwa kwiisubstrate ezisebenzayo34. Olu tshintsho lwefilimu oluncinci lubandakanya iindlela ezimbini eziphambili35: (1) i-non-etch transfer36,37 kunye (2) i-etch-based based wet chemical transfer (i-substrate ixhaswe)14,34,38. Indlela nganye ineenzuzo kunye nokungonakali kwaye kufuneka ikhethwe ngokuxhomekeke kwisicelo esicetywayo, njengoko kuchaziwe kwenye indawo35,39. Kwiifilimu zegraphene / zegraphite ezikhulile kwii-catalytic substrates, ukudluliselwa ngeenkqubo zekhemikhali ezimanzi (apho i-polymethyl methacrylate (PMMA) iyona ndlela ixhaphakileyo yenkxaso) ihlala iyindlela yokuqala yokukhetha13,30,34,38,40,41,42. Wena et al. Kwakhankanywa ukuba akukho polymer isetyenziselwa ukudluliselwa kwe-NGF (ubungakanani besampuli malunga ne-4 cm2) i-25,43, kodwa akukho nkcukacha ezinikezelweyo malunga nokuzinza kwesampuli kunye / okanye ukuphatha ngexesha lokudluliselwa; Iinkqubo zekhemistri ezimanzi zisebenzisa iipolymers ziquka amanyathelo amaninzi, kubandakanywa nesicelo kunye nokususwa okulandelayo kwe-polymer layer yedini30,38,40,41,42. Le nkqubo inezingeloncedo: umzekelo, iintsalela zepolymer zinokutshintsha iipropati zefilimu ekhulile38. Ukucubungula okongeziweyo kunokususa i-polymer eseleyo, kodwa la manyathelo ongezelelweyo anyusa iindleko kunye nexesha lokuveliswa kwefilimu38,40. Ngethuba lokukhula kwe-CVD, i-layer ye-graphene ayifakwanga kuphela kwicala langaphambili le-catalyst foil (icala elijongene nokuhamba kwe-steam), kodwa nakwi-back side. Nangona kunjalo, le yokugqibela ithathwa njengenkunkuma kwaye inokususwa ngokukhawuleza nge-plasma38,41 ethambileyo. Ukurisayikilisha le filimu kunganceda ukwandisa isivuno, nokuba ikumgangatho ophantsi kunefilimu yekhabhoni yobuso.
Apha, sinikela ingxelo ngolungiselelo lokukhula kwe-wafer-scale bifacial ye-NGF enomgangatho ophezulu wesakhiwo kwi-polycrystalline nickel foil yi-CVD. Kwavavanywa ukuba uburhabaxa bomphambili nasemva kwefoyile buchaphazela njani i-morphology kunye nesakhiwo se-NGF. Sikwabonisa ukudluliselwa kwe-NGF ngendlela engabiziyo kwaye ihambelana nokusingqongileyo ngaphandle kwepolymer ukusuka kumacala omabini e-nickel foil ukuya kwi-substrates esebenzayo kwaye sibonise indlela iifilimu zangaphambili nasemva ezifanelekileyo kwizicelo ezahlukeneyo.
La macandelo alandelayo axoxa ngobunzima befilimu yegraphite eyohlukeneyo ngokuxhomekeke kwinani leeleya zegraphene ezipakishweyo: (i) umaleko omnye wegraphene (SLG, 1 layer), (ii) umaleko omncinci wegraphene (FLG, < 10 layers), (iii) multilayer graphene ( MLG, 10-30 layers) kunye (iv) NGF (~300 layers). Obona bukhulu buqhelekileyo buchazwa njengepesenti yendawo (malunga nama-97% indawo nge-100 µm2)30. Yiyo loo nto yonke ifilimu ibizwa ngokuba yiNGF.
Iifoyile zenickel zePolycrystalline ezisetyenziselwa ukuhlanganiswa kweefilim zegraphene kunye negraphite zinemizobo eyahlukeneyo ngenxa yokwenziwa kwazo kunye nokusetyenzwa kwazo. Kutshanje sixele isifundo sokwandisa inkqubo yokukhula kwe-NGF30. Sibonisa ukuba iiparameters zenkqubo ezifana nexesha lokuqhawula kunye noxinzelelo lwegumbi ngexesha lokukhula lidlala indima ebalulekileyo ekufumaneni i-NGFs yobukhulu obufanayo. Apha, siphinde siphande ngokukhula kwe-NGF kwi-polished front (FS) kunye ne-back unpolish (BS) kwimigangatho ye-nickel foil (Fig. 1a). Iintlobo ezintathu zeesampulu ze-FS kunye ne-BS zihlolwe, ezidweliswe kwiThebhile 1. Ekuhlolweni okubonakalayo, ukukhula okufanayo kwe-NGF kumacala omabini e-nickel foil (NiAG) kunokubonwa ngokuguqulwa kombala we-bulk Ni substrate ukusuka kwisilivere yensimbi. grey kumbala we-matte grey (Umfanekiso 1a); imilinganiselo ye-microscopic yaqinisekiswa (umzobo 1b, c). I-spectrum ye-Raman eqhelekileyo ye-FS-NGF ebonwa kwingingqi eqaqambileyo kwaye iboniswe ngamatolo abomvu, abhlowu kunye ne-orenji kuMzobo 1b uboniswe kuMfanekiso 1c. Iimpawu zeRaman zencopho zegraphite G (1683 cm−1) kunye ne-2D (2696 cm−1) ziqinisekisa ukukhula kwe-NGF ekhazimle kakhulu (Fig. 1c, Table SI1). Kuyo yonke ifilimu, i-predominance ye-Raman spectra kunye ne-intensity ratio (I2D / IG) ~ 0.3 yabonwa, ngelixa i-Raman spectra ene-I2D / IG = 0.8 yayingafane ibonwe. Ukungabikho kweencopho eziphosakeleyo (D = 1350 cm-1) kwifilimu yonke ibonisa umgangatho ophezulu wokukhula kwe-NGF. Iziphumo ezifanayo zeRaman zifunyenwe kwisampuli ye-BS-NGF (Umfanekiso we-SI1 a kunye ne-b, iThebhile SI1).
Ukuthelekiswa kwe-NiAG FS- kunye ne-BS-NGF: (a) Ifoto yesampuli ye-NGF (NiAG) eqhelekileyo ebonisa ukukhula kwe-NGF kwi-wafer scale (55 cm2) kunye neziphumo ze-BS- kunye ne-FS-Ni iisampuli ze-foil, (b) FS-NGF Imifanekiso/ Ni ifunyenwe ngemakroskopu yamehlo, (c) imbonakalo eqhelekileyo yeRaman erekhodiweyo kwizikhundla ezahlukeneyo kwindawo yolawulo b, (d, f) imifanekiso ye-SEM kubukhulu obahlukeneyo kwiFS-NGF/Ni, (e, g) imifanekiso ye-SEM kubukhulu obahlukeneyo Iseta BS -NGF/Ni. Utolo oluluhlaza lubonisa ummandla we-FLG, utolo lwe-orenji lubonisa ummandla we-MLG (kufuphi nommandla we-FLG), utolo olubomvu lubonisa ummandla we-NGF, kwaye utolo lwe-magenta lubonisa ukugoba.
Ekubeni ukukhula kuxhomekeke kubukhulu be-substrate yokuqala, ubungakanani bekristal, ukuqhelaniswa, kunye nemida yengqolowa, ukufezekisa ulawulo olufanelekileyo lwe-NGF ubukhulu kwiindawo ezinkulu kuhlala kungumngeni20,34,44. Olu phononongo lusebenzise umxholo ebesiwupapashe ngaphambili30. Le nkqubo ivelisa ummandla oqaqambileyo we-0.1 ukuya kwi-3% nge-100 µm230. Kula macandelo alandelayo, sinika iziphumo zazo zombini iindidi zemimandla. Imifanekiso ye-SEM yokukhulisa okuphezulu ibonisa ubukho beendawo ezininzi ezikhanyayo ezikhanyayo kumacala omabini (Umfanekiso 1f, g), ebonisa ubukho be-FLG kunye nemimandla ye-MLG30,45. Oku kwaqinisekiswa kwakhona nguRaman osasaza (umzobo 1c) kunye neziphumo ze-TEM (kuxoxwa kamva kwicandelo elithi "FS-NGF: isakhiwo kunye neepropati"). Imimandla ye-FLG kunye ne-MLG ephawulwe kwiisampuli ze-FS- kunye ne-BS-NGF/Ni (i-NGF yangaphambili nasemva ekhulile kwi-Ni) inokuthi ikhule kwiinkozo ezinkulu ze-Ni (111) ezenziwe ngexesha langaphambi kokulinganisa22,30,45. Ukusonga kwabonwa kumacala omabini (umzobo 1b, ophawulwe ngeentolo ezimfusa). Ezi folda zihlala zifumaneka kwi-CVD-ekhulile i-graphene kunye neefilimu ze-graphite ngenxa yokwahlukana okukhulu kwi-coefficient yokwanda kwe-thermal phakathi kwegraphite kunye ne-nickel substrate30,38.
Umfanekiso we-AFM uqinisekisile ukuba isampuli ye-FS-NGF yayilula kunesampula ye-BS-NGF (Umfanekiso we-SI1) (Umfanekiso we-SI2). Ingcambu mean square (RMS) uburhabaxa amaxabiso FS-NGF/Ni (Fig. SI2c) kunye BS-NGF/Ni (Fig. SI2d) are 82 kunye 200 nm, ngokulandelelana (kulinganiswa phezu indawo 20 × 20 μm2). Ubunzima obuphezulu bunokuqondwa ngokusekelwe kuhlalutyo lomphezulu we-nickel (NiAR) foil kwimeko efunyenweyo (Figure SI3). Imifanekiso ye-SEM ye-FS kunye ne-BS-NiAR iboniswe kwiMifanekiso ye-SI3a-d, ebonisa i-morphologies yendawo eyahlukileyo: i-foil ye-FS-Ni epholisiweyo ine-nano- kunye ne-micron-sized spherical particles, ngelixa i-BS-Ni foil engapholisiweyo ibonisa ileli yokuvelisa. njengamasuntswana anamandla aphezulu. kunye nokuncipha. Imifanekiso esezantsi kunye nesisombululo esiphezulu se-nickel foil (i-NiA) iboniswe kwi-Figure SI3e-h. Kula manani, sinokubona ubukho bamaqhekeza e-nickel amaninzi kumacala omabini e-nickel foil (Fig SI3e–h). Iinkozo ezinkulu zinokuba ne-Ni (111) yokuqhelaniswa nomphezulu, njengoko bekuxelwe ngaphambili30,46. Kukho ukungafani okuphawulekayo kwi-nickel foil morphology phakathi kwe-FS-NiA kunye ne-BS-NiA. Uburhabaxa obuphezulu be-BS-NGF/Ni bubangelwa bubume obungaphucukanga be-BS-NiAR, ubuso obuhlala buba rhabaxa kakhulu nangemva kokuba kufakwe i-annealing (Figure SI3). Olu hlobo lophawu lomphezulu phambi kwenkqubo yokukhula luvumela uburhabaxa bemifanekiso bhanyabhanya yegraphene negraphite ukuba ilawulwe. Kufuneka kuqatshelwe ukuba i-substrate yokuqala iphinde yahlengahlengiswa ngexesha lokukhula kwegraphene, ethe yanciphisa kancinane ubungakanani beenkozo kwaye yathi yanyusa uburhabaxa bomphezulu we-substrate xa kuthelekiswa nefoyile efakwe i-anneal kunye ne-catalyst film22.
Ukulungisa kakuhle uburhabaxa bomphezulu we-substrate, ixesha lokufakwa (ubungakanani beenkozo)30,47 kunye nolawulo lokukhulula43 kuya kunceda ukunciphisa ukufana kobukhulu be-NGF yengingqi ukuya kwisikali se-µm2 kunye/okanye nkqu nm2 (okt, ukuguquguquka kobuninzi bee-nanometers ezimbalwa). Ukulawula uburhabaxa bomphezulu we-substrate, iindlela ezifana ne-electrolytic polishing ye-foil ye-nickel enesiphumo zingaqwalaselwa48. I-foil ye-nickel efakwe ngaphambili inokuthi ifakwe kwiqondo lokushisa eliphantsi (< 900 ° C) 46 kunye nexesha (< 5 min) ukuphepha ukubunjwa kweenkozo ezinkulu ze-Ni (111) (eziluncedo ekukhuleni kwe-FLG).
I-SLG kunye ne-FLG i-graphene ayikwazi ukujamelana nokunyanzeliswa komphezulu we-acids kunye namanzi, ifuna iileya zenkxaso yomatshini ngexesha leenkqubo zokudlulisa iikhemikhali ezimanzi22,34,38. Ngokuchasene nokugqithiswa kweekhemikhali ezimanzi ze-polymer-ixhaswe ngumgangatho owodwa we-graphene38, sifumene ukuba macala omabini e-NGF ekhulileyo anokudluliselwa ngaphandle kokuxhaswa kwe-polymer, njengoko kuboniswe kuMfanekiso 2a (jonga umfanekiso we-SI4a ngolwazi olungakumbi). Ukuhanjiswa kwe-NGF kwi-substrate enikiweyo kuqala ngokufakwa okumanzi kwefilimu ephantsi ye-Ni30.49. Iisampulu ezikhulisiweyo ze-NGF/Ni/NGF zafakwa ngobusuku kwi-15 mL ye-70% ye-HNO3 exutywe nge-600 mL yamanzi enziwe i-deionized (DI). Emva kokuba i-Ni foil ichithwe ngokupheleleyo, i-FS-NGF ihlala ithe tyaba kwaye idada phezu kolwelo, njengesampulu ye-NGF/Ni/NGF, ngelixa i-BS-NGF intywiliselwa emanzini (Fig. 2a,b). I-NGF ekwanti iye yafuduswa isuka kwenye ibhekile enamanzi amatsha adiyiniweyo yasiwa kwenye ibhekile kwaye i-NGF ekwanti yahlanjwa ngocoselelo, iphinda-phinda kane ukuya kwezintandathu ngesitya seglasi esiconcave. Ekugqibeleni, i-FS-NGF kunye ne-BS-NGF zifakwe kwi-substrate efunwayo (Umfanekiso 2c).
Inkqubo yokudlulisa imichiza emanzi yePolymer-free ye-NGF ekhuliswe kwi-nickel foil: (a) Idayagram yokuhambahamba kwenkqubo (jonga uMfanekiso SI4 ngeenkcukacha ezithe vetshe), (b) Ifoto yeDijithali ye-NGF eyahluliweyo emva kwe-Ni etching (iisampulu ezi-2), (c) Umzekelo FS - kunye nokudluliselwa kwe-BS-NGF kwi-SiO2 / Si substrate, (d) i-FS-NGF yokudluliselwa kwi-polymer substrate e-opaque, (e) i-BS-NGF esuka kwisampuli efanayo njengephaneli d (yahlulwe ngamacandelo amabini), idluliselwe kwiphepha le-C legolide. kunye neNafion (i-flexible transparent substrate, imiphetho ephawulwe ngeekona ezibomvu).
Qaphela ukuba ukuhanjiswa kwe-SLG okwenziwa kusetyenziswa iindlela zokudlulisa iikhemikhali ezimanzi zifuna ixesha elipheleleyo le-20-24 iiyure ze-38. Ngobuchule bokudlulisa obungenapolymer buboniswe apha (Umfanekiso SI4a), ixesha elipheleleyo lokudlulisa i-NGF liyancipha kakhulu (malunga neeyure ze-15). Inkqubo iquka: (Inyathelo 1) Lungiselela isisombululo se-etching kwaye ubeke isampuli kuyo (~ imizuzu eyi-10), uze ulinde ubusuku bonke kwi-Ni etching (~ 7200 imizuzu), (Isinyathelo 2) Hlanza ngamanzi adibeneyo (Isinyathelo-3) . gcina kumanzi adibeneyo okanye udlulisele kwi-substrate ekujoliswe kuyo (i-20 min). Amanzi abanjwe phakathi kwe-NGF kunye ne-matrix ye-bulk isuswa yi-capillary action (usebenzisa i-blotting paper) i-38, emva koko amaconsi asele asele asuswe ngokumisa kwendalo (malunga ne-30 min), kwaye ekugqibeleni isampuli yomiswa nge-10 min. imizuzu kwi-oven yokucoca (10-1 mbar) kwi-50-90 ° C (imizuzu engama-60) i-38.
Igraphite iyaziwa ukumelana nobukho bamanzi kunye nomoya kumaqondo obushushu aphezulu ngokufanelekileyo (≥ 200 °C)50,51,52. Sivavanye iisampulu sisebenzisa i-Raman spectroscopy, i-SEM, kunye ne-XRD emva kokugcinwa kumanzi ahlanjululweyo kwindawo yobushushu begumbi kunye nakwiibhotile ezivaliweyo naphi na ukusuka kwiintsuku ezimbalwa ukuya kunyaka omnye (Umfanekiso SI4). Akukho ukuthotywa okubonakalayo. Umzobo we-2c ubonisa i-FS-NGF ekhululekile kunye ne-BS-NGF emanzini adibeneyo. Sazithatha kwi-SiO2 (300 nm) / Si substrate, njengoko kuboniswe ekuqaleni koMfanekiso 2c. Ukongezelela, njengoko kuboniswe kwi-Figure 2d, e, i-NGF eqhubekayo inokudluliselwa kwii-substrates ezahlukeneyo ezifana ne-polymers (i-Thermabright polyamide esuka kwi-Nexolve ne-Nafion) kunye nephepha lekhabhoni elifakwe ngegolide. I-FS-NGF edadayo yayibekwe ngokulula kwi-substrate ekujoliswe kuyo (Umfanekiso 2c, d). Nangona kunjalo, iisampuli ze-BS-NGF ezinkulu kune-3 cm2 kwakunzima ukuphatha xa zintywiliselwa ngokupheleleyo emanzini. Ngokuqhelekileyo, xa beqala ukuqengqeleka emanzini, ngenxa yokuphathwa ngokungakhathali ngamanye amaxesha baqhekeza kwiindawo ezimbini okanye ezintathu (Umfanekiso 2e). Ngokubanzi, sakwazi ukufezekisa ukudluliselwa kwe-polymer-free ye-PS- kunye ne-BS-NGF (ukudluliselwa ngokuqhubekayo ngaphandle kwe-NGF / Ni / NGF ukukhula kwi-6 cm2) kwiisampuli ukuya kwi-6 kunye ne-3 cm2 kwindawo, ngokulandelanayo. Nawaphi na amaqhekeza amakhulu okanye amancinci aseleyo anokuba (abonwa ngokulula kwisisombululo sokutsala okanye amanzi adityanisiweyo) kwi-substrate efunwayo (~1 mm2, Figure SI4b, bona isampulu ekhutshelwe kwigridi yobhedu njengaku “FS-NGF: Ulwakhiwo kunye neePropati (kuxoxiwe) phantsi kwe "Structure and Properties") okanye ukugcina ukusetyenziswa kwixesha elizayo (Figure SI4). Ngokusekelwe kulo mqathango, siqikelela ukuba i-NGF inokubuyiselwa kwimveliso ukuya kwi-98-99% (emva kokukhula kokudluliselwa).
Iisampuli zokutshintshela ngaphandle kwepolymer zihlalutywe ngokweenkcukacha. Iimpawu ze-Surface morphological ezifunyenwe kwi-FS- kunye ne-BS-NGF / SiO2 / Si (Umfanekiso 2c) usebenzisa i-microscopy ye-optical (OM) kunye nemifanekiso ye-SEM (Umfanekiso we-SI5 kunye ne-Fig. 3) ibonise ukuba ezi sampuli zidluliselwe ngaphandle kwe-microscopy. Umonakalo wesakhiwo obonakalayo njengeentanda, imingxuma, okanye iindawo ezivuliweyo. Iifolthi kwi-NGF ekhulayo (umzobo 3b, d, ophawulwe ngeentolo ezimfusa) zahlala ziqinile emva kokudluliselwa. Zomibini i-FS- kunye ne-BS-NGF zenziwe ngemimandla ye-FLG (imimandla eqaqambileyo eboniswe ngeentolo eziluhlaza kuMfanekiso 3). Okumangalisayo kukuba, ngokungafaniyo nemimandla embalwa eyonakeleyo ebonwa ngokuqhelekileyo ngexesha lokudluliselwa kwepolymer yeefilimu ze-ultrathin graphite, imimandla emininzi ye-FLG kunye ne-MLG edibanisa kwi-NGF (ephawulwe ngeentolo eziluhlaza kuMzobo 3d) zidluliselwe ngaphandle kokuqhekeka okanye ukuphuka (Umfanekiso 3d) . 3). . Ukuthembeka koomatshini kwaqinisekiswa ngakumbi kusetyenziswa imifanekiso ye-TEM kunye ne-SEM ye-NGF ekhutshelwe kwiigridi zobhedu ze-lace-carbon, njengoko kuxoxwe ngazo kamva ("FS-NGF: Ulwakhiwo kunye neePropati"). I-BS-NGF/SiO2/Si egqithiselweyo irhabaxa kuneFS-NGF/SiO2/Si enamaxabiso e-rms ye-140 nm kunye ne-17 nm, ngokulandelanayo, njengoko kubonisiwe kuMfanekiso SI6a kunye ne-b (20 × 20 μm2). Ixabiso le-RMS le-NGF elidluliselwe kwi-substrate ye-SiO2 / Si (RMS <2 nm) iphantsi kakhulu (malunga namaxesha e-3) kunokuba i-NGF ikhule kwi-Ni (Figure SI2), ebonisa ukuba i-roughness eyongezelelweyo inokuhambelana ne-Ni surface. Ukongezelela, imifanekiso ye-AFM eyenziwa kumaphethelo e-FS- kunye ne-BS-NGF / SiO2 / Si iisampuli zibonisa ubukhulu be-NGF be-100 kunye ne-80 nm, ngokulandelanayo (umzobo SI7). Ubuncinci obuncinci be-BS-NGF bunokuba ngumphumo wokuba umphezulu ungabonakali ngokuthe ngqo kwigesi yangaphambili.
I-NGF edlulisiweyo (i-NiAG) ngaphandle kwe-polymer kwi-SiO2 / i-Si wafer (jonga uMzobo 2c): (a,b) Imifanekiso ye-SEM yokudluliselwa kwe-FS-NGF: ukukhulisa okuphantsi kunye okuphezulu (okuhambelana nesikwere se-orenji kwiphaneli). Iindawo eziqhelekileyo) – a). (c, d) Imifanekiso ye-SEM yokudluliselwa kwe-BS-NGF: ukukhulisa okuphantsi kunye nokuphakama okuphezulu (okuhambelana nommandla oqhelekileyo oboniswe kwisikwere se-orange kwipaneli c). (e, f) Imifanekiso ye-AFM yee-FS ezidluliselweyo kunye ne-BS-NGFs. Utolo oluluhlaza lumele ummandla we-FLG - umahluko oqaqambileyo, utolo lwecyan - umahluko omnyama we-MLG, utolo olubomvu - umahluko omnyama umele ummandla we-NGF, utolo lwe-magenta lumele ugobe.
Ukubunjwa kweekhemikhali ze-FS ezikhulile kwaye zidluliselwe kunye ne-BS-NGF zahlaziywa nge-X-ray photoelectron spectroscopy (XPS) (umzobo 4). I-peak ebuthakathaka yabonwa kwi-spectra elinganisiweyo (Umfanekiso 4a, b), ehambelana ne-Ni substrate (850 eV) ye-FS ekhulile kunye ne-BS-NGFs (NiAG). Akukho zincopho kwi-spectra elinganisiweyo yokudluliselwa kwe-FS- kunye ne-BS-NGF / SiO2 / Si (Umfanekiso 4c; iziphumo ezifanayo ze-BS-NGF / SiO2 / Si aziboniswa), ebonisa ukuba akukho ntsalela ye-Ni yokungcoliswa emva kokudluliselwa. . Amanani e-4d-f abonisa i-spectra ephezulu ye-C 1 s, i-O 1 s kunye ne-Si 2p yamandla e-FS-NGF / SiO2 / Si. Amandla okubopha i-C 1 s yegraphite yi-284.4 eV53.54. Imilo yomgca yeencopho zegraphite ngokuqhelekileyo ithathwa njenge-asymmetrical, njengoko kubonisiwe kuMfanekiso 4d54. I-high-resolution core-level C 1 s spectrum (Fig. 4d) iphinde iqinisekise ukuhanjiswa okucocekileyo (okt, akukho zintsalela ze-polymer), ezihambelana nezifundo zangaphambili38. I-linewidths ye-C 1 s spectra yesampuli esanda kukhula (NiAG) kwaye emva kokudluliselwa yi-0.55 kunye ne-0.62 eV, ngokulandelanayo. La maxabiso aphezulu kunalawo e-SLG (0.49 eV ye-SLG kwi-SiO2 substrate)38. Nangona kunjalo, la maxabiso mancinci kunobubanzi bomgca obuxeliweyo ngaphambili kwiisampulu ze-pyrolytic graphene ezijolise kakhulu (~ 0.75 eV) 53,54,55, ebonisa ukungabikho kweziza zekhabhoni ezineziphene kwizinto zangoku. I-C 1 kunye ne-O 1 yomgangatho we-spectra womgangatho womhlaba nawo akanawo amagxa, ukuphelisa imfuno ye-high-resolution peak deconvolution54. Kukho i-π → π* incopho yesathelayithi ejikeleze i-291.1 eV, ehlala ibonwa kwiisampulu zegraphite. Iimpawu ze-103 eV kunye ne-532.5 eV kwi-Si 2p kunye ne-O 1 s core level spectra (bona i-Fig. 4e, f) ibangelwa kwi-substrate ye-SiO2 56, ngokulandelanayo. I-XPS yinkqubo ejongene nomphezulu, ngoko ke iimpawu ezihambelana ne-Ni kunye ne-SiO2 zifunyenwe ngaphambi nangemva kokudluliselwa kwe-NGF, ngokulandelanayo, kucingelwa ukuba zivela kummandla we-FLG. Iziphumo ezifanayo ziye zajongwa kwiisampuli ezidlulisiweyo ze-BS-NGF (ezingaboniswa).
Iziphumo ze-NiAG XPS: (ac) Uvavanyo lwespektha yokwakheka kweathom eyahluka-hlukeneyo ye-FS-NGF/Ni, BS-NGF/Ni kwaye idluliselwe FS-NGF/SiO2/Si, ngokulandelelanayo. (d–f) I-spectra ye-high-resolution yamanqanaba angundoqo e-C 1 s, i-O 1 kunye ne-Si 2p ye-FS-NGF/SiO2/Si isampuli.
Umgangatho opheleleyo weekristali ze-NGF ezidluliselweyo zavavanywa kusetyenziswa i-X-ray diffraction (XRD). Iipateni eziqhelekileyo ze-XRD (Umfanekiso we-SI8) we-FS- kunye ne-BS-NGF / SiO2 / Si ebonisa ubukho be-diffraction peaks (0 0 0 2) kunye (0 0 0 4) kwi-26.6 ° kunye ne-54.7 °, efana negraphite. . Oku kuqinisekisa umgangatho ophezulu we-crystalline we-NGF kwaye uhambelana nomgama we-interlayer we-d = 0.335 nm, ogcinwa emva kwesinyathelo sokudlulisa. Ubuninzi bencopho ye-diffraction (0 0 0 2) malunga namaxesha angama-30 encopho ye-diffraction (0 0 0 4), ebonisa ukuba indiza ye-crystal ye-NGF ihambelana kakuhle nesampuli yomhlaba.
Ngokweziphumo ze-SEM, i-Raman spectroscopy, i-XPS kunye ne-XRD, umgangatho we-BS-NGF / Ni wafunyanwa ufana ne-FS-NGF / Ni, nangona i-rms roughness yayo yayiphezulu kancinane (Amanani SI2, SI5) kunye ne-SI7).
Ii-SLG ezineeleya zepolymer zokuxhasa ukuya kuthi ga kwi-200 nm ubukhulu zinokudada emanzini. Olu cwangciso lusetyenziswa ngokuqhelekileyo kwiinkqubo ze-polymer-assisted wet chemical transfer22,38. Igraphene kunye negraphite ziyi-hydrophobic (i-angle emanzi 80-90 °) 57. Imiphezulu yamandla enokubakho kuzo zombini igraphene kunye neFLG kuxelwe ukuba ithe tyaba, inamandla asezantsi anokwenzeka (~1 kJ/mol) ukwenzela intshukumo esecaleni yamanzi kumphezulu58. Nangona kunjalo, amandla okusebenzisana okubaliweyo kwamanzi kunye negraphene kunye neengqimba ezintathu zegraphene zimalunga - 13 kunye - 15 kJ / mol,58 ngokulandelanayo, ebonisa ukuba ukusebenzisana kwamanzi ne-NGF (malunga ne-300 layers) kuphantsi xa kuthelekiswa negraphene. Oku kunokuba sesinye sezizathu zokuba i-NGF ekhululekileyo ihlala ithe tyaba phezu kwamanzi, ngelixa i-graphene ekhululekile (edada emanzini) ijika kwaye yophuka. Xa i-NGF intywiliselwa ngokupheleleyo emanzini (iziphumo ziyafana kwi-NGF erhabaxa kunye necaba), imiphetho yayo iyagoba (Figure SI4). Kwimeko yokucwiliswa okupheleleyo, kulindeleke ukuba i-NGF-amandla okusebenzisana kwamanzi aphantse aphindwe kabini (xa kuthelekiswa ne-NGF edadayo) kwaye imida ye-NGF fold ukugcina i-angle ephezulu yoqhagamshelwano (i-hydrophobicity). Sikholelwa ukuba amaqhinga anokuphuhliswa ukuphepha ukugoba imida yee-NGF ezizinzisiweyo. Enye indlela kukusebenzisa izinyibilikisi ezixubeneyo ukulungisa ukusabela kokumanzi kwefilim59.
Ukudluliselwa kwe-SLG kwiintlobo ezahlukeneyo ze-substrates ngokusebenzisa iinkqubo ezimanzi zokudluliselwa kweekhemikhali kuye kwaxelwa ngaphambili. Kuyamkelwa ngokubanzi ukuba amandla abuthathaka e-van der Waals akhona phakathi kwemifanekiso bhanyabhanya yegraphene/graphite kunye ne substrates (makube ziisubstrates eziqinileyo ezifana neSiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 kunye nelacy carbon films30, 34 okanye substrates eziguquguqukayo. ezifana polyimide 37). Apha sicinga ukuba intsebenziswano yohlobo olufanayo yongamele. Asizange siqaphele nawuphi na umonakalo okanye ukuxothwa kwe-NGF kuyo nayiphi na i-substrates evezwe apha ngexesha lokuphatha ngomatshini (ngexesha lokubonakaliswa kweempawu phantsi kwe-vacuum kunye / okanye iimeko ze-atmospheric okanye ngexesha lokugcinwa) (umz., Umfanekiso 2, SI7 kunye ne-SI9). Ukongezelela, asizange sigcine i-SiC i-peak kwi-spectrum ye-XPS C 1 yenqanaba eliphambili lesampula ye-NGF / SiO2 / Si (umzobo 4). Ezi ziphumo zibonisa ukuba akukho bhondi yeekhemikhali phakathi kwe-NGF kunye ne-substrate ekujoliswe kuyo.
Kwicandelo langaphambili, "Ukudluliselwa kwe-Polymer-free ye-FS- kunye ne-BS-NGF," sibonise ukuba i-NGF inokukhula kwaye idlulisele kumacala omabini e-nickel foil. Ezi FS-NGFs kunye ne-BS-NGF azifani ngokumalunga noburhabaxa bomphezulu, okwenze ukuba sihlolisise ezona zicelo zifanelekileyo kuhlobo ngalunye.
Ukuqwalasela ukungafihli kunye nomgangatho ogudileyo we-FS-NGF, sifunde isakhiwo sayo sendawo, iimpawu zombane kunye neempawu zombane ngokubanzi. Ubume kunye nesakhiwo se-FS-NGF ngaphandle kokudluliselwa kwepolymer zibonakaliswe ngokugqithiswa kwe-electron microscopy (TEM) imaging kunye neendawo ezikhethiweyo ze-electron diffraction (SAED) uhlalutyo lwepatheni. Iziphumo ezihambelanayo ziboniswa kuMzobo 5. I-imaging ye-TEM yokukhulisa okuphantsi ibonise ubukho bemimandla ye-NGF kunye ne-FLG eneempawu ezahlukeneyo ze-electron, oko kukuthi iindawo ezimnyama kunye nezikhanyayo, ngokulandelanayo (umzobo 5a). Ifilimu iyonke ibonisa ukunyaniseka komatshini kunye nokuzinza phakathi kwemimandla eyahlukeneyo ye-NGF kunye ne-FLG, kunye nokugqithisa okulungileyo kwaye akukho monakalo okanye ukukrazula, okuye kwaqinisekiswa kwakhona yi-SEM (Umfanekiso 3) kunye nezifundo eziphezulu zeTEM (Figure 5c-e). Ngokukodwa, kwi-Fig. Umfanekiso we-5d ubonisa isakhiwo sebhulorho kwindawo yayo enkulu (indawo ephawulwe ngotolo olumnyama olunomgca we-Figure 5d), obonakaliswe ngunxantathu we-triangular kwaye iqulethe i-graphene layer kunye nobubanzi obumalunga ne-51. Ukwakheka kunye nesithuba phakathi kweplanar eyi-0.33 ± 0.01 nm kuye kuncitshiswe ngakumbi ukuya kwiileya ezininzi zegraphene kwezona ndawo zimxinwa (isiphelo sotolo olumnyama oluqinileyo kuMfanekiso 5 d).
Umfanekiso wePlanar weTEM wesampulu ye-NiAG engenapolymer kwigridi yobhedu ye-carbon lacy: (a, b) Imifanekiso ye-TEM yokukhulisa okuphantsi kuquka imimandla ye-NGF kunye ne-FLG, (ce) Imifanekiso yolwaliso oluphezulu lwemimandla eyahlukeneyo kwiphaneli-a kunye nephaneli-b i iintolo eziphawulweyo zombala ofanayo. Iintolo eziluhlaza kwiipaneli a kunye no-c zibonisa iindawo ezijikelezayo zomonakalo ngexesha lokulungelelaniswa kwe-beam. (f–i) Kwiiphaneli ukusuka ku-a ukuya ku-c, iipateni ze-SAED kwimimandla eyahlukeneyo ziboniswa ngezangqa eziblowu, ezi-cyan, eziorenji, nezibomvu ngokulandelelanayo.
Isakhiwo seribhoni kwi-Figure 5c sibonisa (ephawulwe ngotolo olubomvu) ukuqhelaniswa ngokuthe nkqo kweeplani ze-graphite lattice, ezinokuthi zibe ngenxa yokubunjwa kwe-nanofolds ecaleni kwefilimu (ifakwe kuMfanekiso 5c) ngenxa yoxinzelelo lwe-shear olugqithisileyo30,61,62 . Ngaphantsi kwe-TEM ephezulu, ezi nanofolds ze-30 zibonisa i-crystallographic orientation eyahlukileyo kunommandla we-NGF; iinqwelomoya zesiseko selattice yegraphite zijongwe phantse ngokuthe nkqo, kunokuba ngokuthe tye njengefilimu yonke (ifakwe kuMfanekiso 5c). Ngokufanayo, ummandla we-FLG ngamanye amaxesha ubonisa ukugoba okufana nomgca kunye nokumxinwa okufana nebhendi (ephawulwe ngeentolo eziluhlaza), ezibonakala ngokukhuliswa okuphantsi nokuphakathi kwiMifanekiso 5b, 5e, ngokulandelelanayo. I-inset kwi-Figure 5e iqinisekisa ubukho bee-graphene layers ezimbini kunye nezintathu kwicandelo le-FLG (umgama we-interplanar 0.33 ± 0.01 nm), ehambelana kakuhle neziphumo zethu zangaphambili30. Ukongezelela, imifanekiso ye-SEM erekhodiweyo ye-NGF ye-polymer-free idluliselwe kwiigridi zobhedu kunye neefilimu zekhabhoni ze-lacy (emva kokwenza imilinganiselo ye-TEM yokujonga phezulu) iboniswe kwi-Figure SI9. Ummandla weFLG omiswe kakuhle (ophawulwe ngotolo oluhlaza) kunye nommandla owaphukileyo kuMfanekiso SI9f. Utolo oluluhlaza okwesibhakabhaka (ekugqibeleni kwe-NGF edluliselweyo) ibonakaliswe ngenjongo ukubonisa ukuba ummandla we-FLG unokuxhathisa inkqubo yokudlulisa ngaphandle kwepolymer. Isishwankathelo, le mifanekiso iqinisekisa ukuba i-NGF emiswe ngokuyinxenye (kubandakanywa nommandla we-FLG) igcina ingqibelelo yomatshini nasemva kokuphathwa ngokungqongqo kunye nokuvezwa kwi-vacuum ephezulu ngexesha le-TEM kunye nemilinganiselo ye-SEM (Umfanekiso SI9).
Ngenxa yokugqwesa okugqwesileyo kwe-NGF (jonga uMzobo 5a), akunzima ukuqhelanisa ama-flakes kunye ne-domain axis ye- [0001] ukuhlalutya isakhiwo se-SAED. Ngokuxhomekeke kubukhulu bendawo yefilimu kunye nendawo yayo, imimandla emininzi enomdla (i-12 amaphuzu) ichongiwe kwizifundo ze-electron diffraction. Kwimizobo 5a–c, emine kule mimandla iqhelekileyo ibonisiwe kwaye imakishwe ngezangqa ezinemibala (blue, cyan, orenji, kunye nekhowudi ebomvu). Amanani 2 kunye ne-3 kwimodi ye-SAED. Amanani e-5f kunye ne-g afunyenwe kummandla we-FLG oboniswe kwiMifanekiso ye-5 kunye ne-5. Njengoko kuboniswe kwiMifanekiso 5b kunye no-c, ngokulandelanayo. Zinesakhiwo esine-hexagonal sifana negraphene63 ejijekileyo. Ngokukodwa, i-Figure 5f ibonisa iipateni ezintathu ezibekwe phezulu kunye nokuqhelaniswa okufanayo kwe- [0001] ye-axis yendawo, ejikelezwe yi-10 ° kunye ne-20 °, njengoko kubonakaliswe ukungahambi kakuhle kwe-angular yeeperi ezintathu ze-reflections (10-10). Ngokufanayo, i-Figure 5g ibonisa iipateni ezimbini eziphakamileyo ze-hexagonal ezijikelezwe ngama-20 °. Amaqela amabini okanye amathathu eepateni ze-hexagonal kwingingqi ye-FLG inokuvela kwi-plane okanye ngaphandle kwe-plane ye-graphene layers 33 ejikelezisiweyo ngokumalunga omnye nomnye. Ngokwahlukileyo, iipateni ze-electron diffraction kwi-Figure 5h, i (ehambelana nommandla we-NGF oboniswe kwi-Figure 5a) ibonisa ipateni enye [0001] kunye nobukhulu be-diffraction intensity ephezulu, ehambelana nobukhulu bezinto eziphathekayo. Le mizekelo ye-SAED ihambelana nesakhiwo somzobo esityebileyo kunye ne-intermediate orientation kune-FLG, njengoko ichazwe kwi-inferred index 64. Iimpawu zeempawu ze-crystalline ze-NGF zibonakalise ukuhlalisana kwe-crystallites ezimbini okanye ezintathu eziphezulu (okanye i-graphene). Eyona nto iphawuleka ngakumbi kwingingqi ye-FLG kukuba iikristale zinenqanaba elithile le-in-plane okanye ngaphandle kwenqwelomoya. Amasuntswana / iileyile zegraphite ezineengile zokujikeleza kwe-in-plane ye-17 °, 22 ° kunye ne-25 ° ziye zaxelwa ngaphambili kwi-NGF ekhuliswe kwiifilimu ze-Ni 64. Amaxabiso e-engile yokujikeleza abonwe kolu phononongo ahambelana nee-engile zokujikeleza ebezijongiwe ngaphambili (±1°) kwigraphene ye-BLG63 ejijekileyo.
Iimpawu zombane ze-NGF / SiO2 / Si zilinganiswe kwi-300 K kwindawo ye-10 × 3 mm2. Amaxabiso e-electron carrier concentration, ukuhamba kunye ne-conductivity yi-1.6 × 1020 cm-3, 220 cm2 V-1 C-1 kunye ne-2000 S-cm-1, ngokulandelanayo. Ukuhamba kunye nokuhamba kwexabiso le-NGF yethu ifana negraphite2 yendalo kwaye iphezulu kune-graphite ye-pyrolytic ekhoyo kakhulu yorhwebo (eveliswe kwi-3000 ° C) 29. Amaxabiso oxinzelelo lwe-electron carrier concentration are two orders of magnitude aphezulu kunezo zixelwe mva nje (7.25 × 10 cm-3) kwiifilim zegraphite micron ezityebileyo ezilungiselelwe kusetyenziswa ubushushu obuphezulu (3200 °C) polyimide sheets 20.
Senze kwakhona imilinganiselo yokudluliselwa kwe-UV ebonakalayo kwi-FS-NGF idluliselwe kwi-quartz substrates (Umfanekiso 6). I-spectrum ephumelayo ibonisa ukuhanjiswa ngokukhawuleza kwe-62% kuluhlu lwe-350-800 nm, ebonisa ukuba i-NGF iguquguquke ekukhanyeni okubonakalayo. Enyanisweni, igama elithi "KAUST" linokubonwa kwifoto yedijithali yesampulu kwi-Figure 6b. Nangona ulwakhiwo lwe-nanocrystalline lwe-NGF luhluke kwi-SLG, inani leengqimba linokuqikelelwa ngokuqikelelwa ngokusebenzisa umgaqo we-2.3% yokulahleka kokuhanjiswa kwinqanaba elongezelelweyo65. Ngokwalo budlelwane, inani le graphene layers nge 38% ilahleko yosulelo yi 21. I-NGF ekhulileyo ikakhulu iqulathe 300 graphene layers, okt malunga 100 nm ubukhulu (Fig. 1, SI5 kunye SI7). Ngoko ke, sicinga ukuba ukubonwa kwe-optical transparency kuhambelana nemimandla ye-FLG kunye ne-MLG, ekubeni isasazwa kuyo yonke ifilimu (iFig. 1, 3, 5 kunye ne-6c). Ukongeza kule datha yesakhiwo esingentla, i-conductivity kunye nokungafihli kukwaqinisekisa umgangatho ophezulu we-crystalline we-NGF edluliselweyo.
(a) Umlinganiselo we-UV obonakalayo wokudluliselwa, (b) ukudluliselwa kwe-NGF eqhelekileyo kwi-quartz usebenzisa isampuli yommeli. (c) I-Schematic ye-NGF (ibhokisi emnyama) enemimandla ye-FLG kunye ne-MLG esasazwe ngokulinganayo ephawulwe njengeemilo ezingwevu ezingakhethiyo kwisampulu (jonga uMzobo 1) (malunga ne-0.1-3% yendawo nge-100 μm2). Iimilo ezingacwangciswanga kunye nobukhulu bazo kumzobo zezenjongo zokubonisa kuphela kwaye azihambelani neendawo zokwenyani.
I-NGF eguquguqukayo ekhuliswe yi-CVD ngaphambili idluliselwe kwindawo engenanto ye-silicon kwaye isetyenziswe kwiiseli zelanga15,16. Isiphumo sokuguqulwa kwamandla (PCE) yi-1.5%. Ezi NGFs zenza imisebenzi emininzi efana ne-compound layers esebenzayo, iindlela zokuthutha intlawulo, kunye ne-electrodes ebonakalayo15,16. Nangona kunjalo, ifilimu yegraphite ayifani. Ukulungiswa okungaphezulu kuyadingeka ngokulawula ngokucophelela ukuchasana kwamaphepha kunye nokuhanjiswa kwe-optical ye-graphite electrode, ekubeni ezi zakhiwo zimbini zidlala indima ebalulekileyo ekunqumeni ixabiso le-PCE ye-solar cell15,16. Ngokuqhelekileyo, iifilimu ze-graphene ziyi-97.7% ezicacileyo ekukhanyeni okubonakalayo, kodwa zine-sheet resistance ye-200-3000 ohms / sq.16. Ukumelana nomphezulu weefilimu zegraphene kunokuncitshiswa ngokunyusa inani leeleya (ukudluliselwa okuphindaphindiweyo kweeleyile zegraphene) kunye ne-doping nge-HNO3 (~30 Ohm/sq.)66. Nangona kunjalo, le nkqubo ithatha ixesha elide kwaye iileya ezahlukeneyo zokudlulisa azisoloko zigcina uqhagamshelwano olulungileyo. Icala lethu langaphambili i-NGF ineepropati ezifana ne-conductivity 2000 S / cm, ukumelana nephepha lefilimu 50 ohm / sq. kunye no-62% obala, okwenza kube yinto esebenzayo kwiitshaneli eziqhubayo okanye i-counter electrode kwiiseli zelanga15,16.
Nangona ulwakhiwo kunye ne-surface chemistry ye-BS-NGF ifana ne-FS-NGF, uburhabaxa bayo buhluke ("Ukukhula kwe-FS- kunye ne-BS-NGF"). Ngaphambili, sasisebenzisa ifilimu ye-ultra-thin graphite22 njengenzwa yegesi. Ngoko ke, siye savavanya ukuba kunokwenzeka ukusebenzisa i-BS-NGF kwimisebenzi yokubona igesi (Umfanekiso we-SI10). Okokuqala, iinxalenye ze-mm2 ze-BS-NGF zidluliselwe kwi-interdigitating electrode sensor chip (Figure SI10a-c). Iinkcukacha zokwenziwa kwe-chip zazixelwe ngaphambili; indawo yayo esebenzayo enovakalelo yi-9 mm267. Kwimifanekiso ye-SEM (Umfanekiso we-SI10b kunye no-c), i-electrode yegolide engaphantsi ibonakala ngokucacileyo nge-NGF. Kwakhona, kunokubonwa ukuba i-chip coverage efanayo iphunyeziwe kuzo zonke iisampuli. Imilinganiselo yegesi yegesi yeegesi ezahlukeneyo zabhalwa (Umfanekiso we-SI10d) (Umfanekiso we-SI11) kunye nemilinganiselo yokuphendula okubangelwayo iboniswe kwiMifanekiso. SI10g. Mhlawumbi kunye nezinye iigesi eziphazamisayo ezibandakanya i-SO2 (200 ppm), i-H2 (2%), i-CH4 (200 ppm), i-CO2 (2%), i-H2S (200 ppm) kunye ne-NH3 (200 ppm). Omnye unobangela nguNO2. Ubume be-electrophilic yegesi22,68. Xa i-adsorbed kumphezulu wegraphene, inciphisa ukufunxwa kwangoku kwee-electron yinkqubo. Ukuthelekiswa kwexesha lokuphendula idatha ye-BS-NGF yenzwa kunye neenzwa ezipapashwe ngaphambili ziboniswe kwiThebhile ye-SI2. Indlela yokuvuselela i-NGF sensors usebenzisa i-UV plasma, i-O3 plasma okanye i-thermal (50-150 ° C) unyango lweesampuli eziveziweyo ziyaqhubeka, ngokufanelekileyo zilandelwa ukuphunyezwa kweenkqubo ezidibeneyo69.
Ngethuba lenkqubo ye-CVD, ukukhula kwegraphene kwenzeka kumacala omabini e-catalyst substrate41. Nangona kunjalo, i-BS-graphene ihlala ikhutshwa ngexesha lenkqubo yokudlulisa41. Kule sifundo, sibonisa ukuba ukukhula kwe-NGF ephezulu kunye nokudluliselwa kwe-NGF ye-polymer-free 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 ayibonakali ngokuthe ngqo kwi-precursor gas flow. Siphinde safumanisa ukuba uburhabaxa be-NiAR substrate buchaphazela uburhabaxa be-NGF. Ezi ziphumo zibonisa ukuba i-FS-NGF ekhulile iplani ingasetyenziselwa njengento engaphambili ye-graphene (nge-exfoliation method70) okanye njengendlela yokuqhubela phambili kwiiseli zelanga15,16. Ngokwahlukileyo, i-BS-NGF iya kusetyenziselwa ukufumanisa igesi (Umfanekiso we-SI9) kwaye mhlawumbi kwiinkqubo zokugcina amandla71,72 apho uburhabaxa bayo bomhlaba buya kuba luncedo.
Ukuqwalasela oku ngasentla, luncedo ukudibanisa umsebenzi okhoyo ngoku kunye neefilimu zegraphite ezipapashwe ngaphambili ezikhuliswe yi-CVD kunye nokusebenzisa i-nickel foil. Njengoko kunokubonwa kwiThebhile 2, uxinzelelo oluphezulu esilusebenzisileyo lwanciphisa ixesha lokusabela (inqanaba lokukhula) nakumaqondo obushushu aphantsi kakhulu (kuluhlu lwe-850-1300 °C). Sikwaphumelele ukukhula okukhulu kunesiqhelo, nto leyo ebonisa ukuba kungenzeka ukwanda. Kukho ezinye izinto ekufuneka ziqwalaselwe, ezinye zazo sizibandakanyile kwitheyibhile.
I-NGF enamacala amabini akumgangatho ophezulu yakhuliswa kwi-nickel foil yi-catalytic CVD. Ngokususa i-polymer substrates zendabuko (ezifana nezo zisetyenziswe kwi-graphene ye-CVD), sifezekisa ukuhanjiswa okumanzi okucocekileyo kunye nokungenasiphako kwe-NGF (ekhule ngasemva nangaphambili emacaleni e-nickel foil) kwiinkqubo ezahlukeneyo-ezibalulekileyo substrates. Ngokucacileyo, i-NGF ibandakanya imimandla ye-FLG kunye ne-MLG (ngokuqhelekileyo i-0.1% ukuya kwi-3% nge-100 µm2) edityaniswe kakuhle kwifilimu eshinyeneyo. I-TEM ye-Planar ibonisa ukuba le mimandla iqulunqwe ngamanqwanqwa amabini ukuya kwezintathu zegraphite / i-graphene (iikristale okanye iileya, ngokulandelanayo), ezinye zazo ezinokujikeleza kwe-10-20 °. Imimandla ye-FLG kunye ne-MLG inoxanduva lokubonakala kwe-FS-NGF ekukhanyeni okubonakalayo. Ngokubhekiselele kumaphepha angasemva, anokuthi athathwe ngokuhambelana namaphepha angaphambili kwaye, njengoko kubonisiwe, anokuba nenjongo esebenzayo (umzekelo, ukufunyanwa kwegesi). Ezi zifundo ziluncedo kakhulu ekunciphiseni inkunkuma kunye neendleko kwiinkqubo ze-CVD zamashishini.
Ngokubanzi, ubukhulu obuqhelekileyo be-CVD NGF bulele phakathi (i-low- kunye ne-multi-layer) i-graphene kunye ne-industrial (micrometer) amaphepha egraphite. Uluhlu lweempawu zabo ezinomdla, ezidityaniswe nendlela elula esiyiphuhlisileyo yokuvelisa kunye nokuthutha, yenza ezi filimu zifaneleke ngokukodwa kwizicelo ezifuna impendulo esebenzayo yegraphite, ngaphandle kweendleko zeenkqubo zokuvelisa amandla amashishini asebenzayo ngoku.
I-25-μm-thick nickel foil (i-99.5% ubunyulu, i-Goodfellow) ifakwe kwi-reactor ye-CVD yorhwebo (i-Aixtron 4-intshi ye-BMPro). Inkqubo yahlanjululwa nge-argon kwaye ikhutshwe kwi-base pressure ye-10-3 mbar. Emva koko kwafakwa i-nickel foil. kwi-Ar / H2 (Emva kokufakwa kwangaphambili kwe-Ni foil ye-5 min, i-foil yavezwa kuxinzelelo lwe-500 mbar kwi-900 ° C. I-NGF ifakwe kwi-flow CH4 / H2 (100 cm3 nganye) kwi-5 min. Isampuli yapholiswa kwiqondo lokushisa elingaphantsi kwe-700 ° C usebenzisa i-Ar flow (4000 cm3) kwi-40 ° C / min. Iinkcukacha malunga nokulungiswa kwenkqubo yokukhula kwe-NGF ichazwe kwenye indawo30.
I-morphology yomhlaba yesampuli yabonwa yi-SEM usebenzisa i-microscope ye-Zeiss Merlin (1 kV, 50 pA). Ubunzima besampulu yomhlaba kunye nobukhulu be-NGF balinganiswa ngokusebenzisa i-AFM (i-Dimension Icon SPM, i-Bruker). Imilinganiselo ye-TEM kunye ne-SAED yaqhutywa kusetyenziswa i-FEI Titan 80–300 Cubed microscope exhotyiswe ngompu wokugqama okuphezulu komhlaba (300 kV), i-FEI Wien yohlobo lwe-monochromator kunye ne-CEOS lens spherical aberration corrector ukufumana iziphumo zokugqibela. isisombululo sesithuba 0.09 nm. Iisampulu ze-NGF zaye zakhutshelwa kwiigridi zobhedu ezigqunywe ngekhabhoni ukuze zifumane umfanekiso we-TEM ocaba kunye nohlalutyo lwesakhiwo se-SAED. Ke, uninzi lweesampulu zesampulu zixhonywe kwiipores ze-membrane exhasayo. Iisampuli ezidlulisiweyo ze-NGF zahlalutywa yi-XRD. Iipateni ze-X-ray diffraction zifunyenwe kusetyenziswa i-powder diffractometer (i-Brucker, i-D2 yesigaba shifter kunye nomthombo we-Cu Kα, i-1.5418 Å kunye ne-LYNXEYE detector) usebenzisa umthombo we-Cu radiation kunye ne-beam spot diameter ye-3 mm.
Imilinganiselo emininzi yeendawo zeRaman zarekhodwa kusetyenziswa imakroskopu edibanisayo (Alpha 300 RA, WITeC). I-laser ye-532 nm enamandla aphantsi e-excitation (25%) yayisetyenziselwa ukuphepha iziphumo ezibangelwa yi-thermal. I-X-ray photoelectron spectroscopy (XPS) yenziwa kwi-Kratos Axis Ultra spectrometer phezu kwesampulu yommandla we-300 × 700 μm2 kusetyenziswa i-monochromatic Al Kα radiation (hν = 1486.6 eV) kumandla e-150 W. Amandla othumelo lwe-160 eV kunye ne-20 eV, ngokulandelelanayo. Iisampulu ze-NGF ezidluliselwe kwi-SiO2 zanqunyulwa zibe ziingceba (3 × 10 mm2 nganye) kusetyenziswa i-PLS6MW (1.06 μm) i-ytterbium fiber laser kwi-30 W. Uqhagamshelwano lwe-Copper yocingo (ama-50 μm ubukhulu) zenziwe kusetyenziswa i-silver paste phantsi kwe-microscope ebonakalayo. Ukuthuthwa kombane kunye novavanyo lwempembelelo yeHolo lwenziwa kwezi sampuli kwi-300 K kunye nokwahluka kwamagnetic field ± 9 Tesla kwinkqubo yokulinganisa iipropati ezibonakalayo (PPMS EverCool-II, Quantum Design, USA). Ukuhanjiswa kwe-UV-vis spectra kwarekhodwa kusetyenziswa i-Lambda 950 UV-vis spectrophotometer kuluhlu lwe-350-800 nm NGF ekhutshelwe kwi-quartz substrates kunye neesampuli zereferensi zequartz.
Inzwa yokumelana neekhemikhali (i-interdigitated electrode chip) ifakwe kwibhodi yesekethe eprintiweyo yesiko 73 kwaye ukuchasana kukhutshwe ngokukhawuleza. Ibhodi yesekethe eprintiweyo apho ifowuni ifakwe khona idibaniswe kwii-terminals zoqhagamshelwano kwaye ifakwe ngaphakathi kwegumbi lokuva igesi 74. Imilinganiselo yokuchasana ithathwe kwi-voltage ye-1 V kunye ne-scan eqhubekayo ukusuka ekuhlanjululweni ukuya kwi-exposure yegesi kwaye ihlanjululwe kwakhona. Igumbi laqala ukucocwa ngokucoca nge-nitrogen kwi-200 cm3 ngeyure ye-1 ukuqinisekisa ukususwa kwazo zonke ezinye izihlalutyi ezikhoyo kwigumbi, kubandakanywa nomswakama. Abahlalutyi ngabanye baye bakhululwa ngokukhawuleza kwigumbi kwinqanaba elifanayo lokuhamba kwe-200 cm3 ngokuvala i-cylinder ye-N2.
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