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Mafilimu a Nanoscale graphite (NGFs) ndi ma nanomatadium amphamvu omwe amatha kupangidwa ndi mpweya wochititsa chidwi wamankhwala, koma mafunso akadali okhudza kusamutsa kwawo kosavuta komanso momwe morphology yamadzimadzi imakhudzira kugwiritsidwa ntchito kwawo pazida zam'badwo wotsatira. Apa tikufotokozera kukula kwa NGF kumbali zonse ziwiri za polycrystalline nickel zojambulazo (dera la 55 cm2, makulidwe pafupifupi 100 nm) ndi kusamutsidwa kwake kopanda polima (kutsogolo ndi kumbuyo, kudera mpaka 6 cm2). Chifukwa cha morphology ya chojambula chothandizira, mafilimu awiri a kaboni amasiyana muzochita zawo zakuthupi ndi makhalidwe ena (monga roughness pamwamba). Timasonyeza kuti NGFs ndi rougher backside ndi bwino kuti NO2 kuzindikira, pamene yosalala ndi more conductive NGFs kutsogolo (2000 S/cm, sheet resistance - 50 ohms/m2) akhoza kukhala conductors yotheka. njira kapena electrode ya cell solar (popeza imatumiza 62% ya kuwala kowoneka). Ponseponse, njira zofotokozera za kukula ndi zoyendetsa zingathandize kuzindikira NGF ngati njira ina ya carbon pa ntchito zamakono kumene mafilimu a graphene ndi micron-thick graphite sali oyenera.
Graphite ndi zinthu zomwe zimagwiritsidwa ntchito kwambiri m'mafakitale. Makamaka, graphite ili ndi mphamvu yocheperako komanso yotsika kwambiri mundege ndi machulukidwe amagetsi, ndipo imakhala yokhazikika m'malo otentha komanso owopsa kwambiri1,2. Flake graphite ndichinthu chodziwika bwino choyambira pa kafukufuku wa graphene3. Ikasinthidwa kukhala mafilimu opyapyala, imatha kugwiritsidwa ntchito pazinthu zosiyanasiyana, kuphatikiza zoyatsira kutentha kwa zida zamagetsi monga mafoni a m'manja4,5,6,7, monga zinthu zogwira ntchito mu masensa8,9,10 komanso chitetezo chamagetsi chamagetsi11. 12 ndi mafilimu a lithography mu ultraviolet13,14 kwambiri, kuchititsa njira m'maselo a dzuwa15,16. Pazinthu zonsezi, zingakhale zopindulitsa kwambiri ngati madera akuluakulu a mafilimu a graphite (NGFs) okhala ndi makulidwe olamulidwa mu nanoscale <100 nm akhoza kupangidwa ndi kunyamulidwa mosavuta.
Mafilimu a graphite amapangidwa ndi njira zosiyanasiyana. Nthawi ina, kuyika ndi kukulitsa kotsatiridwa ndi exfoliation kunagwiritsidwa ntchito kupanga ma graphene flakes10,11,17. Ma flakes ayenera kukonzedwanso kukhala mafilimu a makulidwe ofunikira, ndipo nthawi zambiri zimatenga masiku angapo kuti apange mapepala owundana a graphite. Njira ina ndikuyamba ndi ma graphtable olimba ma precursors. M'makampani, mapepala a ma polima amapangidwa ndi carbonized (pa 1000-1500 ° C) kenako amajambula (pa 2800-3200 ° C) kuti apange zipangizo zosanjikiza bwino. Ngakhale kuti mawonekedwe a mafilimuwa ndi apamwamba, mphamvu zogwiritsira ntchito mphamvu ndizofunika1,18,19 ndipo makulidwe ocheperako amangokhala ma microns1,18,19,20 ochepa.
Catalytic chemical vapor deposition (CVD) ndi njira yodziwika bwino yopangira mafilimu a graphene ndi ultrathin graphite (<10 nm) okhala ndi mawonekedwe apamwamba komanso okwera mtengo21,22,23,24,25,26,27. Komabe, poyerekeza ndi kukula kwa mafilimu a graphene ndi ultrathin graphite28, kukula kwa madera akuluakulu ndi / kapena kugwiritsa ntchito NGF pogwiritsa ntchito CVD sikumafufuzidwa pang'ono11,13,29,30,31,32,33.
Mafilimu a graphene ndi ma graphite omwe amapangidwa ndi CVD nthawi zambiri amafunika kusamutsidwa ku magawo ogwira ntchito34. Kusamutsa filimu woonda kumeneku kumaphatikizapo njira ziwiri zazikulu35: (1) kusamutsa kosasunthika36,37 ndi (2) etch-based wet chemical transfer (gawo lothandizira)14,34,38. Njira iliyonse ili ndi ubwino ndi zovuta zina ndipo iyenera kusankhidwa malinga ndi momwe ikufunira, monga momwe tafotokozera kwina35,39. Kwa mafilimu a graphene/graphite omwe amakula pazigawo zothandizira, kusamutsidwa kudzera muzitsulo zamadzimadzi (zomwe polymethyl methacrylate (PMMA) ndizomwe zimagwiritsidwa ntchito kwambiri zothandizira) zimakhalabe chisankho choyamba13,30,34,38,40,41,42. Inu et al. Zinanenedwa kuti palibe polima yomwe idagwiritsidwa ntchito potengera NGF (kukula kwachitsanzo pafupifupi 4 cm2) 25,43, koma palibe tsatanetsatane wokhudzana ndi kukhazikika kwachitsanzo ndi / kapena kusamalira panthawi yopititsa; Njira zonyowa zama chemistry pogwiritsa ntchito ma polima zimakhala ndi masitepe angapo, kuphatikiza kugwiritsa ntchito ndikuchotsa kotsatira kwa gawo la polima30,38,40,41,42. Izi zimakhala ndi zovuta: mwachitsanzo, zotsalira za polima zimatha kusintha mawonekedwe a film38. Kukonza kowonjezera kumatha kuchotsa polima yotsalira, koma masitepe owonjezerawa amawonjezera mtengo ndi nthawi yopanga mafilimu38,40. Panthawi ya kukula kwa CVD, graphene imayikidwa osati kutsogolo kwa chojambula chothandizira (mbali yomwe ikuyang'anizana ndi kutuluka kwa nthunzi), komanso kumbuyo kwake. Komabe, zotsirizirazi zimatengedwa ngati zowonongeka ndipo zimatha kuchotsedwa mwamsanga ndi plasma38,41 yofewa. Kubwezeretsanso filimuyi kungathandize kukulitsa zokolola, ngakhale zitakhala zotsika kwambiri kuposa filimu ya carbon.
Pano, timapereka lipoti la kukonzekera kwa NGF ya NGF yokhala ndi mawonekedwe apamwamba kwambiri pa polycrystalline nickel zojambulazo ndi CVD. Zinayesedwa momwe kuuma kwa kutsogolo ndi kumbuyo kwa zojambulazo kumakhudzira morphology ndi mapangidwe a NGF. Timawonetsanso kusamutsa kwa NGF kopanda mtengo komanso kosawononga chilengedwe kuchokera kumbali zonse za faifi ya nickel kupita ku magawo ambiri ndikuwonetsa momwe makanema akutsogolo ndi kumbuyo ali oyenera kugwiritsa ntchito zosiyanasiyana.
Magawo otsatirawa akukambirana makulidwe osiyanasiyana a filimu ya graphite malinga ndi kuchuluka kwa zigawo za graphene zodzaza: (i) graphene imodzi (SLG, 1 wosanjikiza), (ii) graphene yochepa (FLG, <10 layers), (iii) multilayer graphene ( MLG, 10-30 zigawo) ndi (iv) NGF (~ 300 zigawo). Chotsatiracho ndi makulidwe odziwika bwino omwe amawonetsedwa ngati gawo la gawo (pafupifupi 97% dera pa 100 µm2)30. Ndicho chifukwa chake filimu yonseyo imatchedwa NGF.
Zojambula za nickel za polycrystalline zomwe zimagwiritsidwa ntchito popanga mafilimu a graphene ndi ma graphite zimakhala ndi mawonekedwe osiyanasiyana chifukwa cha kupanga kwawo ndi kukonzanso kotsatira. Posachedwapa tidapereka lipoti la kafukufuku kuti tikwaniritse kukula kwa NGF30. Timasonyeza kuti magawo a ndondomeko monga nthawi yochepetsera ndi kupanikizika kwa chipinda panthawi ya kukula kumagwira ntchito yofunika kwambiri popeza ma NGF a makulidwe ofanana. Pano, tinafufuzanso za kukula kwa NGF pazitsulo zopukutidwa (FS) ndi malo osapukutidwa kumbuyo (BS) a zojambula za nickel (mkuyu 1a). Mitundu itatu ya zitsanzo za FS ndi BS zinafufuzidwa, zomwe zalembedwa mu Table 1. Poyang'anitsitsa, kukula kwa yunifolomu ya NGF kumbali zonse za nickel zojambulazo (NiAG) kumawoneka ndi kusintha kwa mtundu wa gawo lalikulu la Ni substrate kuchokera ku khalidwe lachitsulo siliva. imvi kwa matte imvi mtundu (mkuyu 1a); miyeso yaying'ono idatsimikiziridwa (mkuyu 1b, c). Mtundu wa Raman wa FS-NGF womwe umawonedwa m'dera lowala ndikuwonetseredwa ndi mivi yofiira, yabuluu ndi lalanje mu Chithunzi 1b ikuwonetsedwa mu Chithunzi 1c. Makhalidwe a Raman nsonga za graphite G (1683 cm−1) ndi 2D (2696 cm−1) zimatsimikizira kukula kwa crystalline NGF (Mkuyu 1c, Table SI1). Mufilimu yonseyi, chiwonetsero cha Raman chokhala ndi kuchuluka kwamphamvu (I2D/IG) ~ 0.3 chinawonedwa, pomwe mawonekedwe a Raman okhala ndi I2D/IG = 0.8 sanawonedwe. Kupanda nsonga zolakwika (D = 1350 cm-1) mufilimu yonseyi kumasonyeza khalidwe lapamwamba la kukula kwa NGF. Zotsatira zofanana za Raman zinapezedwa pa chitsanzo cha BS-NGF (Chithunzi SI1 a ndi b, Table SI1).
Kuyerekeza kwa NiAG FS- ndi BS-NGF: (a) Chithunzi cha chitsanzo cha NGF (NiAG) chosonyeza kukula kwa NGF pa sikelo yopyapyala (55 cm2) ndi zotsatira za BS- ndi FS-Ni zojambula zojambulazo, (b) FS-NGF Zithunzi/ Ni zopezedwa ndi maikulosikopu kuwala, (c) mmene Raman sipekitiramu ojambulidwa pa malo osiyana mu gulu b, (d, f) SEM zithunzi pa magnifications osiyana pa FS-NGF/Ni, (e, g) SEM zithunzi pa magnifications osiyana Amakhazikitsa BS -NGF/Ni. Muvi wabuluu umasonyeza dera la FLG, muvi wa lalanje umasonyeza dera la MLG (pafupi ndi dera la FLG), muvi wofiyira umasonyeza dera la NGF, ndipo muvi wa magenta umasonyeza khola.
Popeza kukula kumadalira makulidwe a gawo loyamba, kukula kwa kristalo, kuyang'ana, ndi malire a tirigu, kukwaniritsa kulamulira koyenera kwa makulidwe a NGF pamadera akuluakulu kumakhalabe vuto20,34,44. Kafukufukuyu adagwiritsa ntchito zomwe tidasindikiza kale30. Izi zimapanga dera lowala la 0.1 mpaka 3% pa 100 µm230. M'magawo otsatirawa, timapereka zotsatira zamitundu yonse ya zigawo. Zithunzi zokulirapo za SEM zikuwonetsa kukhalapo kwa madera angapo owoneka bwino mbali zonse ziwiri (mkuyu 1f, g), kuwonetsa kukhalapo kwa zigawo za FLG ndi MLG30,45. Izi zinatsimikiziridwanso ndi kufalikira kwa Raman (mkuyu 1c) ndi zotsatira za TEM (zokambidwa pambuyo pake mu gawo "FS-NGF: kapangidwe ndi katundu"). Madera a FLG ndi MLG omwe amawonedwa pa zitsanzo za FS- ndi BS-NGF/Ni (kutsogolo ndi kumbuyo NGF yokulirapo pa Ni) mwina idakula panjere zazikulu za Ni(111) zomwe zidapangidwa panthawi isanakwane22,30,45. Kupinda kunawonedwa mbali zonse (mkuyu. 1b, yolembedwa ndi mivi yofiirira). Izi zopindika nthawi zambiri zimapezeka m'mafilimu opangidwa ndi CVD-graphene ndi graphite chifukwa cha kusiyana kwakukulu kwa coefficient of thermal expansion pakati pa graphite ndi nickel substrate30,38.
Chithunzi cha AFM chinatsimikizira kuti chitsanzo cha FS-NGF chinali chosalala kuposa chitsanzo cha BS-NGF (Chithunzi SI1) (Chithunzi SI2). Mizu imatanthawuza lalikulu (RMS) makulidwe a FS-NGF/Ni (mkuyu SI2c) ndi BS-NGF/Ni (mkuyu SI2d) ndi 82 ndi 200 nm, motero (kuyezedwa kudera la 20 × 20 mz2). Kukhwimitsa kwakukulu kumatha kumveka potengera kusanthula kwapamtunda kwa faifi ya nickel (NiAR) m'malo omwe alandilidwa (Chithunzi SI3). Zithunzi za SEM za FS ndi BS-NiAR zikuwonetsedwa mu Zithunzi SI3a-d, zowonetsa ma morphologies osiyanasiyana: zojambulazo za FS-Ni zopukutidwa zili ndi tinthu tating'onoting'ono ta nano- ndi micron, pomwe zojambulazo zosapukutidwa za BS-Ni zimawonetsa makwerero opangira. ngati particles ndi mphamvu mkulu. ndi kugwa. Zithunzi zotsika komanso zapamwamba za zojambula za nickel (NiA) zikuwonetsedwa mu Chithunzi SI3e–h. M'ziwerengerozi, tikhoza kuona kukhalapo kwa tinthu tating'ono ta nickel tating'onoting'ono tating'ono mbali zonse za faifi tambala (mkuyu SI3e–h). Mbewu zazikulu zitha kukhala ndi mawonekedwe a Ni(111), monga momwe adanenera kale30,46. Pali kusiyana kwakukulu kwa nickel foil morphology pakati pa FS-NiA ndi BS-NiA. Kukula kwakukulu kwa BS-NGF / Ni chifukwa cha malo osapukutidwa a BS-NiAR, omwe pamwamba pake amakhalabe ovuta kwambiri ngakhale atatha annealing (Chithunzi SI3). Mtundu uwu wa mawonekedwe apamwamba asanayambe kukula amalola kuti graphene ndi mafilimu a graphite aziwongoleredwa. Zindikirani kuti gawo lapansi loyambirira lidakonzedwanso panthawi ya kukula kwa graphene, zomwe zidachepetsa kukula kwambewu ndikuwonjezera kuuma kwa gawo lapansi poyerekeza ndi zojambulazo ndi chothandizira film22.
Kukonza bwino makulidwe a gawo lapansi, nthawi yothira (kukula kwa tirigu)30,47 ndi kutulutsa43 kudzathandiza kuchepetsa kufana kwa makulidwe a NGF ku µm2 ndi/kapenanso nm2 sikelo (ie, kusiyanasiyana kwa ma nanometer ochepa). Pofuna kuwongolera kuuma kwa gawo lapansi, njira monga kupukuta kwa electrolytic kwa chojambula cha nickel chotsatira chitha kuganiziridwa48. Chojambula cha nickel chopangidwa kale chikhoza kutsekedwa kutentha pang'ono (<900 °C) 46 ndi nthawi (< 5 min) kupewa kupangidwa kwa mbewu zazikulu za Ni(111) (zomwe zimakhala zopindulitsa pakukula kwa FLG).
SLG ndi FLG graphene sangathe kulimbana ndi kugwedezeka kwa pamwamba kwa asidi ndi madzi, zomwe zimafuna zigawo zothandizira makina panthawi yonyowa kutengerapo mankhwala22,34,38. Mosiyana ndi chonyowa mankhwala kutengerapo wa polima-anathandiza single-wosanjikiza graphene38, tinapeza kuti mbali zonse za NGF monga wamkulu akhoza kusamutsidwa popanda polima thandizo, monga momwe chithunzi 2a (onani Chithunzi SI4a kuti mudziwe zambiri). Kusamutsa kwa NGF ku gawo lopatsidwa kumayamba ndikunyowa kwa filimu yapansi panthaka ya Ni30.49. Zitsanzo zokulirapo za NGF/Ni/NGF zidayikidwa usiku wonse mu 15 mL ya 70% HNO3 yochepetsedwa ndi 600 mL yamadzi a deionized (DI). Pambuyo pa Ni zojambulazo zimasungunuka kwathunthu, FS-NGF imakhalabe yosalala ndipo imayandama pamwamba pa madzi, monga chitsanzo cha NGF / Ni / NGF, pamene BS-NGF imamizidwa m'madzi (Mkuyu 2a, b). NGF yakutaliyo idasamutsidwa kuchokera ku beaker imodzi yomwe inali ndi madzi osungunuka kupita ku beaker ina ndipo NGF yokhayo idatsukidwa bwino, kubwereza kanayi mpaka sikisi kudzera mu mbale yagalasi ya concave. Potsirizira pake, FS-NGF ndi BS-NGF zinayikidwa pa gawo lapansi lofunidwa (Mkuyu 2c).
Polima wopanda chonyowa mankhwala kutengerapo ndondomeko ya NGF wokulirapo pa faifi tambala: (a) Ndondomeko yoyenda chithunzi (onani Chithunzi SI4 kuti mumve zambiri), (b) Digital chithunzi cha olekanitsidwa NGF pambuyo Ni etching (2 zitsanzo), (c) Chitsanzo FS - ndi BS-NGF kusamutsira ku gawo lapansi la SiO2/Si, (d) FS-NGF kusamutsira ku gawo lapansi la opaque polima, (e) BS-NGF kuchokera pachitsanzo chomwecho monga gulu d (logawidwa m'magawo awiri), kutumizidwa ku pepala la C lagolide. ndi Nafion (gawo losinthika lowoneka bwino, m'mbali zolembedwa ndi ngodya zofiira).
Dziwani kuti kutengerako kwa SLG komwe kumachitidwa pogwiritsa ntchito njira zonyowa zosinthira mankhwala kumafuna nthawi yokwanira yokonza maola 20-24 38. Ndi njira yosinthira yopanda polima yomwe ikuwonetsedwa pano (Chithunzi SI4a), nthawi yonse yosinthira NGF yosinthira imachepetsedwa kwambiri (pafupifupi maola 15). Njirayi imakhala ndi: (Khwerero 1) Konzani yankho la etching ndikuyikamo chitsanzo (~ 10 minutes), kenaka dikirani usiku wonse kwa Ni etching (~ 7200 minutes), (Khwerero 2) Muzimutsuka ndi madzi osakaniza (Step - 3) . sungani m'madzi opangidwa ndi deionized kapena tumizani ku gawo lapansi (20 min). Madzi otsekedwa pakati pa NGF ndi matrix ochuluka amachotsedwa ndi capillary action (pogwiritsa ntchito pepala lopukuta) 38, ndiye kuti madontho otsala amadzi amachotsedwa ndi kuyanika kwachilengedwe (pafupifupi 30 min), ndipo pamapeto pake chitsanzocho chimawuma kwa 10 min. mphindi mu uvuni wosakira (10-1 mbar) pa 50-90 °C (60 min) 38.
Graphite amadziwika kuti amapirira kukhalapo kwa madzi ndi mpweya pa kutentha kwambiri (≥ 200 °C) 50,51,52. Tinayesa zitsanzo pogwiritsa ntchito ma Raman spectroscopy, SEM, ndi XRD titatha kusungidwa m'madzi osakanizidwa kutentha kutentha komanso m'mabotolo osindikizidwa kulikonse kuyambira masiku angapo mpaka chaka chimodzi (Chithunzi SI4). Palibe kuwonongeka kowonekera. Chithunzi 2c chikuwonetsa FS-NGF yaulere ndi BS-NGF m'madzi osungunuka. Tidawagwira pagawo la SiO2 (300 nm)/Si, monga tawonera koyambirira kwa Chithunzi 2c. Kuonjezera apo, monga momwe tawonetsera pa Chithunzi 2d, e, NGF yosalekeza ikhoza kusamutsidwa ku magawo osiyanasiyana monga ma polima (Thermabright polyamide kuchokera ku Nexolve ndi Nafion) ndi pepala la carbon lokutidwa ndi golide. FS-NGF yoyandama idayikidwa mosavuta pagawo laling'ono (mkuyu 2c, d). Komabe, zitsanzo za BS-NGF zazikulu kuposa 3 cm2 zinali zovuta kuzigwiritsa ntchito zitamizidwa kwathunthu m'madzi. Nthawi zambiri, akayamba kugudubuza m'madzi, chifukwa chosamalira mosasamala nthawi zina amaswa magawo awiri kapena atatu (mkuyu 2e). Ponseponse, tinatha kukwaniritsa kusamutsidwa kopanda polima kwa PS- ndi BS-NGF (kusamutsa mosalekeza popanda NGF / Ni / NGF kukula pa 6 cm2) kwa zitsanzo mpaka 6 ndi 3 cm2 m'dera, motero. Zidutswa zilizonse zazikulu kapena zazing'ono zotsalira zitha kukhala (zowoneka mosavuta munjira yotsekera kapena madzi osungunula) pagawo lomwe mukufuna (~ 1 mm2, Chithunzi SI4b, onani chitsanzo chomwe chimasamutsidwa ku gululi yamkuwa monga "FS-NGF: Kapangidwe ndi Katundu (kukambidwa) pansi pa "Structure and Properties") kapena sungani kuti mugwiritse ntchito mtsogolo (Chithunzi SI4). Kutengera muyeso uwu, timayesa kuti NGF ikhoza kubwezeredwa muzokolola mpaka 98-99% (pambuyo pa kukula kwa kusamutsidwa).
Zitsanzo zosinthira popanda polima zidawunikidwa mwatsatanetsatane. Makhalidwe apamwamba a morphological omwe amapezeka pa FS- ndi BS-NGF / SiO2 / Si (mkuyu 2c) pogwiritsa ntchito microscope (OM) ndi SEM zithunzi (mkuyu SI5 ndi mkuyu 3) anasonyeza kuti zitsanzozi zinasamutsidwa popanda maikulosikopu. Zowonongeka zowoneka bwino zamapangidwe monga ming'alu, mabowo, kapena malo ovundukuka. Zopindika pa NGF yomwe ikukula (mkuyu 3b, d, yodziwika ndi mivi yofiirira) idakhalabe yosasunthika pambuyo pa kusamutsidwa. Ma FS- ndi BS-NGF onse amapangidwa ndi zigawo za FLG (zigawo zowala zosonyezedwa ndi mivi ya buluu pa Chithunzi 3). Chodabwitsa n'chakuti, mosiyana ndi madera ochepa owonongeka omwe amawonedwa panthawi yopititsa mafilimu a polymer a ultrathin graphite mafilimu, zigawo zingapo za FLG ndi MLG za micron zolumikizana ndi NGF (zodziwika ndi mivi ya buluu pa Chithunzi 3d) zinasamutsidwa popanda ming'alu kapena kusweka (Chithunzi 3d) . 3). . Kukhulupirika kwamakina kudatsimikizidwanso pogwiritsa ntchito zithunzi za TEM ndi SEM za NGF zosamutsidwa pamagulu amkuwa amkuwa, monga momwe tafotokozera pambuyo pake ("FS-NGF: Structure and Properties"). BS-NGF/SiO2/Si yosamutsidwa ndi yovuta kuposa FS-NGF/SiO2/Si yokhala ndi ma rms a 140 nm ndi 17 nm, motsatana, monga momwe tawonetsera pa Chithunzi SI6a ndi b (20 × 20 μm2). Mtengo wa RMS wa NGF umasamutsidwa ku gawo lapansi la SiO2 / Si (RMS <2 nm) ndilotsika kwambiri (pafupifupi nthawi za 3) kusiyana ndi NGF yomwe yakula pa Ni (Chithunzi SI2), kusonyeza kuti kuuma kowonjezereka kungagwirizane ndi Ni pamwamba. Kuphatikiza apo, zithunzi za AFM zomwe zidachitika m'mphepete mwa FS- ndi BS-NGF / SiO2 / Si zitsanzo zidawonetsa makulidwe a NGF a 100 ndi 80 nm, motsatana (mkuyu SI7). Makulidwe ang'onoang'ono a BS-NGF atha kukhala chifukwa cha mawonekedwe osawonekera mwachindunji ndi mpweya woyambira.
Kusamutsidwa NGF (NiAG) popanda polima pa SiO2/Si kagawo kakang'ono (onani Chithunzi 2c): (a,b) Zithunzi za SEM za FS-NGF zosamutsidwa: kutsika ndi kukulitsa kwakukulu (zogwirizana ndi bwalo lalalanje mu gululo). Malo enieni) - a). (c, d) Zithunzi za SEM zosamutsidwa BS-NGF: kutsika komanso kukulira kwakukulu (kogwirizana ndi malo omwe akuwonetsedwa ndi lalikulu lalalanje mu gulu c). (e, f) Zithunzi za AFM za FS- ndi BS-NGF zosamutsidwa. Muvi wabuluu umayimira dera la FLG - kusiyanitsa kowala, muvi wa cyan - kusiyanitsa kwakuda kwa MLG, muvi wofiyira - kusiyanitsa kwakuda kumayimira dera la NGF, muvi wa magenta umayimira khola.
The mankhwala zikuchokera wamkulu ndi anasamutsidwa FS- ndi BS-NGFs anali kusanthula X-ray photoelectron spectroscopy (XPS) (mkuyu. 4). Chiwopsezo chofooka chinawonedwa mu mawonekedwe oyezera (mkuyu 4a, b), wofanana ndi gawo la Ni substrate (850 eV) la FS- ndi BS-NGF (NiAG) yomwe yakula. Palibe nsonga pazithunzi zoyezera za FS- ndi BS-NGF / SiO2 / Si (mkuyu 4c; zotsatira zofanana za BS-NGF / SiO2 / Si sizikusonyezedwa), kusonyeza kuti palibe kuipitsidwa kwa Ni yotsalira pambuyo pa kusamutsidwa. . Zithunzi 4d-f zimasonyeza mawonekedwe apamwamba a C 1 s, O 1 s ndi Si 2p mphamvu za FS-NGF/SiO2/Si. Mphamvu yomanga ya C 1 s ya graphite ndi 284.4 eV53.54. Maonekedwe a mzere wa nsonga za graphite nthawi zambiri amatengedwa ngati asymmetrical, monga momwe chithunzi 4d54 chikusonyezera. Chiwonetsero chapamwamba chapamwamba cha C 1 s spectrum (mkuyu 4d) chinatsimikiziranso kusamutsa koyera (ie, palibe zotsalira za polima), zomwe zimagwirizana ndi maphunziro apitalo38. Mizere yopingasa ya C 1 s spectra ya chitsanzo chatsopano (NiAG) ndi pambuyo pa kusamutsidwa ndi 0.55 ndi 0.62 eV, motsatira. Izi ndizokwera kuposa za SLG (0.49 eV ya SLG pagawo la SiO2)38. Komabe, zikhalidwezi ndizocheperako kuposa momwe zidanenedwapo kale za zitsanzo za pyrolytic graphene (~ 0.75 eV) 53,54,55, zomwe zikuwonetsa kusakhalapo kwa malo opanda mpweya wa kaboni pazomwe zilipo. Ma C 1 s ndi O 1 s mawonekedwe apansi amakhalanso opanda mapewa, kuthetsa kufunikira kwapamwamba kwambiri pa deconvolution54. Pali nsonga ya π → π* yozungulira 291.1 eV, yomwe nthawi zambiri imawonedwa m'ma graphite. Zizindikiro za 103 eV ndi 532.5 eV mu Si 2p ndi O 1 s core level spectra (onani Mkuyu 4e, f) amatchulidwa ndi gawo la SiO2 56, motsatira. XPS ndi njira yowonongeka pamwamba, kotero zizindikiro zogwirizana ndi Ni ndi SiO2 zomwe zadziwika kale ndi pambuyo pa kusamutsidwa kwa NGF, motero, zimaganiziridwa kuti zimachokera ku dera la FLG. Zotsatira zofananira zidawonedwa pazosamutsidwa za BS-NGF (zosawonetsedwa).
Zotsatira za NiAG XPS: (ac) Kafukufuku wamitundu yosiyanasiyana ya atomiki ya FS-NGF/Ni, BS-NGF/Ni ndikusamutsa FS-NGF/SiO2/Si, motsatana. (d-f) Mawonekedwe apamwamba kwambiri a magulu apakati C 1 s, O 1s ndi Si 2p a chitsanzo cha FS-NGF/SiO2/Si.
Ubwino wonse wa makhiristo a NGF omwe adasamutsidwa adayesedwa pogwiritsa ntchito X-ray diffraction (XRD). Mawonekedwe a XRD (mkuyu SI8) wa FS- ndi BS-NGF / SiO2 / Si amasonyeza kukhalapo kwa nsonga za diffraction (0 0 0 2) ndi (0 0 0 4) pa 26.6 ° ndi 54.7 °, zofanana ndi graphite. . Izi zimatsimikizira khalidwe lapamwamba la crystalline la NGF ndipo limagwirizana ndi mtunda wa interlayer wa d = 0.335 nm, womwe umasungidwa pambuyo pa sitepe yotengerapo. Kuchuluka kwa nsonga ya diffraction (0 0 0 2) ndi pafupifupi nthawi za 30 za nsonga ya diffraction (0 0 0 4), kusonyeza kuti ndege ya NGF crystal ikugwirizana bwino ndi chitsanzo cha pamwamba.
Malinga ndi zotsatira za SEM, Raman spectroscopy, XPS ndi XRD, khalidwe la BS-NGF/Ni linapezeka kuti ndilofanana ndi la FS-NGF/Ni, ngakhale kuti rms roughness yake inali yokwera pang'ono (Zithunzi SI2, SI5) ndi SI7).
Ma SLG okhala ndi zigawo zothandizira polima mpaka 200 nm wandiweyani amatha kuyandama pamadzi. Kukonzekera uku kumagwiritsidwa ntchito kwambiri polima-assisted wet chemical transfer process22,38. Graphene ndi graphite ndi hydrophobic (ngodya yonyowa 80-90 °) 57. Mphamvu zamphamvu za graphene ndi FLG zanenedwa kuti ndi zathyathyathya, zokhala ndi mphamvu zochepa (~ 1 kJ/mol) zoyendetsera madzi kumtunda58. Komabe, mphamvu zowerengera zowerengera zamadzi ndi graphene ndi zigawo zitatu za graphene ndi pafupifupi - 13 ndi - 15 kJ / mol, 58 motero, kusonyeza kuti kugwirizana kwa madzi ndi NGF (pafupifupi zigawo za 300) ndizochepa poyerekeza ndi graphene. Ichi chikhoza kukhala chimodzi mwa zifukwa zomwe NGF yodziyimira payokha imakhalabe yathyathyathya pamwamba pa madzi, pamene freestanding graphene (yomwe imayandama m'madzi) imapindika ndikusweka. NGF ikamizidwa kwathunthu m'madzi (zotsatira zake zimakhala zofanana ndi NGF yovuta komanso yosalala), m'mphepete mwake amapindika (Chithunzi SI4). Pankhani ya kumizidwa kwathunthu, zikuyembekezeka kuti mphamvu yolumikizana ndi madzi ya NGF imakhala pafupifupi kawiri (poyerekeza ndi NGF yoyandama) komanso kuti m'mphepete mwa khola la NGF kukhalabe ndi ngodya yayikulu (hydrophobicity). Tikukhulupirira kuti njira zitha kupangidwa kuti tipewe kupindika m'mphepete mwa ma NGF ophatikizidwa. Njira imodzi ndiyo kugwiritsa ntchito zosungunulira zosakanizika kuti zisinthe kunyowetsa kwa filimu ya graphite59.
Kusamutsidwa kwa SLG kupita kumitundu yosiyanasiyana ya magawo kudzera munjira zonyowa zosinthira mankhwala zidanenedwa kale. Ambiri amavomereza kuti mphamvu zofooka za van der Waals zimakhalapo pakati pa mafilimu a graphene/graphite ndi magawo (akhale magawo olimba monga SiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 ndi mafilimu a lacy carbon30, 34 kapena magawo osinthasintha. monga polyimide 37). Apa tikuganiza kuti kuyanjana kwamtundu womwewo kumakhala kopambana. Sitinawone kuwonongeka kapena kupukuta kwa NGF pazigawo zilizonse zomwe zimaperekedwa pano panthawi yogwiritsira ntchito makina (panthawi yodziwika pansi pa vacuum ndi / kapena mlengalenga kapena panthawi yosungirako) (mwachitsanzo, Chithunzi 2, SI7 ndi SI9). Kuonjezera apo, sitinawone nsonga ya SiC mu XPS C 1 s spectrum ya mlingo wapakati wa chitsanzo cha NGF / SiO2 / Si (Mkuyu 4). Zotsatirazi zikuwonetsa kuti palibe mgwirizano wamankhwala pakati pa NGF ndi gawo lapansi lomwe mukufuna.
Mu gawo lapitalo, "Polymer-free transfer of FS- ndi BS-NGF," tidawonetsa kuti NGF ikhoza kukula ndi kusamutsa mbali zonse za nickel zojambulazo. Ma FS-NGF ndi BS-NGF awa sali ofanana potengera kuuma kwapamtunda, zomwe zidatipangitsa kuti tifufuze mapulogalamu oyenera kwambiri pamtundu uliwonse.
Poganizira zowonekera komanso zosalala za FS-NGF, tidaphunzira momwe zimakhalira, mawonekedwe ndi magetsi mwatsatanetsatane. Mapangidwe ndi mawonekedwe a FS-NGF popanda kutengerapo polima adadziwika ndi kujambula kwa ma electron microscopy (TEM) ndi kusanthula kwapadera kwa electron diffraction (SAED). Zotsatira zofananira zikuwonetsedwa mu Chithunzi 5. Kujambula kwa TEM kwapang'onopang'ono kunawonetsa kukhalapo kwa madera a NGF ndi FLG omwe ali ndi makhalidwe osiyana a ma elekitironi, mwachitsanzo, madera akuda ndi owala, motsatira (mkuyu 5a). Kanemayu amawonetsa kukhulupirika kwamakina ndi kukhazikika pakati pa zigawo zosiyanasiyana za NGF ndi FLG, ndikulumikizana bwino komanso kulibe kuwonongeka kapena kung'ambika, zomwe zidatsimikiziridwanso ndi SEM (Chithunzi 3) ndi maphunziro apamwamba a TEM (Chithunzi 5c-e). Makamaka, mu Mkuyu. Chithunzi 5d chimasonyeza dongosolo la mlatho pa gawo lake lalikulu (malo omwe amadziwika ndi muvi wakuda wakuda mu Chithunzi 5d), chomwe chimadziwika ndi mawonekedwe a katatu ndipo chimakhala ndi graphene wosanjikiza ndi m'lifupi mwake pafupifupi 51. Zomwe zili ndi katayanidwe kapakati pa 0.33 ± 0.01 nm zimachepetsedwa kukhala zigawo zingapo za graphene m'chigawo chopapatiza (mapeto a muvi wolimba wakuda mu Chithunzi 5 d).
Chithunzi cha Planar TEM cha chitsanzo cha NiAG chopanda polima pa grid lacy copper: (a, b) Zithunzi za TEM zokulira pang'ono kuphatikiza zigawo za NGF ndi FLG, (ce) Zithunzi zakukweza kwambiri za zigawo zosiyanasiyana mu panel-a ndi gulu-b ndi mivi yamtundu womwewo. Mivi yobiriwira mu mapanelo a ndi c imawonetsa madera ozungulira omwe awonongeka pakulinganiza kwamitengo. (f-i) Mu mapanelo a mpaka c, mawonekedwe a SAED m'magawo osiyanasiyana amawonetsedwa ndi mabwalo abuluu, a cyan, lalanje, ndi ofiira motsatana.
Kapangidwe ka riboni mu Chithunzi 5c ikuwonetsa (yomwe ili ndi muvi wofiyira) kulunjika kwa ndege za graphite lattice, zomwe zingakhale chifukwa cha mapangidwe a nanofolds pamodzi ndi filimuyi (yomwe ili mu Chithunzi 5c) chifukwa cha kumeta ubweya wambiri wosalipidwa30,61,62 . Pansi pa TEM yokhazikika kwambiri, ma nanofolds 30 awa amawonetsa mawonekedwe osiyanasiyana a crystallographic kuposa dera lonse la NGF; ndege zoyambira za graphite lattice zimayendetsedwa molunjika, osati mopingasa ngati filimu yonseyo (chithunzi cha 5c). Mofananamo, dera la FLG nthawi zina limakhala ndi mikwingwirima yopapatiza komanso yopapatiza (yomwe ili ndi mivi yabuluu), yomwe imawonekera pakukweza kotsika komanso kwapakati pazithunzi 5b, 5e, motsatana. Zomwe zili mu Chithunzi 5e zimatsimikizira kukhalapo kwa zigawo ziwiri ndi zitatu za graphene mu gawo la FLG (interplanar mtunda 0.33 ± 0.01 nm), zomwe zikugwirizana bwino ndi zotsatira zathu zam'mbuyo30. Kuphatikiza apo, zithunzi zojambulidwa za SEM za NGF zopanda polima zosamutsidwa pama gridi amkuwa okhala ndi mafilimu a kaboni a lacy (atachita miyeso ya TEM yapamwamba) akuwonetsedwa Chithunzi SI9. Chigawo cha FLG choyimitsidwa bwino (cholembedwa ndi muvi wabuluu) ndi dera losweka pa Chithunzi SI9f. Muvi wa buluu (m'mphepete mwa NGF yotumizidwa) umaperekedwa mwadala kusonyeza kuti dera la FLG likhoza kukana kusamutsa popanda polima. Mwachidule, zithunzizi zimatsimikizira kuti NGF yoyimitsidwa pang'ono (kuphatikiza chigawo cha FLG) imasunga umphumphu wamakina ngakhale atagwira mwamphamvu komanso kukhudzidwa ndi vacuum yayikulu pamiyeso ya TEM ndi SEM (Chithunzi SI9).
Chifukwa cha kutsetsereka kwabwino kwa NGF (onani Chithunzi 5a), sikovuta kuwongolera ma flakes pamodzi ndi [0001] domain axis kusanthula kapangidwe ka SAED. Malingana ndi makulidwe a filimuyo ndi malo ake, madera angapo okondweretsa (mfundo 12) adadziwika chifukwa cha maphunziro a electron diffraction. Pazithunzi 5a-c, zigawo zinayi mwazomwezi zikuwonetsedwa ndikuziyika ndi zozungulira zamitundu (buluu, cyan, lalanje, ndi zofiira). Zithunzi 2 ndi 3 za SAED mode. Zithunzi 5f ndi g zinapezedwa kuchokera ku dera la FLG lomwe likuwonetsedwa mu Zithunzi 5 ndi 5. Monga momwe tawonetsera mu Zithunzi 5b ndi c, motsatira. Ali ndi mawonekedwe a hexagonal ofanana ndi graphene63 yopotoka. Makamaka, Chithunzi 5f chikuwonetsa mapangidwe atatu apamwamba omwe ali ndi kalozera wofanana wa [0001] zone axis, mozunguliridwa ndi 10 ° ndi 20 °, monga momwe zikuwonetsedwera ndi kusagwirizana kwamakona kwa mawiri atatu a (10-10) zowonetsera. Momwemonso, Chithunzi cha 5g chikuwonetsa mawonekedwe awiri owoneka bwino a hexagonal ozunguliridwa ndi 20°. Magulu awiri kapena atatu amtundu wa hexagonal m'chigawo cha FLG amatha kuwuka kuchokera ku magawo atatu a ndege kapena kunja kwa ndege graphene zigawo 33 zozungulira wachibale wina ndi mzake. Mosiyana ndi zimenezi, ma electron diffraction pattern mu Chithunzi 5h, i (mogwirizana ndi dera la NGF lomwe lasonyezedwa mu Chithunzi 5a) limasonyeza chitsanzo chimodzi [0001] chokhala ndi mphamvu yowonjezera yowonjezera, yofanana ndi makulidwe akuluakulu a zinthu. Zitsanzo za SAEDzi zimagwirizana ndi mawonekedwe a graphite wochuluka komanso mawonekedwe apakati kusiyana ndi FLG, monga momwe amachitira ndi index 64. Makhalidwe a crystalline properties a NGF adawonetsa kukhalapo kwa ma crystallites awiri kapena atatu a superimposed graphite (kapena graphene). Chodziwika kwambiri m'chigawo cha FLG ndichakuti ma crystallites ali ndi gawo linalake la misorientation ya ndege kapena kunja kwa ndege. Tinthu tating'onoting'ono ta graphite / zigawo zokhala ndi ngodya zozungulira mkati mwa ndege za 17 °, 22 ° ndi 25 ° zidanenedwapo kale za NGF zomwe zidakula pamafilimu a Ni 64. Miyezo yozungulira yomwe yawonedwa mu phunziroli imagwirizana ndi ma angle ozungulira omwe adawonedwa kale (± 1 °) a graphene ya BLG63 yopindika.
Mphamvu zamagetsi za NGF/SiO2/Si zinayesedwa pa 300 K kudera la 10×3 mm2. Miyezo ya ma elekitironi chonyamulira ndende, kuyenda ndi madutsidwe ndi 1.6 × 1020 cm-3, 220 cm2 V-1 C-1 ndi 2000 S-cm-1, motero. Mayendedwe ndi ma conductivity a NGF yathu ndi ofanana ndi graphite2 yachilengedwe komanso apamwamba kuposa omwe amapezeka pamalonda a pyrolytic graphite (opangidwa pa 3000 ° C) 29. Zomwe zimawonedwa ma elekitironi chonyamulira ndende ndi milingo iwiri ya ukulu kuposa zomwe zanenedwa posachedwapa (7.25 × 10 cm-3) kwa micron-thick graphite mafilimu okonzedwa ndi kutentha kwambiri (3200 °C) polyimide mapepala 20 .
Tidachitanso miyeso yowoneka bwino ya UV pa FS-NGF yosamutsidwa ku magawo a quartz (Chithunzi 6). Zotsatira zake zikuwonetsa kufalikira kosalekeza kwa 62% mumtundu wa 350-800 nm, kuwonetsa kuti NGF imakhala yowoneka bwino. M'malo mwake, dzina loti "KAUST" limatha kuwoneka pazithunzi za digito zachitsanzo mu Chithunzi 6b. Ngakhale kuti mawonekedwe a nanocrystalline a NGF ndi osiyana ndi a SLG, chiwerengero cha zigawo chikhoza kuganiziridwa pogwiritsa ntchito lamulo la 2.3% kutaya kutayika pazitsulo zowonjezera65. Malinga ndi ubalewu, chiwerengero cha zigawo za graphene ndi 38% kutayika kwa kufalitsa ndi 21. NGF yokula makamaka imakhala ndi zigawo za graphene za 300, mwachitsanzo za 100 nm wandiweyani (mkuyu 1, SI5 ndi SI7). Chifukwa chake, timaganiza kuti mawonekedwe owoneka bwino amafanana ndi zigawo za FLG ndi MLG, popeza zimagawidwa mufilimu yonse (Fig. 1, 3, 5 ndi 6c). Kuphatikiza pazidziwitso zapamwambazi, ma conductivity ndi kuwonekera zimatsimikiziranso khalidwe lapamwamba la crystalline la NGF yotumizidwa.
(a) Muyezo wowoneka bwino wa UV, (b) kutumiza kwa NGF pa quartz pogwiritsa ntchito chitsanzo choyimira. (c) Schematic of NGF (dark box) yokhala ndi zigawo za FLG ndi MLG zogawika mofananamo zolembedwa ngati imvi mwachisawawa ponseponse (onani Chithunzi 1) (pafupifupi 0.1-3% dera pa 100 μm2). Maonekedwe osasinthika ndi makulidwe ake pachithunzichi ndi zongowonetsera zokha ndipo sizikugwirizana ndi madera enieni.
Translucent NGF yokulirapo ndi CVD idasamutsidwa m'malo opanda silicon ndikugwiritsidwa ntchito m'maselo a dzuwa15,16. Zotsatira za kutembenuka kwa mphamvu (PCE) ndi 1.5%. Ma NGF awa amachita ntchito zingapo monga zigawo zogwira ntchito, njira zoyendetsera magalimoto, ndi ma electrodes owonekera15,16. Komabe, filimu ya graphite si yofanana. Kukhathamiritsa kwina n'kofunika poyang'anira mosamala kukana kwa pepala ndi kuwala kwa magetsi a graphite electrode, popeza zinthu ziwirizi zimagwira ntchito yofunika kwambiri pozindikira mtengo wa PCE wa solar cell15,16. Kawirikawiri, mafilimu a graphene ndi 97.7% owonekera ku kuwala kowonekera, koma amakhala ndi mapepala otsutsa a 200-3000 ohms / sq.16. Kukaniza pamwamba kwa mafilimu a graphene kungachepe poonjezera chiwerengero cha zigawo (kutengerapo kangapo kwa zigawo za graphene) ndi doping ndi HNO3 (~ 30 Ohm / sq.)66. Komabe, izi zimatenga nthawi yayitali ndipo magawo osiyanasiyana otengerako sakhala olumikizana bwino nthawi zonse. Mbali yathu yakutsogolo NGF ili ndi katundu monga conductivity 2000 S/cm, kukana filimu pepala 50 ohm/sq. ndi 62% kuwonekera, kuzipanga kukhala njira yotheka yopangira njira zopangira kapena ma electrode owerengera m'maselo a dzuwa15,16.
Ngakhale kuti kapangidwe kake ndi kapangidwe kake ka BS-NGF ndi kofanana ndi FS-NGF, kuuma kwake kumasiyana (“Kukula kwa FS- ndi BS-NGF”). M'mbuyomu, tidagwiritsa ntchito filimu yowonda kwambiri ya graphite22 ngati sensa yamagesi. Chifukwa chake, tidayesa kuthekera kogwiritsa ntchito BS-NGF pazinthu zowonera gasi (Chithunzi SI10). Choyamba, magawo a mm2-kakulidwe a BS-NGF adasamutsidwa ku interdigitating electrode sensor chip (Chithunzi SI10a-c). Zambiri zopanga chip zidanenedwa kale; malo ake okhudzidwa ndi 9 mm267. Muzithunzi za SEM (Chithunzi SI10b ndi c), electrode yagolide yomwe ili pansi ikuwonekera bwino kudzera mu NGF. Apanso, zitha kuwoneka kuti kufalikira kwa chip yunifolomu kunapezedwa pa zitsanzo zonse. Miyezo ya sensa ya gasi ya mpweya wosiyanasiyana inalembedwa (mkuyu SI10d) (mkuyu SI11) ndipo zotsatira zomwe zimayankhidwa zikuwonetsedwa muzithunzi. SI10g. Mwinamwake ndi mpweya wina wosokoneza kuphatikizapo SO2 (200 ppm), H2 (2%), CH4 (200 ppm), CO2 (2%), H2S (200 ppm) ndi NH3 (200 ppm). Chifukwa chimodzi chotheka ndi NO2. electrophilic chikhalidwe cha gasi22,68. Pamene adsorbed padziko graphene, amachepetsa mayamwidwe panopa ma elekitironi ndi dongosolo. Kuyerekeza kwa data ya nthawi yoyankha ya sensor ya BS-NGF yokhala ndi masensa omwe adasindikizidwa kale ikuwonetsedwa mu Table SI2. Njira yotsitsimutsanso masensa a NGF pogwiritsa ntchito UV plasma, O3 plasma kapena kutentha (50-150 ° C) chithandizo cha zitsanzo zowonekera chikupitirirabe, ndikutsatiridwa ndi kukhazikitsidwa kwa machitidwe ophatikizidwa69.
Pa CVD ndondomeko, graphene kukula kumachitika mbali zonse za chothandizira gawo lapansi41. Komabe, BS-graphene nthawi zambiri imatulutsidwa panthawi ya kusamutsa41. Mu phunziro ili, tikuwonetsa kuti kukula kwapamwamba kwa NGF ndi kusamutsidwa kwa NGF kopanda polima kumatha kupindula mbali zonse za chithandizo chothandizira. BS-NGF ndi yocheperapo (~ 80 nm) kuposa FS-NGF (~ 100 nm), ndipo kusiyana kumeneku kukufotokozedwa ndi mfundo yakuti BS-Ni sichidziwika mwachindunji ndi kayendedwe ka gasi kalambulabwalo. Tidapezanso kuti kukhwimitsa kwa gawo lapansi la NiAR kumakhudza kukhwimitsa kwa NGF. Zotsatirazi zikuwonetsa kuti planar yokulirapo FS-NGF ingagwiritsidwe ntchito ngati choyambira cha graphene (mwa exfoliation method70) kapena ngati njira yoyendetsera ma cell a solar15,16. Mosiyana ndi zimenezi, BS-NGF idzagwiritsidwa ntchito pozindikira gasi (mkuyu SI9) ndipo mwinamwake kwa machitidwe osungira mphamvu71,72 kumene kuuma kwake kudzakhala kothandiza.
Poganizira zomwe tafotokozazi, ndizothandiza kuphatikiza ntchito zomwe zikuchitika pano ndi mafilimu a graphite omwe adafalitsidwa kale ndi CVD ndikugwiritsa ntchito zojambula za nickel. Monga tikuonera mu Table 2, zipsinjo zapamwamba zomwe tidagwiritsa ntchito zidafupikitsa nthawi yochitira (nthawi yakukula) ngakhale pa kutentha kocheperako (kuyambira 850-1300 ° C). Tinapezanso kukula kwakukulu kuposa masiku onse, kusonyeza kuthekera kwa kukula. Palinso zinthu zina zofunika kuziganizira, zina zomwe taziphatikiza patebulo.
NGF yokhala ndi mbali ziwiri zapamwamba idakulitsidwa pazithunzi za faifi tambala ndi catalytic CVD. Pochotsa magawo amtundu wa polima (monga omwe amagwiritsidwa ntchito mu CVD graphene), timapeza kusamutsa konyowa koyera komanso kopanda chilema kwa NGF (yokula kumbuyo ndi kutsogolo kwa zojambula za faifi tambala) kupita ku magawo osiyanasiyana ofunikira. Makamaka, NGF imaphatikizapo zigawo za FLG ndi MLG (nthawi zambiri 0.1% mpaka 3% pa 100 µm2) zomwe zimaphatikizidwa bwino mufilimu yokhuthala. Planar TEM ikuwonetsa kuti maderawa amapangidwa ndi milu iwiri kapena itatu ya tinthu tating'ono ta graphite/graphene (makhiristo kapena zigawo, motsatana), ena omwe amakhala ndi kusinthasintha kozungulira kwa 10-20 °. Madera a FLG ndi MLG ali ndi udindo wowonetsetsa kuti FS-NGF iwonetsere kuwala kowonekera. Ponena za mapepala akumbuyo, amatha kunyamulidwa mofanana ndi mapepala akutsogolo ndipo, monga momwe akuwonetsera, akhoza kukhala ndi cholinga chogwira ntchito (mwachitsanzo, kufufuza gasi). Maphunzirowa ndiwothandiza kwambiri pakuchepetsa zinyalala komanso mtengo wamakampani a CVD.
Kawirikawiri, makulidwe apakati a CVD NGF ali pakati pa (otsika ndi osanjikiza) graphene ndi mafakitale (micrometer) graphite mapepala. Kusiyanasiyana kwa zinthu zawo zosangalatsa, kuphatikizapo njira yosavuta yomwe tapanga popanga ndi kuyendetsa, imapangitsa mafilimuwa kukhala oyenera kwambiri pa ntchito zomwe zimafuna kuyankha kwa graphite, popanda kuwononga ndalama zopangira mphamvu zamagetsi zomwe zimagwiritsidwa ntchito panopa.
Chojambula cha nickel cha 25-μm (99.5% choyera, Goodfellow) chinayikidwa mu malonda a CVD reactor (Aixtron 4-inch BMPro). Dongosololi lidatsukidwa ndi argon ndikusamutsira ku mphamvu yoyambira ya 10-3 mbar. Kenako zojambula za nickel zidayikidwa. mu Ar / H2 (Pambuyo pokonzekera kale Ni foil kwa 5 min, zojambulazo zinawonetsedwa ndi kupanikizika kwa 500 mbar pa 900 ° C. NGF inayikidwa mumtsinje wa CH4 / H2 (100 cm3 aliyense) kwa 5 min. Chitsanzocho chinakhazikika kutentha pansi pa 700 ° C pogwiritsa ntchito Ar flow (4000 cm3) pa 40 ° C / min Tsatanetsatane wa kukhathamiritsa kwa kukula kwa NGF akufotokozedwa kwina30.
Maonekedwe a pamwamba a chitsanzo adawonetsedwa ndi SEM pogwiritsa ntchito microscope ya Zeiss Merlin (1 kV, 50 pA). Zitsanzo za roughness pamwamba ndi makulidwe a NGF adayesedwa pogwiritsa ntchito AFM (Dimension Icon SPM, Bruker). Kuyeza kwa TEM ndi SAED kunachitika pogwiritsa ntchito microscope ya FEI Titan 80-300 Cubed yokhala ndi mfuti yowala kwambiri (300 kV), FEI Wien monochromator ndi lens ya CEOS lens spherical aberration corrector kuti mupeze zotsatira zomaliza. Kusintha kwa malo 0.09 nm. Zitsanzo za NGF zidasamutsidwa ku ma gridi amkuwa opangidwa ndi kaboni lacy kuti apange chithunzi cha TEM chathyathyathya ndi kusanthula mawonekedwe a SAED. Chifukwa chake, ma flocs ambiri amayimitsidwa pama pores a membrane yothandizira. Zitsanzo zotumizidwa za NGF zidawunikidwa ndi XRD. Ma X-ray diffraction machitidwe adapezedwa pogwiritsa ntchito diffractometer ya ufa (Brucker, D2 phase shifter with Cu Kα source, 1.5418 Å ndi LYNXEYE detector) pogwiritsa ntchito gwero la ma radiation a Cu okhala ndi dothi lozungulira la 3 mm.
Miyezo ingapo ya mfundo za Raman idajambulidwa pogwiritsa ntchito maikulosikopu ophatikizika (Alpha 300 RA, WITeC). Laser ya 532 nm yokhala ndi mphamvu yocheperako (25%) idagwiritsidwa ntchito kupeŵa zotsatira za kutentha. X-ray photoelectron spectroscopy (XPS) inachitidwa pa Kratos Axis Ultra spectrometer pa chitsanzo cha 300 × 700 μm2 pogwiritsa ntchito ma radiation a Al Kα monochromatic (hν = 1486.6 eV) pa mphamvu ya 150 W. Resolution spectra inapezedwa pa mphamvu zotumizira za 160 eV ndi 20 eV, motsatana. Zitsanzo za NGF zomwe zinasamutsidwa ku SiO2 zinadulidwa mu zidutswa (3 × 10 mm2 aliyense) pogwiritsa ntchito PLS6MW (1.06 μm) ytterbium fiber laser pa 30 W. Copper wire contacts (50 μm wandiweyani) anapangidwa pogwiritsa ntchito phala lasiliva pansi pa microscope ya kuwala. Mayendedwe amagetsi ndi Kuyesa kwa Hall effect kunachitika pazitsanzozi pa 300 K ndi kusintha kwa maginito kwa ± 9 Tesla mu dongosolo loyezera katundu (PPMS EverCool-II, Quantum Design, USA). Zowonera za UV-vis zojambulidwa zidajambulidwa pogwiritsa ntchito Lambda 950 UV-vis spectrophotometer mu 350-800 nm NGF osiyanasiyana osamutsidwa ku magawo a quartz ndi zitsanzo za quartz.
Sensor yotsutsa mankhwala (interdigitated electrode chip) idalumikizidwa ku bolodi losindikizidwa losindikizidwa 73 ndipo kukana kudatulutsidwa kwakanthawi. Pulojekiti yosindikizidwa yomwe chipangizocho chilipo chimagwirizanitsidwa ndi malo okhudzana ndi mpweya ndikuyika mkati mwa chipinda chodzidzimutsa mpweya 74. Miyezo ya kukana inatengedwa pamagetsi a 1 V ndi jambulani mosalekeza kuchokera ku purge kupita ku gasi ndikuyeretsanso. Chipindacho poyamba chinatsukidwa ndi kutsukidwa ndi nayitrogeni pa 200 cm3 kwa ola la 1 kuti zitsimikizire kuchotsedwa kwa analytes ena onse omwe ali m'chipindamo, kuphatikizapo chinyezi. Ofufuzawo adatulutsidwa pang'onopang'ono m'chipindamo pamtunda womwewo wa 200 cm3 potseka silinda ya N2.
Nkhani yomwe yasinthidwanso yasindikizidwa ndipo ikupezeka kudzera pa ulalo womwe uli pamwamba pa nkhaniyi.
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Nthawi yotumiza: Aug-23-2024