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ʻO nā kiʻiʻoniʻoni graphite Nanoscale (NGFs) he mau nanomaterials ikaika hiki ke hana ʻia e ka catalytic chemical vapor deposition, akā ke mau nei nā nīnau e pili ana i ko lākou maʻalahi o ka hoʻoili ʻana a pehea e pili ai ke ʻano o ka ʻili i kā lākou hoʻohana ʻana i nā mea hana hanauna hou. Maanei mākou e hōʻike nei i ka ulu ʻana o NGF ma nā ʻaoʻao ʻelua o kahi foil nickel polycrystalline (ʻāpana 55 cm2, mānoanoa ma kahi o 100 nm) a me kāna hoʻoili polymer-free (mua a hope, ʻāpana a hiki i 6 cm2). Ma muli o ke ʻano o ka foil catalyst, ʻokoʻa nā kiʻiʻoniʻoni kalapona ʻelua i ko lākou mau waiwai kino a me nā ʻano ʻē aʻe (e like me ka ʻili ʻino). Hōʻike mākou he kūpono nā NGF me kahi ʻaoʻao hope ʻoi aku ka ʻino no ka ʻike ʻana iā NO2, ʻoiai ʻo nā NGFs palupalu a ʻoi aku ka conductive ma ka ʻaoʻao mua (2000 S/cm, pale pepa - 50 ohms/m2) hiki ke lilo i mau alakaʻi ola. kahawai a i ʻole electrode o ke kelepona solar (ʻoiai e hoʻouna ana i 62% o ka mālamalama ʻike ʻia). Ma keʻano holoʻokoʻa, hiki i nā kaʻina hana ulu a me ka lawe ʻana i wehewehe ʻia ke kōkua i ka hoʻomaopopo ʻana iā NGF ma ke ʻano he mea kalapona ʻē aʻe no nā noi ʻenehana kahi i kūpono ʻole ai nā kiʻiʻoniʻoni graphite graphene a me ka micron-thick.
He mea ʻoihana i hoʻohana nui ʻia ka Graphite. ʻO ka mea nui, loaʻa i ka graphite nā waiwai o ka haʻahaʻa haʻahaʻa o ka nuipa a me ke alakaʻi wela a me ka uila kiʻekiʻe i loko o ka mokulele, a he paʻa loa ia i nā ʻano wela a me nā kemika ʻino1,2. ʻO ka graphite flake kahi mea hoʻomaka kaulana no ka noiʻi graphene3. Ke hana ʻia i loko o nā kiʻiʻoniʻoni lahilahi, hiki ke hoʻohana ʻia i loko o nā ʻano noi like ʻole, me nā poho wela no nā mea uila e like me nā kelepona akamai4,5,6,7, ma ke ʻano he mea hana i nā sensor8,9,10 a no ka pale ʻana i ka hoʻopilikia electromagnetic11.12 a me nā kiʻiʻoniʻoni no ka lithography ma ka ultraviolet koʻikoʻi13,14, nā kahawai alakaʻi i nā cell solar15,16. No kēia mau noi āpau, he pono nui ia inā hiki ke hana maʻalahi ʻia a lawe ʻia nā wahi nui o nā kiʻiʻoniʻoni graphite (NGFs) me nā mānoanoa i kāohi ʻia ma ka nanoscale <100 nm.
Hana ʻia nā kiʻiʻoniʻoni graphite e nā ʻano hana like ʻole. I kekahi hihia, ua hoʻohana ʻia ka hoʻokomo ʻana a me ka hoʻonui ʻana a ukali ʻia e ka exfoliation e hana i nā ʻāpana graphene10,11,17. Pono e hana hou ʻia nā ʻāpana i loko o nā kiʻiʻoniʻoni o ka mānoanoa e pono ai, a pinepine ia he mau lā e hana ai i nā pepa graphite mānoanoa. ʻO kekahi ala ʻē aʻe, ʻo ia ka hoʻomaka ʻana me nā precursors paʻa graphitable. I ka ʻoihana, ua carbonized nā pepa o nā polymers (ma 1000-1500 °C) a laila graphitized (ma 2800-3200 °C) e hana i nā mea papa i hoʻonohonoho pono ʻia. ʻOiai ke kiʻekiʻe o ke ʻano o kēia mau kiʻiʻoniʻoni, he koʻikoʻi ka hoʻohana ʻana i ka ikehu1,18,19 a ua kaupalena ʻia ka mānoanoa liʻiliʻi i kekahi mau microns1,18,19,20.
ʻO ka Catalytic chemical vapor deposition (CVD) kahi ʻano hana kaulana no ka hana ʻana i nā kiʻiʻoniʻoni graphene a me nā kiʻiʻoniʻoni graphite ultrathin (<10 nm) me ke ʻano kūkulu kiʻekiʻe a me ke kumukūʻai kūpono21,22,23,24,25,26,27. Eia nō naʻe, i hoʻohālikelike ʻia me ka ulu ʻana o nā kiʻiʻoniʻoni graphene a me nā kiʻiʻoniʻoni graphite ultrathin28, ʻoi aku ka liʻiliʻi o ka ʻimi ʻia ʻana o ka ulu ʻana o ka wahi nui a/a i ʻole ka hoʻohana ʻana o NGF me ka hoʻohana ʻana iā CVD11,13,29,30,31,32,33.
Pono pinepine e hoʻoili ʻia nā kiʻiʻoniʻoni graphene a me graphite i ulu ʻia e CVD ma luna o nā substrates hana34. Pili kēia mau hoʻoili ʻili lahilahi i ʻelua mau ʻano nui35: (1) ka hoʻoili ʻole ʻana36,37 a me (2) ka hoʻoili kemika pulu e pili ana i ka etch (kākoʻo ʻia ka substrate)14,34,38. Loaʻa i kēlā me kēia ʻano kekahi mau pono a me nā hemahema a pono e koho ʻia ma muli o ka noi i manaʻo ʻia, e like me ka mea i wehewehe ʻia ma kahi ʻē aʻe35,39. No nā kiʻiʻoniʻoni graphene/graphite i ulu ʻia ma nā substrates catalytic, ʻo ka hoʻoili ʻana ma o nā kaʻina hana kemika pulu (ʻo ia ka polymethyl methacrylate (PMMA) ka papa kākoʻo i hoʻohana pinepine ʻia) ke koho mua13,30,34,38,40,41,42. You et al. Ua ʻōlelo ʻia ʻaʻohe polymer i hoʻohana ʻia no ka hoʻoili NGF (ka nui o ka laʻana ma kahi o 4 cm2)25,43, akā ʻaʻohe kikoʻī i hāʻawi ʻia e pili ana i ke kūpaʻa o ka laʻana a/a i ʻole ka lawelawe ʻana i ka wā o ka hoʻoili ʻana; ʻO nā kaʻina hana kemika pulu e hoʻohana ana i nā polymers he mau ʻanuʻu, me ka hoʻopili ʻana a me ka wehe ʻana ma hope o kahi papa polymer mōhai30,38,40,41,42. He mau hemahema kēia kaʻina hana: no ka laʻana, hiki i nā koena polymer ke hoʻololi i nā waiwai o ke kiʻiʻoniʻoni i ulu ʻia38. Hiki i ka hana hou ke wehe i ke koena polymer, akā hoʻonui kēia mau ʻanuʻu hou i ke kumukūʻai a me ka manawa o ka hana ʻana i ke kiʻiʻoniʻoni38,40. I ka wā o ka ulu ʻana o CVD, waiho ʻia kahi papa o graphene ʻaʻole wale ma ka ʻaoʻao mua o ka foil catalyst (ka ʻaoʻao e kū pono ana i ke kahe mahu), akā ma kona ʻaoʻao hope. Eia nō naʻe, ua manaʻo ʻia ka mea hope he huahana ʻōpala a hiki ke wehe koke ʻia e ka plasma palupalu38,41. Hiki i ka hana hou ʻana i kēia kiʻiʻoniʻoni ke kōkua i ka hoʻonui ʻana i ka hua, ʻoiai inā ʻoi aku ka haʻahaʻa o ke ʻano ma mua o ke kiʻiʻoniʻoni kalapona maka.
Maanei, ke hōʻike nei mākou i ka hoʻomākaukau ʻana o ka ulu bifacial wafer-scale o NGF me ke ʻano kūkulu kiʻekiʻe ma ka foil nickel polycrystalline e CVD. Ua loiloi ʻia pehea ka hopena o ka ʻoʻoleʻa o ka ʻili mua a me hope o ka foil i ke ʻano a me ke ʻano o NGF. Hōʻike pū mākou i ka hoʻoili ʻana o NGF me ka uku kūpono a me ke kaiapuni ʻole polymer mai nā ʻaoʻao ʻelua o ka foil nickel ma luna o nā substrates multifunctional a hōʻike pehea e kūpono ai nā kiʻiʻoniʻoni mua a me hope no nā noi like ʻole.
Kūkākūkā nā ʻāpana ma lalo nei i nā mānoanoa like ʻole o ka ʻili graphite ma muli o ka helu o nā papa graphene i hoʻopaʻa ʻia: (i) graphene papa hoʻokahi (SLG, 1 papa), (ii) graphene papa liʻiliʻi (FLG, < 10 papa), (iii) graphene papa he nui (MLG, 10-30 papa) a me (iv) NGF (~300 papa). ʻO ka mea hope ka mānoanoa maʻamau i hōʻike ʻia ma ke ʻano he pakeneka o ka ʻāpana (ma kahi o 97% o ka ʻāpana no 100 µm2)30. ʻO ia ke kumu i kapa wale ʻia ai ka ʻili holoʻokoʻa ʻo NGF.
ʻOkoʻa nā ʻano o nā foil nickel polycrystalline i hoʻohana ʻia no ka hana ʻana o nā kiʻiʻoniʻoni graphene a me graphite ma muli o kā lākou hana ʻana a me ka hana ʻana ma hope. Ua hōʻike koke mākou i kahi noiʻi e hoʻomaikaʻi i ke kaʻina hana ulu o NGF30. Hōʻike mākou he kuleana koʻikoʻi nā ʻano hana e like me ka manawa annealing a me ke kaomi o ke keʻena i ka wā ulu i ka loaʻa ʻana o nā NGF o ka mānoanoa like. Maanei, ua noiʻi hou mākou i ka ulu ʻana o NGF ma nā ʻili polished mua (FS) a me nā ʻili hope i polished ʻole ʻia (BS) o ka foil nickel (Kiʻi 1a). Ua nānā ʻia ʻekolu ʻano o nā laʻana FS a me BS, i helu ʻia ma ka Papa 1. Ma ka nānā ʻana i ka maka, hiki ke ʻike ʻia ka ulu like ʻana o NGF ma nā ʻaoʻao ʻelua o ka foil nickel (NiAG) e ka loli kala o ka substrate Ni nui mai kahi hina kālā metala hiʻohiʻona i kahi kala hina matte (Kiʻi 1a); ua hōʻoia ʻia nā ana microscopic (Kiʻi 1b, c). ʻO kahi spectrum Raman maʻamau o FS-NGF i ʻike ʻia ma ka ʻāpana mālamalama a hōʻike ʻia e nā pua ʻulaʻula, uliuli a me ka ʻalani ma ke Kiʻi 1b e hōʻike ʻia ma ke Kiʻi 1c. ʻO nā piko Raman hiʻona o ka graphite G (1683 cm−1) a me 2D (2696 cm−1) e hōʻoia i ka ulu ʻana o ka NGF crystalline kiʻekiʻe (Kiʻi 1c, Papa SI1). Ma loko o ke kiʻiʻoniʻoni, ua ʻike ʻia ka nui o nā spectra Raman me ka lakio ikaika (I2D/IG) ~0.3, ʻoiai ʻaʻole i ʻike pinepine ʻia nā spectra Raman me I2D/IG = 0.8. ʻO ka loaʻa ʻole o nā piko kīnā (D = 1350 cm-1) ma ke kiʻiʻoniʻoni holoʻokoʻa e hōʻike ana i ke kiʻekiʻe o ka ulu ʻana o NGF. Ua loaʻa nā hopena Raman like ma ka laʻana BS-NGF (Kiʻi SI1 a a me b, Papa SI1).
Hoʻohālikelike o NiAG FS- a me BS-NGF: (a) Kiʻi o kahi laʻana NGF (NiAG) maʻamau e hōʻike ana i ka ulu ʻana o NGF ma ka pae wafer (55 cm2) a me nā laʻana foil BS- a me FS-Ni i loaʻa, (b) Nā Kiʻi FS-NGF/Ni i loaʻa e kahi microscope optical, (c) nā spectra Raman maʻamau i hoʻopaʻa ʻia ma nā kūlana like ʻole ma ka panel b, (d, f) nā kiʻi SEM ma nā hoʻonui like ʻole ma FS-NGF/Ni, (e, g) nā kiʻi SEM ma nā hoʻonui like ʻole Hoʻonohonoho i ka BS -NGF/Ni. Hōʻike ka pua polū i ka ʻāpana FLG, hōʻike ka pua ʻalani i ka ʻāpana MLG (kokoke i ka ʻāpana FLG), hōʻike ka pua ʻulaʻula i ka ʻāpana NGF, a hōʻike ka pua magenta i ka pelu.
ʻOiai ʻo ka ulu ʻana e pili ana i ka mānoanoa o ka substrate mua, ka nui o ke kristal, ke kuhikuhi ʻana, a me nā palena o ka palaoa, ʻo ka hoʻokō ʻana i ka mana kūpono o ka mānoanoa NGF ma luna o nā wahi nui he mea paʻakikī ia20,34,44. Ua hoʻohana kēia haʻawina i ka ʻike a mākou i paʻi mua ai30. Hoʻopuka kēia kaʻina hana i kahi ʻāpana mālamalama o 0.1 a 3% no 100 µm230. Ma nā ʻāpana aʻe, hōʻike mākou i nā hopena no nā ʻano ʻāpana ʻelua. Hōʻike nā kiʻi SEM hoʻonui kiʻekiʻe i ke alo o kekahi mau wahi ʻokoʻa mālamalama ma nā ʻaoʻao ʻelua (Kiʻi 1f,g), e hōʻike ana i ke alo o nā ʻāpana FLG a me MLG30,45. Ua hōʻoia ʻia hoʻi kēia e ka Raman scattering (Kiʻi 1c) a me nā hopena TEM (i kūkākūkā ʻia ma hope ma ka ʻāpana "FS-NGF: ʻano a me nā waiwai"). ʻO nā ʻāpana FLG a me MLG i ʻike ʻia ma nā laʻana FS- a me BS-NGF/Ni (mua a me hope NGF i ulu ʻia ma Ni) ua ulu paha ma nā hua Ni(111) nui i hana ʻia i ka wā o ka pre-annealing22,30,45. Ua ʻike ʻia ka pelu ʻana ma nā ʻaoʻao ʻelua (Kiʻi 1b, i hōʻailona ʻia me nā pua poni). Loaʻa pinepine kēia mau pelu i nā kiʻiʻoniʻoni graphene a me graphite i ulu ʻia e CVD ma muli o ka ʻokoʻa nui o ke coefficient o ka hoʻonui wela ma waena o ka graphite a me ka substrate nickel30,38.
Ua hōʻoia ke kiʻi AFM ua ʻoi aku ka palahalaha o ka hāpana FS-NGF ma mua o ka hāpana BS-NGF (Kiʻi SI1) (Kiʻi SI2). ʻO nā waiwai ʻoʻoleʻa kumu awelika (RMS) o FS-NGF/Ni (Kiʻi SI2c) a me BS-NGF/Ni (Kiʻi SI2d) he 82 a me 200 nm, kēlā me kēia (i ana ʻia ma luna o kahi ʻāpana o 20 × 20 μm2). Hiki ke hoʻomaopopo ʻia ka ʻoʻoleʻa kiʻekiʻe ma muli o ka nānā ʻana o ka ʻili o ka foil nickel (NiAR) i ke kūlana i loaʻa (Kiʻi SI3). Hōʻike ʻia nā kiʻi SEM o FS a me BS-NiAR ma nā Kiʻi SI3a–d, e hōʻike ana i nā ʻano ʻili like ʻole: he nano- a me micron-sized nā ʻāpana poepoe o ka foil FS-Ni i poli ʻia, ʻoiai ʻo ka foil BS-Ni i poli ʻole ʻia e hōʻike ana i kahi alapiʻi hana. e like me nā ʻāpana me ka ikaika kiʻekiʻe. a me ka emi ʻana. Hōʻike ʻia nā kiʻi haʻahaʻa a kiʻekiʻe o ka foil nickel annealed (NiA) ma ke Kiʻi SI3e–h. Ma kēia mau kiʻi, hiki iā mākou ke nānā i ke alo o kekahi mau ʻāpana nickel nui micron ma nā ʻaoʻao ʻelua o ka pepa nickel (Kiʻi SI3e-h). Hiki i nā hua nui ke loaʻa kahi ʻano ʻili Ni(111), e like me ka mea i hōʻike mua ʻia30,46. Aia nā ʻokoʻa koʻikoʻi i ke ʻano o ka pepa nickel ma waena o FS-NiA a me BS-NiA. ʻO ke kiʻekiʻe o ka ʻoʻoleʻa o BS-NGF/Ni ma muli o ka ʻili i wili ʻole ʻia o BS-NiAR, nona ka ʻili e mau ana ka ʻoʻoleʻa ma hope o ka annealing (Kiʻi SI3). ʻO kēia ʻano ʻano ʻili ma mua o ke kaʻina hana ulu e hiki ai ke kāohi i ka ʻoʻoleʻa o nā kiʻiʻoniʻoni graphene a me graphite. Pono e hoʻomaopopo ʻia ua hana hou ʻia ka substrate mua i ka wā o ka ulu ʻana o graphene, kahi i hoʻemi iki i ka nui o ka hua a hoʻonui iki i ka ʻoʻoleʻa o ka ʻili o ka substrate i hoʻohālikelike ʻia me ka pepa annealed a me ka pepa catalyst22.
ʻO ka hoʻoponopono maikaʻi ʻana i ka ʻoʻoleʻa o ka substrate, ka manawa annealing (ka nui o ka palaoa)30,47 a me ka hoʻokuʻu ʻana i ka mana43 e kōkua i ka hōʻemi ʻana i ka like ʻana o ka mānoanoa NGF ʻāpana i ka µm2 a/a i ʻole ka unahi nm2 (ʻo ia hoʻi, nā ʻokoʻa mānoanoa o kekahi mau nanometer). No ka hoʻomalu ʻana i ka ʻoʻoleʻa o ka substrate, hiki ke noʻonoʻo ʻia nā ʻano hana e like me ka polishing electrolytic o ka pepa nickel hopena48. A laila hiki ke annealed ʻia ka pepa nickel i mālama mua ʻia ma kahi mahana haʻahaʻa (< 900 °C)46 a me ka manawa (< 5 min) e pale aku i ka hoʻokumu ʻia ʻana o nā hua Ni(111) nui (he mea maikaʻi ia no ka ulu ʻana o FLG).
ʻAʻole hiki i ka SLG a me ka FLG graphene ke kū i ke kaomi ʻili o nā waikawa a me ka wai, e koi ana i nā papa kākoʻo mechanical i ka wā o nā kaʻina hana hoʻoili kemika pulu22,34,38. I ka hoʻohālikelike ʻana i ka hoʻoili kemika pulu o ka polymer-supported single-layer graphene38, ua ʻike mākou hiki ke hoʻoili ʻia nā ʻaoʻao ʻelua o ka NGF i ulu ʻia me ke kākoʻo ʻole o ka polymer, e like me ka mea i hōʻike ʻia ma ke Kiʻi 2a (e nānā i ke Kiʻi SI4a no nā kikoʻī hou aku). Hoʻomaka ka hoʻoili ʻana o NGF i kahi substrate i hāʻawi ʻia me ka etching pulu o ka ʻili Ni30.49 ma lalo. Ua waiho ʻia nā laʻana NGF/Ni/NGF i ulu ʻia i ka pō i loko o 15 mL o 70% HNO3 i hoʻoheheʻe ʻia me 600 mL o ka wai deionized (DI). Ma hope o ka hoʻoheheʻe loa ʻia ʻana o ka pepa Ni, noho palahalaha ʻo FS-NGF a lana ma luna o ka ʻili o ka wai, e like me ka laʻana NGF/Ni/NGF, ʻoiai ua hoʻokomo ʻia ʻo BS-NGF i loko o ka wai (Kiʻi 2a,b). A laila ua hoʻoili ʻia ka NGF i hoʻokaʻawale ʻia mai kekahi kīʻaha me ka wai deionized hou i kekahi kīʻaha ʻē aʻe a ua holoi pono ʻia ka NGF i hoʻokaʻawale ʻia, e hana hou ana i ʻehā a ʻeono manawa ma o ke kīʻaha aniani concave. ʻO ka hope loa, ua kau ʻia ʻo FS-NGF a me BS-NGF ma luna o ka substrate i makemake ʻia (Kiʻi 2c).
Ke kaʻina hana hoʻoili kemika pulu ʻole-polymer no ka NGF i ulu ʻia ma ka pepa nickel: (a) Kiʻikuhi kahe o ke kaʻina hana (e nānā i ke Kiʻi SI4 no nā kikoʻī hou aku), (b) Kiʻi kikohoʻe o ka NGF i hoʻokaʻawale ʻia ma hope o ke kālai ʻana o Ni (2 mau laʻana), (c) Hoʻoili laʻana FS - a me BS-NGF i ka substrate SiO2/Si, (d) Hoʻoili FS-NGF i ka substrate polymer opaque, (e) BS-NGF mai ka laʻana like me ka panel d (i māhele ʻia i ʻelua ʻāpana), i hoʻoili ʻia i ka pepa C i uhi ʻia i ke gula a me Nafion (substrate moakaka palupalu, nā kihi i hōʻailona ʻia me nā kihi ʻulaʻula).
E hoʻomaopopo he pono ka manawa hana holoʻokoʻa o 20-24 mau hola no ka hoʻoili ʻana o SLG me ka hoʻohana ʻana i nā ʻano hoʻoili kemika pulu 38. Me ke ʻano hoʻoili polymer-free i hōʻike ʻia ma ʻaneʻi (Kiʻi SI4a), ua hoʻemi nui ʻia ka manawa hana hoʻoili NGF holoʻokoʻa (ma kahi o 15 mau hola). Aia ke kaʻina hana penei: (KaʻAnuʻu Hana 1) E hoʻomākaukau i kahi hopena etching a kau i ka laʻana i loko (~10 mau minuke), a laila e kali i ka pō no ka etching Ni (~7200 mau minuke), (KaʻAnuʻu Hana 2) E holoi me ka wai deionized (KaʻAnuʻu Hana 3). e mālama i loko o ka wai deionized a i ʻole e hoʻoili i ka substrate target (20 min). Hoʻoneʻe ʻia ka wai i paʻa ma waena o ka NGF a me ka matrix bulk e ka hana capillary (me ka hoʻohana ʻana i ka pepa blotting) 38, a laila hoʻoneʻe ʻia nā kulu wai i koe e ka maloʻo kūlohelohe (ma kahi o 30 min), a ʻo ka hope loa ua hoʻomaloʻo ʻia ka laʻana no 10 min. min i loko o ka umu vacuum (10-1 mbar) ma 50-90 °C (60 min) 38.
Ua ʻike ʻia ka Graphite e kū i ke alo o ka wai a me ka ea ma nā mahana kiʻekiʻe (≥ 200 °C)50,51,52. Ua hoʻāʻo mākou i nā laʻana me ka hoʻohana ʻana i ka spectroscopy Raman, SEM, a me XRD ma hope o ka mālama ʻana i loko o ka wai deionized ma ka mahana o ka lumi a i loko o nā ʻōmole i hoʻopaʻa ʻia no kekahi mau lā a i hoʻokahi makahiki (Kiʻi SI4). ʻAʻohe hōʻino ʻike ʻia. Hōʻike ka Kiʻi 2c i ka FS-NGF kūʻokoʻa a me BS-NGF i loko o ka wai deionized. Ua hopu mākou iā lākou ma kahi substrate SiO2 (300 nm)/Si, e like me ka mea i hōʻike ʻia ma ka hoʻomaka ʻana o ke Kiʻi 2c. Eia kekahi, e like me ka mea i hōʻike ʻia ma ke Kiʻi 2d,e, hiki ke hoʻoili ʻia ka NGF hoʻomau i nā substrates like ʻole e like me nā polymers (Thermabright polyamide mai Nexolve lāua ʻo Nafion) a me ka pepa kalapona i uhi ʻia i ke gula. Ua maʻalahi ka waiho ʻana o ka FS-NGF lana ma luna o ka substrate target (Kiʻi 2c, d). Eia naʻe, ua paʻakikī ke lawelawe ʻana i nā laʻana BS-NGF ʻoi aku ka nui ma mua o 3 cm2 i ka wā e hoʻokomo piha ʻia ai i loko o ka wai. ʻO ka maʻamau, ke hoʻomaka lākou e ʻōwili i ka wai, ma muli o ka mālama pono ʻole ʻana, ua haki lākou i ʻelua a ʻekolu paha ʻāpana (Kiʻi 2e). Ma ke ʻano holoʻokoʻa, ua hiki iā mākou ke hoʻokō i ka hoʻoili ʻole polymer o PS- a me BS-NGF (hoʻoili mau ʻole me ka ʻole o ka ulu ʻana o NGF/Ni/NGF ma 6 cm2) no nā laʻana a hiki i ka 6 a me 3 cm2 i ka wahi, kēlā me kēia. Hiki ke hoʻohana ʻia nā ʻāpana nui a liʻiliʻi paha i koe (ʻike maʻalahi ʻia i loko o ka hopena etching a i ʻole ka wai deionized) ma ka substrate i makemake ʻia (~1 mm2, Kiʻi SI4b, e ʻike i ka laʻana i hoʻoili ʻia i ka grid keleawe e like me "FS-NGF: Structure and Properties (discussed) ma lalo o "Structure and Properties") a mālama ʻia no ka hoʻohana ʻana i ka wā e hiki mai ana (Kiʻi SI4). Ma muli o kēia pae hoʻohālikelike, manaʻo mākou e hiki ke hoʻihoʻi ʻia ʻo NGF i nā hua a hiki i ka 98-99% (ma hope o ka ulu ʻana no ka hoʻoili ʻana).
Ua kālailai ʻia nā laʻana hoʻoili me ka ʻole o ka polymer ma ke kikoʻī. Ua hōʻike ʻia nā ʻano morphological o ka ʻili i loaʻa ma FS- a me BS-NGF/SiO2/Si (Kiʻi 2c) me ka hoʻohana ʻana i ka microscopy optical (OM) a me nā kiʻi SEM (Kiʻi SI5 a me Fig. 3) ua hoʻoili ʻia kēia mau laʻana me ka ʻole o ka microscopy. ʻIke ʻia ka pōʻino kūkulu e like me nā māwae, nā lua, a i ʻole nā wahi i wehe ʻia. Ua noho paʻa nā pelu ma ka NGF e ulu ana (Kiʻi 3b, d, i hōʻailona ʻia e nā pua poni) ma hope o ka hoʻoili ʻana. Ua haku ʻia nā FS- a me BS-NGF me nā ʻāpana FLG (nā ʻāpana ʻālohilohi i hōʻike ʻia e nā pua polū ma ke Kiʻi 3). ʻO ka mea kupanaha, i ka hoʻohālikelike ʻana i nā ʻāpana i hōʻino ʻia i ʻike pinepine ʻia i ka wā o ka hoʻoili polymer o nā kiʻiʻoniʻoni graphite ultrathin, ua hoʻoili ʻia kekahi mau ʻāpana FLG a me MLG micron-sized e pili ana i ka NGF (i hōʻailona ʻia e nā pua polū ma ke Kiʻi 3d) me ka ʻole o nā māwae a haki paha (Kiʻi 3d). 3). Ua hōʻoia hou ʻia ka pono mechanical me ka hoʻohana ʻana i nā kiʻi TEM a me SEM o NGF i hoʻoili ʻia ma luna o nā grids keleawe lace-carbon, e like me ka mea i kūkākūkā ʻia ma hope ("FS-NGF: Structure and Properties"). ʻOi aku ka ʻino o ka BS-NGF/SiO2/Si i hoʻoili ʻia ma mua o ka FS-NGF/SiO2/Si me nā waiwai rms o 140 nm a me 17 nm, e like me ka mea i hōʻike ʻia ma ke Kiʻi SI6a a me b (20 × 20 μm2). ʻOi aku ka haʻahaʻa o ka waiwai RMS o NGF i hoʻoili ʻia ma luna o ka substrate SiO2/Si (RMS < 2 nm) (ma kahi o 3 mau manawa) ma mua o ka NGF i ulu ʻia ma Ni (Kiʻi SI2), e hōʻike ana e pili ana paha ka ʻino hou i ka ʻili Ni. Eia kekahi, ua hōʻike nā kiʻi AFM i hana ʻia ma nā kihi o nā laʻana FS- a me BS-NGF/SiO2/Si i nā mānoanoa NGF o 100 a me 80 nm, (Kiʻi SI7). ʻO ka mānoanoa liʻiliʻi o ka BS-NGF he hopena paha ia o ka ʻili i hōʻike ʻole ʻia i ke kinoea mua.
ʻO NGF i hoʻoili ʻia (NiAG) me ka ʻole o ka polymer ma ka wafer SiO2/Si (e nānā i ke Kiʻi 2c): (a,b) Nā kiʻi SEM o ka FS-NGF i hoʻoili ʻia: hoʻonui haʻahaʻa a kiʻekiʻe (e pili ana i ka huinahā ʻalani ma ka panela). Nā wahi maʻamau) - a). (c,d) Nā kiʻi SEM o ka BS-NGF i hoʻoili ʻia: hoʻonui haʻahaʻa a kiʻekiʻe (e pili ana i ka wahi maʻamau i hōʻike ʻia e ka huinahā ʻalani ma ka panela c). (e, f) Nā kiʻi AFM o nā FS- a me BS-NGF i hoʻoili ʻia. Hōʻike ka pua polū i ka ʻāpana FLG - ʻokoʻa mālamalama, pua cyan - ʻokoʻa ʻeleʻele MLG, pua ʻulaʻula - ʻokoʻa ʻeleʻele e hōʻike ana i ka ʻāpana NGF, hōʻike ka pua magenta i ka pelu.
Ua kālailai ʻia ke ʻano kemika o nā FS- a me BS-NGF i ulu a hoʻoili ʻia e ka X-ray photoelectron spectroscopy (XPS) (Kiʻi 4). Ua ʻike ʻia kahi piko nāwaliwali i nā spectra i ana ʻia (Kiʻi 4a, b), e pili ana i ka substrate Ni (850 eV) o nā FS- a me BS-NGF i ulu ʻia (NiAG). ʻAʻohe piko i nā spectra i ana ʻia o nā FS- a me BS-NGF/SiO2/Si i hoʻoili ʻia (Kiʻi 4c; ʻaʻole i hōʻike ʻia nā hopena like no BS-NGF/SiO2/Si), e hōʻike ana ʻaʻohe haumia Ni koena ma hope o ka hoʻoili ʻana. Hōʻike nā Kiʻi 4d–f i nā spectra hoʻonā kiʻekiʻe o nā pae ikehu C1s, O1s a me Si2p o FS-NGF/SiO2/Si. ʻO ka ikehu hoʻopaʻa o C1s o ka graphite he 284.4 eV53.54. ʻO ke ʻano linear o nā piko graphite i manaʻo ʻia he asymmetrical, e like me ka mea i hōʻike ʻia ma ke Kiʻi 4d54. Ua hōʻoia pū ka spectrum C1s kiʻekiʻe-resolution core-level (Kiʻi 4d) i ka hoʻoili maʻemaʻe (ʻo ia hoʻi, ʻaʻohe koena polymer), kahi e kūlike me nā haʻawina mua38. ʻO nā linewidths o nā spectra C1s o ka laʻana i ulu hou ʻia (NiAG) a ma hope o ka hoʻoili ʻana he 0.55 a me 0.62 eV, kēlā me kēia. ʻOi aku ke kiʻekiʻe o kēia mau waiwai ma mua o nā SLG (0.49 eV no SLG ma kahi substrate SiO2)38. Eia nō naʻe, ʻoi aku ka liʻiliʻi o kēia mau waiwai ma mua o nā linewidths i hōʻike mua ʻia no nā laʻana graphene pyrolytic i kuhikuhi nui ʻia (~0.75 eV)53,54,55, e hōʻike ana i ka ʻole o nā wahi kalapona hemahema i loko o ka mea o kēia manawa. ʻAʻohe poʻohiwi o nā spectra pae honua C1s a me O1s, e hoʻopau ana i ka pono no ka deconvolution piko kiʻekiʻe-resolution54. Aia kahi piko ukali π → π* ma kahi o 291.1 eV, kahi i ʻike pinepine ʻia i nā laʻana graphite. ʻO nā hōʻailona 103 eV a me 532.5 eV i loko o nā spectra pae kumu Si 2p a me O 1 s (e nānā i ke Kiʻi 4e, f) ua pili i ka substrate SiO2 56, kēlā me kēia. He ʻenehana ʻili koʻikoʻi ʻo XPS, no laila ua manaʻo ʻia nā hōʻailona e pili ana iā Ni a me SiO2 i ʻike ʻia ma mua a ma hope o ka hoʻoili ʻana o NGF, kēlā me kēia, e puka mai ana mai ka ʻāpana FLG. Ua ʻike ʻia nā hopena like no nā laʻana BS-NGF i hoʻoili ʻia (ʻaʻole i hōʻike ʻia).
Nā hopena NiAG XPS: (ac) Nā spectra noiʻi o nā ʻano haku mele atomika like ʻole o FS-NGF/Ni i ulu ʻia, BS-NGF/Ni a me FS-NGF/SiO2/Si i hoʻoili ʻia, kēlā me kēia. (d–f) Nā spectra hoʻonā kiʻekiʻe o nā pae kumu C 1 s, O 1s a me Si 2p o ka hāpana FS-NGF/SiO2/Si.
Ua loiloi ʻia ke ʻano holoʻokoʻa o nā kristal NGF i hoʻoili ʻia me ka hoʻohana ʻana i ka diffraction X-ray (XRD). Hōʻike nā ʻano XRD maʻamau (Fig. SI8) o nā FS- a me BS-NGF/SiO2/Si i hoʻoili ʻia i ke alo o nā piko diffraction (0 0 0 2) a me (0 0 0 4) ma 26.6° a me 54.7°, e like me ka graphite. . Hōʻoia kēia i ke ʻano crystalline kiʻekiʻe o NGF a kūlike me ka mamao interlayer o d = 0.335 nm, i mālama ʻia ma hope o ke kaʻina hoʻoili. ʻO ka ikaika o ka piko diffraction (0 0 0 2) ma kahi o 30 mau manawa o ka piko diffraction (0 0 0 4), e hōʻike ana ua kūlike maikaʻi ka mokulele kristal NGF me ka ʻili o ka laʻana.
Wahi a nā hopena o SEM, Raman spectroscopy, XPS a me XRD, ua ʻike ʻia ke ʻano o BS-NGF/Ni e like me ko FS-NGF/Ni, ʻoiai ua kiʻekiʻe iki kona rms roughness (Kiʻi SI2, SI5) a me SI7).
Hiki i nā SLG me nā papa kākoʻo polymer a hiki i ka 200 nm ka mānoanoa ke lana ma luna o ka wai. Hoʻohana pinepine ʻia kēia hoʻonohonoho ʻana i nā kaʻina hana hoʻoili kemika pulu i kōkua ʻia e ka polymer22,38. He hydrophobic ka Graphene a me ka graphite (kihi pulu 80-90°)57. Ua hōʻike ʻia nā ʻili ikehu hiki o ka graphene a me FLG he pālahalaha loa, me ka ikehu hiki haʻahaʻa (~1 kJ/mol) no ka neʻe ʻana o ka wai ma ka ʻili58. Eia nō naʻe, ʻo nā ikehu pilina i helu ʻia o ka wai me ka graphene a me ʻekolu mau papa o ka graphene ma kahi o − 13 a me − 15 kJ/mol,58 kēlā me kēia, e hōʻike ana he haʻahaʻa ka pilina o ka wai me NGF (ma kahi o 300 mau papa) i hoʻohālikelike ʻia me ka graphene. ʻO kēia paha kekahi o nā kumu e noho pālahalaha ai ka NGF kūʻokoʻa ma luna o ka wai, ʻoiai ʻo ka graphene kūʻokoʻa (e lana ana i ka wai) e ʻōwili a haki. Ke hoʻokomo piha ʻia ʻo NGF i loko o ka wai (like nā hopena no ka NGF ʻino a me ka pālahalaha), kūlou kona mau ʻaoʻao (Kiʻi SI4). I ke ʻano o ka hoʻokomo piha ʻana, ua manaʻo ʻia e aneane pālua ka ikehu pilina NGF-wai (hoʻohālikelike ʻia me ka NGF lana) a e pelu nā kihi o ka NGF e mālama i kahi kihi pili kiʻekiʻe (hydrophobicity). Manaʻo mākou e hiki ke hoʻomohala ʻia nā hoʻolālā e pale aku i ka wili ʻana o nā kihi o nā NGF i hoʻokomo ʻia. ʻO kekahi ala e hoʻohana ai i nā mea hoʻoheheʻe i hui ʻia e hoʻololi i ka hopena pulu o ka ʻili graphite59.
Ua hōʻike mua ʻia ka hoʻoili ʻana o SLG i nā ʻano substrates like ʻole ma o nā kaʻina hana hoʻoili kemika pulu. Ua ʻae ʻia ma ke ʻano laulā he mau mana van der Waals nāwaliwali ma waena o nā kiʻiʻoniʻoni graphene/graphite a me nā substrates (inā he mau substrates paʻa e like me SiO2/Si38,41,46,60, SiC38, Au42, Si pillars22 a me nā kiʻiʻoniʻoni kalapona lacy30, 34 a i ʻole nā substrates palupalu e like me polyimide 37). Maanei mākou e manaʻo nei he nui nā pilina o ke ʻano like. ʻAʻole mākou i ʻike i kekahi pōʻino a i ʻole ka ʻili ʻana o NGF no kekahi o nā substrates i hōʻike ʻia ma ʻaneʻi i ka wā o ka lawelawe ʻana i ka mīkini (i ka wā o ke ʻano ma lalo o ka vacuum a/a i ʻole nā kūlana lewa a i ʻole i ka wā e mālama ai) (e laʻa, Kiʻi 2, SI7 a me SI9). Eia kekahi, ʻaʻole mākou i ʻike i kahi piko SiC ma ka XPS C 1 s spectrum o ka pae kumu o ka laʻana NGF/SiO2/Si (Kiʻi 4). Hōʻike kēia mau hopena ʻaʻohe pilina kemika ma waena o NGF a me ka substrate i manaʻo ʻia.
Ma ka ʻāpana ma mua, "Polymer-free transfer of FS- and BS-NGF," ua hōʻike mākou hiki i ka NGF ke ulu a hoʻoili ma nā ʻaoʻao ʻelua o ka pepa nickel. ʻAʻole like kēia mau FS-NGF a me BS-NGF ma ke ʻano o ka ʻili ʻino, kahi i hoʻoikaika ai iā mākou e ʻimi i nā noi kūpono loa no kēlā me kēia ʻano.
Ma ka noʻonoʻo ʻana i ka moakāka a me ka ʻili laumania o FS-NGF, ua aʻo mākou i kona ʻano kūloko, nā waiwai optical a me nā uila me nā kikoʻī hou aku. Ua hōʻike ʻia ke ʻano a me ke ʻano o FS-NGF me ka ʻole o ka hoʻoili polymer e ke kiʻi microscopy electron transmission (TEM) a me ka nānā ʻana i ke ʻano electron diffraction (SAED) i koho ʻia. Hōʻike ʻia nā hopena pili ma ke Kiʻi 5. Ua hōʻike ka kiʻi TEM planar hoʻonui haʻahaʻa i ke alo o nā ʻāpana NGF a me FLG me nā ʻano ʻokoʻa electron like ʻole, ʻo ia hoʻi nā wahi ʻeleʻele a me nā wahi mālamalama, kēlā me kēia (Kiʻi 5a). Hōʻike ka kiʻiʻoniʻoni holoʻokoʻa i ka pono mechanical maikaʻi a me ke kūpaʻa ma waena o nā ʻāpana like ʻole o NGF a me FLG, me ka overlap maikaʻi a ʻaʻohe hōʻino a haehae paha, i hōʻoia ʻia hoʻi e SEM (Kiʻi 3) a me nā haʻawina TEM hoʻonui kiʻekiʻe (Kiʻi 5c-e). Ma ke ʻano kūikawā, ma ke Kiʻi 5d e hōʻike ana i ke ʻano o ke alahaka ma kona ʻāpana nui loa (ke kūlana i hōʻailona ʻia e ka pua kiko ʻeleʻele ma ke Kiʻi 5d), i hōʻike ʻia e ke ʻano triangular a he papa graphene me ka laulā o kahi 51. Ua hoʻemi hou ʻia ka haku mele me kahi mamao interplanar o 0.33 ± 0.01 nm i kekahi mau papa o ka graphene ma ka ʻāpana haiki loa (ka hopena o ka pua ʻeleʻele paʻa ma ke Kiʻi 5 d).
ʻO ke kiʻi TEM planar o kahi hāpana NiAG ʻole polymer ma kahi grid keleawe kalapona lacy: (a, b) Nā kiʻi TEM hoʻonui haʻahaʻa e komo pū ana me nā ʻāpana NGF a me FLG, (ce) ʻO nā kiʻi hoʻonui kiʻekiʻe o nā ʻāpana like ʻole ma ka panel-a a me ka panel-b he mau pua i hōʻailona ʻia o ke kala like. ʻO nā pua ʻōmaʻomaʻo ma nā panel a a me c e hōʻike ana i nā wahi pōʻai o ka hōʻino ʻia i ka wā o ke kaulike ʻana o ke kukuna. (f–i) Ma nā panel a a i c, ua hōʻike ʻia nā hiʻohiʻona SAED ma nā ʻāpana like ʻole e nā pōʻai polū, cyan, ʻalani, a me ka ʻulaʻula.
ʻO ke ʻano o ka lipine ma ke Kiʻi 5c e hōʻike ana (i hōʻailona ʻia me ka pua ʻulaʻula) i ke kuhikuhi kū pololei o nā mokulele lattice graphite, kahi paha ma muli o ke kūkulu ʻia ʻana o nā nanofolds ma ke kiʻiʻoniʻoni (inset ma ke Kiʻi 5c) ma muli o ke kaumaha shear uncompensated keu 30,61,62. Ma lalo o ka TEM hoʻonā kiʻekiʻe, hōʻike kēia mau nanofolds 30 i kahi kuhikuhi crystallographic ʻokoʻa ma mua o ke koena o ka ʻāpana NGF; ua kuhikuhi ʻia nā mokulele basal o ka lattice graphite kokoke i ke kū pololei, ma mua o ke koena o ke kiʻiʻoniʻoni (inset ma ke Kiʻi 5c). Pēlā nō, hōʻike pinepine ka ʻāpana FLG i nā pelu e like me ke kaula linear a me ka haiki (i hōʻailona ʻia e nā pua polū), e ʻike ʻia ma ka hoʻonui haʻahaʻa a me ka waena ma nā Kiʻi 5b, 5e, kēlā me kēia. Hōʻoia ka inset ma ke Kiʻi 5e i ke alo o nā papa graphene ʻelua a me ʻekolu papa ma ka ʻāpana FLG (mamao interplanar 0.33 ± 0.01 nm), kahi e kūlike maikaʻi me kā mākou mau hopena ma mua 30. Eia kekahi, ua hōʻike ʻia nā kiʻi SEM i hoʻopaʻa ʻia o ka NGF polymer-free i hoʻoili ʻia ma luna o nā grids keleawe me nā kiʻiʻoniʻoni kalapona lacy (ma hope o ka hana ʻana i nā ana TEM top-view) ma ke Kiʻi SI9. ʻO ka ʻāpana FLG i hoʻokuʻu maikaʻi ʻia (i hōʻailona ʻia me ka pua polū) a me ka ʻāpana i haki ʻia ma ke Kiʻi SI9f. Ua hōʻike ʻia ka pua polū (ma ka lihi o ka NGF i hoʻoili ʻia) e hōʻike i ka hiki i ka ʻāpana FLG ke kūʻē i ke kaʻina hana hoʻoili me ka ʻole o ka polymer. I ka hōʻuluʻulu manaʻo, ua hōʻoia kēia mau kiʻi e mālama ana ka NGF i hoʻokuʻu hapa ʻia (me ka ʻāpana FLG) i ka pono mechanical ʻoiai ma hope o ka lawelawe koʻikoʻi a me ka hōʻike ʻana i ka vacuum kiʻekiʻe i ka wā o nā ana TEM a me SEM (Kiʻi SI9).
Ma muli o ke ʻano pālahalaha maikaʻi loa o NGF (e nānā i ke Kiʻi 5a), ʻaʻole paʻakikī ke kuhikuhi i nā ʻāpana ma ke axis kikowaena [0001] e kālailai i ka ʻano SAED. Ma muli o ka mānoanoa kūloko o ke kiʻiʻoniʻoni a me kona wahi, ua ʻike ʻia kekahi mau wahi hoihoi (12 mau helu) no nā haʻawina diffraction electron. Ma nā Kiʻi 5a-c, ua hōʻike ʻia ʻehā o kēia mau wahi maʻamau a ua hōʻailona ʻia me nā pōʻai kala (uliuli, cyan, ʻalani, a me ka ʻulaʻula i code ʻia). Nā Kiʻi 2 a me 3 no ke ʻano SAED. Ua loaʻa nā Kiʻi 5f a me g mai ka ʻāpana FLG i hōʻike ʻia ma nā Kiʻi 5 a me 5. E like me ka mea i hōʻike ʻia ma nā Kiʻi 5b a me c, kēlā me kēia. Loaʻa iā lākou kahi ʻano hexagonal e like me ka graphene twisted63. Ma ke ʻano kūikawā, hōʻike ʻo Kiʻi 5f i ʻekolu mau ʻano i hoʻopili ʻia me ke kuhikuhi like o ka axis zone [0001], i hoʻohuli ʻia e 10° a me 20°, e like me ka hōʻike ʻana e ka mismatch angular o nā hui ʻekolu o (10-10) reflections. Pēlā nō, hōʻike ka Kiʻi 5g i ʻelua mau hiʻohiʻona hexagonal i hoʻopili ʻia i hoʻohuli ʻia e 20°. Hiki i ʻelua a ʻekolu paha mau hui o nā hiʻohiʻona hexagonal ma ka ʻāpana FLG ke kū mai mai ʻekolu mau papa graphene in-plane a i ʻole out-of-plane 33 i hoʻohuli ʻia e pili ana kekahi i kekahi. I ka hoʻohālikelike ʻana, hōʻike nā hiʻohiʻona diffraction electron ma ka Kiʻi 5h,i (e pili ana i ka ʻāpana NGF i hōʻike ʻia ma ke Kiʻi 5a) i hoʻokahi hiʻohiʻona [0001] me ka ikaika diffraction kiko kiʻekiʻe loa, e pili ana i ka mānoanoa o nā mea. Pili kēia mau hiʻohiʻona SAED i kahi ʻano graphitic mānoanoa a me ka orientation waena ma mua o FLG, e like me ka mea i manaʻo ʻia mai ka index 64. Ua hōʻike ka wehewehe ʻana i nā waiwai crystalline o NGF i ka noho pū ʻana o ʻelua a ʻekolu paha mau crystallite graphite (a i ʻole graphene) i hoʻopili ʻia. ʻO ka mea i ʻike nui ʻia ma ka ʻāpana FLG, ʻo ia ka loaʻa ʻana o nā crystallites i kahi kekelē o ka misorientation in-plane a i ʻole out-of-plane. Ua hōʻike mua ʻia nā ʻāpana/papa graphite me nā kihi wili in-plane o 17°, 22° a me 25° no NGF i ulu ʻia ma nā kiʻiʻoniʻoni Ni 64. ʻO nā waiwai kihi wili i ʻike ʻia ma kēia haʻawina ua kūlike me nā kihi wili i ʻike mua ʻia (± 1°) no ka graphene BLG63 i wili ʻia.
Ua ana ʻia nā waiwai uila o NGF/SiO2/Si ma 300 K ma luna o kahi ʻāpana o 10 × 3 mm2. ʻO nā waiwai o ka nui o ka mea lawe uila, ka neʻe ʻana a me ka conductivity he 1.6 × 1020 cm-3, 220 cm2 V-1 C-1 a me 2000 S-cm-1, kēlā me kēia. Ua like nā waiwai mobility a me ka conductivity o kā mākou NGF me ka graphite kūlohelohe2 a ʻoi aku ka kiʻekiʻe ma mua o ka graphite pyrolytic i hoʻonohonoho nui ʻia i loaʻa ma ke kālepa (i hana ʻia ma 3000 °C)29. ʻO nā waiwai nui o ka mea lawe uila i ʻike ʻia he ʻelua kauoha o ka nui ma mua o nā mea i hōʻike hou ʻia (7.25 × 10 cm-3) no nā kiʻiʻoniʻoni graphite micron-mānoanoa i hoʻomākaukau ʻia me ka hoʻohana ʻana i nā pepa polyimide wela kiʻekiʻe (3200 °C) 20.
Ua hana pū mākou i nā ana transmittance UV-ʻike ʻia ma ka FS-NGF i hoʻoili ʻia i nā substrates quartz (Kiʻi 6). Hōʻike ka spectrum hopena i kahi transmittance kokoke mau o 62% ma ka laulā 350-800 nm, e hōʻike ana he translucent ʻo NGF i ka mālamalama ʻike ʻia. ʻOiaʻiʻo, hiki ke ʻike ʻia ka inoa "KAUST" ma ke kiʻi kikohoʻe o ka laʻana ma ke Kiʻi 6b. ʻOiai ʻokoʻa ke ʻano nanocrystalline o NGF mai ko SLG, hiki ke kuhi ʻia ka helu o nā papa me ka hoʻohana ʻana i ke kānāwai o 2.3% pohō hoʻoili no kēlā me kēia papa hou65. Wahi a kēia pilina, ʻo ka helu o nā papa graphene me 38% pohō hoʻoili he 21. ʻO ka NGF i ulu ʻia he 300 mau papa graphene, ʻo ia hoʻi ma kahi o 100 nm ka mānoanoa (Kiʻi 1, SI5 a me SI7). No laila, ke manaʻo nei mākou e pili ana ka transparency optical i ʻike ʻia me nā ʻāpana FLG a me MLG, ʻoiai ua hoʻolaha ʻia lākou ma ke kiʻiʻoniʻoni (Kiʻi 1, 3, 5 a me 6c). Ma waho aʻe o ka ʻikepili hoʻonohonoho ma luna, ua hōʻoia pū ka conductivity a me ka transparency i ke ʻano crystalline kiʻekiʻe o ka NGF i hoʻoili ʻia.
(a) Ke ana ʻana o ka hoʻoili ʻike ʻia e ka UV, (b) ka hoʻoili NGF maʻamau ma ka quartz me ka hoʻohana ʻana i kahi laʻana koho. (c) Kiʻikuhi o NGF (pahu ʻeleʻele) me nā ʻāpana FLG a me MLG i hoʻolaha like ʻia i hōʻailona ʻia he mau ʻano hina hina ma loko o ka laʻana (e ʻike i ke Kiʻi 1) (ma kahi o 0.1–3% o ka ʻāpana no 100 μm2). ʻO nā ʻano maʻamau a me ko lākou nui ma ke kiʻikuhi no nā kumu hoʻohālike wale nō a ʻaʻole pili i nā wahi maoli.
Ua hoʻoili mua ʻia ka NGF translucent i ulu ʻia e CVD i nā ʻili silicon ʻōlohelohe a hoʻohana ʻia i loko o nā cell solar15,16. ʻO ka hopena o ka hoʻololi mana (PCE) he 1.5%. Hana kēia mau NGF i nā hana he nui e like me nā papa hui hana, nā ala lawe ukana, a me nā electrodes transparent15,16. Eia nō naʻe, ʻaʻole like ka ʻili graphite. Pono ka hoʻonui hou ʻana ma ka kaohi pono ʻana i ke kūʻē ʻana o ka pepa a me ka transmittance optical o ka electrode graphite, ʻoiai he kuleana koʻikoʻi kēia mau waiwai ʻelua i ka hoʻoholo ʻana i ka waiwai PCE o ka cell solar15,16. ʻO ka maʻamau, he 97.7% moakāka nā kiʻiʻoniʻoni graphene i ka mālamalama ʻike ʻia, akā he kūʻē pepa o 200-3000 ohms/sq.16. Hiki ke hoʻemi ʻia ke kūʻē ʻana o ka ʻili o nā kiʻiʻoniʻoni graphene ma ka hoʻonui ʻana i ka helu o nā papa (hoʻoili nui o nā papa graphene) a me ka doping me HNO3 (~ 30 Ohm/sq.)66. Eia naʻe, lōʻihi ka manawa o kēia kaʻina hana a ʻaʻole mālama mau nā papa hoʻoili like ʻole i ka pilina maikaʻi. Loaʻa i kā mākou ʻaoʻao mua NGF nā waiwai e like me ka conductivity 2000 S/cm, ke kūpaʻa o ka pepa kiʻiʻoniʻoni 50 ohm/sq. a me ka transparency 62%, e lilo ia i koho kūpono no nā kahawai conductive a i ʻole nā counter electrodes i loko o nā cell solar15,16.
ʻOiai ua like ke ʻano a me ke kemika o ka ʻili o BS-NGF me FS-NGF, ʻokoʻa kona ʻoʻoleʻa ("Ka ulu ʻana o FS- a me BS-NGF"). Ma mua, ua hoʻohana mākou i ka graphite kiʻiʻoniʻoni lahilahi loa22 ma ke ʻano he sensor kinoea. No laila, ua hoʻāʻo mākou i ka hiki ke hoʻohana i ka BS-NGF no nā hana ʻike kinoea (Kiʻi SI10). ʻO ka mea mua, ua hoʻoili ʻia nā ʻāpana mm2 o BS-NGF ma luna o ka chip sensor electrode interdigitating (Kiʻi SI10a-c). Ua hōʻike mua ʻia nā kikoʻī hana o ka chip; ʻo kona wahi koʻikoʻi hana he 9 mm267. Ma nā kiʻi SEM (Kiʻi SI10b a me c), ʻike maopopo ʻia ka electrode gula ma lalo ma o ka NGF. Eia hou, hiki ke ʻike ʻia ua hoʻokō ʻia ka uhi like ʻana o ka chip no nā laʻana āpau. Ua hoʻopaʻa ʻia nā ana sensor kinoea o nā kinoea like ʻole (Kiʻi SI10d) (Kiʻi SI11) a ua hōʻike ʻia nā helu pane hopena ma nā Kiʻi SI10g. ʻOiaʻiʻo paha me nā kinoea ʻē aʻe e hoʻopilikia nei me SO2 (200 ppm), H2 (2%), CH4 (200 ppm), CO2 (2%), H2S (200 ppm) a me NH3 (200 ppm). ʻO kekahi kumu kūpono ʻo NO2. ʻano electrophilic o ke kinoea22,68. Ke hoʻopili ʻia ma luna o ka ʻili o graphene, hoʻemi ia i ka omo ʻana o nā electrons e ka ʻōnaehana. Hōʻike ʻia kahi hoʻohālikelike o ka ʻikepili manawa pane o ka sensor BS-NGF me nā sensor i paʻi mua ʻia ma ka Papa SI2. Ke hoʻomau nei ke ʻano no ka hoʻāla hou ʻana i nā sensor NGF me ka hoʻohana ʻana i ka plasma UV, O3 plasma a i ʻole ka mālama ʻana i ka thermal (50-150°C) o nā laʻana i hōʻike ʻia, ma hope pono o ka hoʻokō ʻana o nā ʻōnaehana i hoʻokomo ʻia69.
I ka wā o ke kaʻina hana CVD, ulu ka graphene ma nā ʻaoʻao ʻelua o ka substrate catalyst41. Eia nō naʻe, hoʻokuʻu pinepine ʻia ka BS-graphene i ka wā o ke kaʻina hana hoʻoili41. Ma kēia haʻawina, hōʻike mākou e hiki ke hoʻokō ʻia ka ulu ʻana o ka NGF kiʻekiʻe a me ka hoʻoili ʻana o ka NGF polymer-free ma nā ʻaoʻao ʻelua o ke kākoʻo catalyst. ʻOi aku ka lahilahi o ka BS-NGF (~80 nm) ma mua o ka FS-NGF (~100 nm), a ua wehewehe ʻia kēia ʻokoʻa e ka ʻoiaʻiʻo ʻaʻole i hōʻike pololei ʻia ʻo BS-Ni i ke kahe kinoea mua. Ua ʻike pū mākou ʻo ka ʻoʻoleʻa o ka substrate NiAR e hoʻopilikia i ka ʻoʻoleʻa o ka NGF. Hōʻike kēia mau hopena hiki ke hoʻohana ʻia ka planar FS-NGF i ulu ʻia ma ke ʻano he mea mua no ka graphene (ma ke ʻano exfoliation70) a i ʻole he kahawai conductive i loko o nā cell solar15,16. I ka hoʻohālikelike ʻana, e hoʻohana ʻia ʻo BS-NGF no ka ʻike ʻana i ke kinoea (Fig. SI9) a malia paha no nā ʻōnaehana mālama ikehu71,72 kahi e pono ai kona ʻoʻoleʻa o ka ʻili.
Ke noʻonoʻo nei i nā mea i luna, he mea pono ke hoʻohui i ka hana o kēia manawa me nā kiʻiʻoniʻoni graphite i paʻi mua ʻia i ulu ʻia e CVD a me ka hoʻohana ʻana i ka pepa nickel. E like me ka mea i ʻike ʻia ma ka Papa 2, ʻo nā kaomi kiʻekiʻe a mākou i hoʻohana ai ua hoʻopōkole i ka manawa hana (kahua ulu) ʻoiai ma nā mahana haʻahaʻa (ma ka pae o 850–1300 °C). Ua hoʻokō pū mākou i ka ulu ʻana ma mua o ka maʻamau, e hōʻike ana i ka hiki ke hoʻonui. Aia kekahi mau mea ʻē aʻe e noʻonoʻo ai, ua hoʻokomo mākou i kekahi o ia mau mea i ka papa.
Ua ulu ʻia ka NGF kiʻekiʻe ʻaoʻao pālua ma luna o ka pepa nickel e ka catalytic CVD. Ma ka hoʻopau ʻana i nā substrates polymer kuʻuna (e like me nā mea i hoʻohana ʻia ma ka graphene CVD), loaʻa iā mākou ka hoʻoili pulu maʻemaʻe a me ka kīnā ʻole o NGF (i ulu ʻia ma nā ʻaoʻao hope a me mua o ka pepa nickel) i nā ʻano substrates koʻikoʻi o ke kaʻina hana. ʻIke ʻia, hoʻokomo pū ʻo NGF i nā ʻāpana FLG a me MLG (maʻamau 0.1% a 3% no 100 µm2) i hoʻohui maikaʻi ʻia i loko o ke kiʻiʻoniʻoni mānoanoa. Hōʻike ʻo Planar TEM ua haku ʻia kēia mau ʻāpana me nā puʻu o ʻelua a ʻekolu mau ʻāpana graphite/graphene (nā kristal a i ʻole nā papa, kēlā me kēia), ʻo kekahi o ia mau mea he mismatch rotational o 10-20°. ʻO nā ʻāpana FLG a me MLG ke kuleana no ka transparency o FS-NGF i ka mālamalama ʻike ʻia. No nā pepa hope, hiki ke lawe ʻia ma ke ʻano like me nā pepa mua a, e like me ka mea i hōʻike ʻia, hiki ke loaʻa kahi kumu hana (no ka laʻana, no ka ʻike ʻana i ke kinoea). He mea pono loa kēia mau haʻawina no ka hōʻemi ʻana i ka ʻōpala a me nā kumukūʻai i nā kaʻina hana CVD pae ʻoihana.
Ma keʻano laulā, aia ka mānoanoa awelika o CVD NGF ma waena o ka graphene (haʻahaʻa a me ka multi-layer) a me nā pepa graphite ʻoihana (micrometer). ʻO ka laulā o ko lākou mau waiwai hoihoi, i hui pū ʻia me ke ʻano maʻalahi a mākou i hoʻomohala ai no kā lākou hana ʻana a me ka lawe ʻana, e hoʻolilo i kēia mau kiʻiʻoniʻoni i kūpono loa no nā noi e koi ana i ka pane hana o ka graphite, me ka ʻole o ke kumukūʻai o nā kaʻina hana ʻoihana ikaika i ka ikehu i hoʻohana ʻia i kēia manawa.
Ua hoʻokomo ʻia kahi pepa nickel 25-μm-mānoanoa (99.5% maʻemaʻe, Goodfellow) i loko o kahi reactor CVD kalepa (Aixtron 4-inch BMPro). Ua hoʻomaʻemaʻe ʻia ka ʻōnaehana me ka argon a ua hoʻoneʻe ʻia i kahi kaomi kumu o 10-3 mbar. A laila ua kau ʻia ka pepa nickel. i loko o Ar/H2 (Ma hope o ka hoʻomoʻa mua ʻana i ka pepa Ni no 5 min, ua hōʻike ʻia ka pepa i kahi kaomi o 500 mbar ma 900 °C. Ua waiho ʻia ʻo NGF i loko o ke kahe o CH4/H2 (100 cm3 kēlā me kēia) no 5 min. A laila ua hoʻomaʻalili ʻia ka laʻana i ka mahana ma lalo o 700 °C me ka hoʻohana ʻana i ke kahe o Ar (4000 cm3) ma 40 °C/min. Ua wehewehe ʻia nā kikoʻī e pili ana i ka hoʻonui ʻana i ke kaʻina hana ulu NGF ma kahi ʻē aʻe30.
Ua ʻike ʻia ke ʻano o ka ʻili o ka hāpana e SEM me ka hoʻohana ʻana i kahi microscope Zeiss Merlin (1 kV, 50 pA). Ua ana ʻia ka ʻoʻoleʻa o ka ʻili o ka hāpana a me ka mānoanoa o NGF me ka hoʻohana ʻana iā AFM (Dimension Icon SPM, Bruker). Ua hoʻokō ʻia nā ana TEM a me SAED me ka hoʻohana ʻana i kahi microscope FEI Titan 80–300 Cubed i lako me kahi pū hoʻokuʻu kahua ʻālohilohi kiʻekiʻe (300 kV), kahi monochromator ʻano FEI Wien a me kahi mea hoʻoponopono aberration spherical lens CEOS e loaʻa ai nā hopena hope loa. hoʻonā spatial 0.09 nm. Ua hoʻoili ʻia nā hāpana NGF i nā grids keleawe i uhi ʻia me ka lacy carbon no ke kiʻi TEM pālahalaha a me ka nānā ʻana i ka hoʻonohonoho SAED. No laila, ua kau ʻia ka hapa nui o nā flocs hāpana i loko o nā pores o ka membrane kākoʻo. Ua kālailai ʻia nā hāpana NGF i hoʻoili ʻia e XRD. Ua loaʻa nā ʻano diffraction X-ray me ka hoʻohana ʻana i ka diffractometer pauka (Brucker, D2 phase shifter me ke kumu Cu Kα, 1.5418 Å a me ka mea ʻike LYNXEYE) me ka hoʻohana ʻana i kahi kumu radiation Cu me ke anawaena kiko kukuna o 3 mm.
Ua hoʻopaʻa ʻia kekahi mau ana o ke kiko Raman me ka hoʻohana ʻana i kahi microscope confocal hoʻohui (Alpha 300 RA, WITeC). Ua hoʻohana ʻia kahi laser 532 nm me ka mana hoʻonāukiuki haʻahaʻa (25%) e pale aku i nā hopena i hoʻoulu ʻia e ka wela. Ua hana ʻia ka spectroscopy photoelectron X-ray (XPS) ma kahi spectrometer Kratos Axis Ultra ma luna o kahi ʻāpana laʻana o 300 × 700 μm2 me ka hoʻohana ʻana i ka radiation monochromatic Al Kα (hν = 1486.6 eV) ma ka mana o 150 W. Ua loaʻa nā spectra hoʻonā ma nā ikehu hoʻoili o 160 eV a me 20 eV, kēlā me kēia. Ua ʻoki ʻia nā laʻana NGF i hoʻoili ʻia ma luna o SiO2 i mau ʻāpana (3 × 10 mm2 kēlā me kēia) me ka hoʻohana ʻana i kahi laser fiber ytterbium PLS6MW (1.06 μm) ma 30 W. Ua hana ʻia nā pilina uea keleawe (50 μm ka mānoanoa) me ka hoʻohana ʻana i ka hoʻopili kālā ma lalo o kahi microscope optical. Ua hoʻokō ʻia nā hoʻokolohua halihali uila a me ka hopena Hall ma luna o kēia mau laʻana ma 300 K a me kahi ʻano like ʻole o ke kahua magnetic o ± 9 Tesla i loko o kahi ʻōnaehana ana waiwai kino (PPMS EverCool-II, Quantum Design, USA). Ua hoʻopaʻa ʻia nā spectra UV-vis i hoʻouna ʻia me ka hoʻohana ʻana i kahi spectrophotometer Lambda 950 UV-vis ma ka pae NGF 350-800 nm i hoʻoili ʻia i nā substrates quartz a me nā laʻana kuhikuhi quartz.
Ua hoʻopili ʻia ke sensor pale kemika (ʻāpana electrode interdigitated) i kahi papa kaapuni paʻi maʻamau 73 a ua unuhi ʻia ke kūʻē no kekahi manawa. Ua hoʻopili ʻia ka papa kaapuni paʻi ma luna o ka mea i kau ʻia ai ka hāmeʻa i nā kikowaena pili a waiho ʻia i loko o ke keʻena ʻike kinoea 74. Ua lawe ʻia nā ana kūʻē ma kahi uila o 1 V me kahi scan hoʻomau mai ka purge a i ka hōʻike ʻana i ke kinoea a laila purge hou. Ua hoʻomaʻemaʻe mua ʻia ke keʻena ma ka hoʻomaʻemaʻe ʻana me ka nitrogen ma 200 cm3 no 1 hola e hōʻoia i ka wehe ʻana o nā analytes ʻē aʻe i loko o ke keʻena, me ka makū. A laila ua hoʻokuʻu mālie ʻia nā analytes pākahi i loko o ke keʻena ma ka helu kahe like o 200 cm3 ma ka pani ʻana i ka cylinder N2.
Ua paʻi ʻia kahi mana i hoʻoponopono hou ʻia o kēia ʻatikala a hiki ke komo ʻia ma o ka loulou ma ka piko o ka ʻatikala.
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