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Iifilimu zegrafiti zingakhusela izixhobo ze-elektroniki kwimitha ye-electromagnetic (EM), kodwa iindlela zangoku zokuzivelisa zithatha iiyure ezininzi kwaye zifuna ukucubungula amaqondo obushushu amalunga ne-3000 °C. Iqela labaphandi abavela kwiShenyang National Laboratory for Materials Science kwiChinese Academy of Sciences ngoku libonise enye indlela yokwenza iifilimu zegrafiti ezikumgangatho ophezulu kwimizuzwana embalwa ngokucima imicu eshushu ye-nickel foil kwi-ethanol. Izinga lokukhula kwezi filimu lingaphezulu kwe-odolo ezimbini ngobukhulu kuneendlela ezikhoyo, kwaye ukuhanjiswa kombane kweefilimu kunye namandla oomatshini ahambelana nalawo eefilimu ezenziwe kusetyenziswa i-chemical vapour deposition (CVD).
Zonke izixhobo ze-elektroniki zivelisa imitha ethile ye-EM. Njengoko izixhobo zisiba zincinci kwaye zisebenza kumaza aphezulu naphezulu, amathuba okuphazamiseka kwe-electromagnetic (EMI) ayanda, kwaye anokuchaphazela kakubi ukusebenza kwesixhobo kunye nokweenkqubo ze-elektroniki ezikufutshane.
I-Graphite, i-allotrope yekhabhoni eyakhiwe ngamaleya e-graphene ebanjwe kunye yimikhosi ye-van der Waals, ineempawu ezininzi eziphawulekayo zombane, ubushushu kunye noomatshini ezenza ukuba ibe sisikhuselo esisebenzayo kwi-EMI. Nangona kunjalo, kufuneka ibe kwimo yefilimu encinci kakhulu ukuze ibe nombane ophezulu oqhubayo, nto leyo ibalulekileyo kwizicelo ze-EMI ezisebenzayo kuba kuthetha ukuba izinto zinokubonakalisa kwaye zifunxe amaza e-EM njengoko edibana nabathwali betshaja ngaphakathi kuyo.
Okwangoku, iindlela eziphambili zokwenza ifilimu yegrafiti ziquka i-pyrolysis yobushushu obuphezulu beepolymers ezinuka kamnandi okanye ukufaka i-graphene oxide (GO) okanye i-graphene nanosheets umaleko ngomaleko. Zombini ezi nkqubo zifuna amaqondo obushushu aphezulu amalunga ne-3000 °C kunye namaxesha okucubungula eyure. Kwi-CVD, amaqondo obushushu afunekayo aphantsi (phakathi kwe-700 ukuya kwi-1300 °C), kodwa kuthatha iiyure ezimbalwa ukwenza iifilimu ezinobukhulu be-nanometer, nokuba kukwi-vacuum.
Iqela elikhokelwa nguWencai Ren ngoku livelise ifilimu yegrafiti ekumgangatho ophezulu amashumi eenanomitha ubukhulu kwimizuzwana embalwa ngokufudumeza i-nickel foil ukuya kwi-1200 °C kwi-argon atmosphere kwaye emva koko ifaka le foil ngokukhawuleza kwi-ethanol kwi-0 °C. Iiathom zekhabhoni eziveliswa kukubola kwe-ethanol ziyasasazeka kwaye zinyibilike kwi-nickel ngenxa yokunyibilika kwekhabhoni ephezulu yesinyithi (0.4 wt% kwi-1200 °C). Ngenxa yokuba oku kunyibilika kwekhabhoni kuncipha kakhulu kubushushu obuphantsi, iiathom zekhabhoni emva koko ziyahlukana kwaye ziphume kumphezulu we-nickel ngexesha lokucinywa, zivelise ifilimu yegrafiti etyebileyo. Abaphandi baxela ukuba umsebenzi ogqwesileyo we-catalytic we-nickel ukwanceda ekwakhiweni kwegrafiti ekristale kakhulu.
Besebenzisa indibaniselwano ye-high-resolution transmission microscopy, i-X-ray diffraction kunye ne-Raman spectroscopy, uRen kunye noogxa bakhe bafumanise ukuba i-graphite abayivelisileyo yayinekristale ephezulu kwiindawo ezinkulu, ineeleya ezintle kwaye ayinazo iziphene ezibonakalayo. Ukuhanjiswa kwee-electron kwefilimu kwakuphezulu njenge-2.6 x 105 S/m, kufana neefilimu ezikhuliswe yi-CVD okanye iindlela zobushushu obuphezulu kunye nokucinezelwa kweefilimu ze-GO/graphene.
Ukuze kuvavanywe ukuba le nto ingawuthintela njani na umthambeka we-EM, iqela lidlulisele iifilimu ezinomphezulu we-600 mm2 kwii-substrates ezenziwe nge-polyethylene terephthalate (PET). Emva koko balinganise ukusebenza kwe-EMI shielding (SE) yefilimu kuluhlu lwee-frequency ze-X-band, phakathi kwe-8.2 kunye ne-12.4 GHz. Bafumene i-EMI SE engaphezulu kwe-14.92 dB kwifilimu emalunga ne-77 nm ubukhulu. Eli xabiso linyuka liye ngaphezulu kwe-20 dB (ixabiso elincinci elifunekayo kwizicelo zorhwebo) kuyo yonke i-X-band xa behlanganisa iifilimu ezininzi. Enyanisweni, ifilimu equlethe iziqwenga ezihlanu zeefilimu ze-graphite ezihlanganisiweyo (malunga ne-385 nm ubukhulu iyonke) ine-EMI SE emalunga ne-28 dB, oko kuthetha ukuba le nto inokuthintela i-99.84% yemitha yesiganeko. Lilonke, iqela lilinganise ukhuseleko lwe-EMI lwe-481,000 dB/cm2/g kulo lonke i-X-band, luphumelela ngaphezu kwazo zonke izinto ezenziweyo ezichazwe ngaphambili.
Abaphandi bathi ngokolwazi lwabo, ifilimu yabo yegrafiti yeyona incinci kakhulu phakathi kwezinto ezikhankanyiweyo zokukhusela, kunye nokusebenza kwe-EMI shielding okunokwanelisa imfuneko yezicelo zorhwebo. Iimpawu zayo zoomatshini nazo zilungile. Amandla okuqhekeka kwezixhobo ze-110 MPa (ezithathwe kwii-stress-strain curves zezinto ezibekwe kwinkxaso ye-polycarbonate) aphezulu kunalawo eefilimu zegrafiti ezikhuliswe zezinye iindlela. Ifilimu nayo iguquguquka, kwaye ingagotywa amaxesha ali-1000 nge-radius egobileyo ye-5 mm ngaphandle kokulahlekelwa ziimpawu zayo zokukhusela ze-EMI. Ikwazinzile kubushushu ukuya kuthi ga kwi-550 °C. Iqela likholelwa ukuba ezi kunye nezinye iimpawu zithetha ukuba ingasetyenziswa njengesixhobo sokukhusela se-EMI esincinci kakhulu, esikhaphukhaphu, esiguquguqukayo nesisebenzayo kwiindawo ezininzi, kubandakanya i-aerospace kunye ne-electronics kunye ne-optoelectronics.
Funda inkqubela phambili ebalulekileyo neyonwabisayo kwisayensi yezinto ezisetyenziswayo kule ncwadana intsha yokufikelela evulekileyo.
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Ixesha lokuthumela: Meyi-07-2020