Siyabonga ngokubhalisa ne-Physics World Uma ungathanda ukushintsha imininingwane yakho nganoma yisiphi isikhathi, sicela uvakashele i-akhawunti yami
Amafilimu e-graphite angavikela amadivayisi kagesi emisebeni ye-electromagnetic (EM), kodwa amasu amanje okuwakhiqiza athatha amahora amaningana futhi adinga amazinga okushisa okucubungula angaba ngu-3000 °C. Ithimba labacwaningi abavela eShenyang National Laboratory for Materials Science e-Chinese Academy of Sciences manje selibonise enye indlela yokwenza amafilimu e-graphite asezingeni eliphezulu ngemizuzwana embalwa nje ngokucima imichilo eshisayo ye-nickel foil ku-ethanol. Izinga lokukhula lala mafilimu liphakeme kakhulu kunezindlela ezikhona, futhi ukuhanjiswa kukagesi kwamafilimu kanye namandla omshini kuhambisana nalawo amafilimu enziwe kusetshenziswa i-chemical vapour deposition (CVD).
Zonke izinto ezisetshenziswa ngogesi zikhiqiza imisebe ethile ye-EM. Njengoba izinto ezisetshenziswa ngogesi ziba zincane futhi zisebenza ngamaza aphezulu naphezulu, amathuba okuphazamiseka kwe-electromagnetic (EMI) ayanda, futhi angathinta kabi ukusebenza kwento kanye nokwezinhlelo zikagesi eziseduze.
I-Graphite, i-allotrope yekhabhoni eyakhiwe ngezingqimba ze-graphene ezihlanganiswe ndawonye ngamandla e-van der Waals, inezakhiwo eziningi zikagesi, ezishisayo nezemishini eziyenza ibe yisivikelo esisebenzayo ngokumelene ne-EMI. Kodwa-ke, idinga ukuba sesimweni sefilimu encane kakhulu ukuze ibe nokuqhuba kukagesi okuphezulu, okubalulekile ekusetshenzisweni kwe-EMI okusebenzayo ngoba kusho ukuthi izinto zingabonakalisa futhi zimunce amagagasi e-EM njengoba esebenzisana nabathwali beshaja ngaphakathi kwayo.
Njengamanje, izindlela eziyinhloko zokwenza ifilimu ye-graphite zihilela i-pyrolysis yokushisa okuphezulu kwama-polymer aromatic noma ukufaka i-graphene oxide (GO) oxide noma i-graphene nanosheets ungqimba ngengqimba. Zombili lezi zinqubo zidinga amazinga okushisa aphezulu angaba ngu-3000 °C kanye nezikhathi zokucubungula zehora. Ku-CVD, amazinga okushisa adingekayo aphansi (phakathi kuka-700 kuya ku-1300 °C), kodwa kuthatha amahora ambalwa ukwenza amafilimu anobukhulu be-nanometer, ngisho nase-vacuum.
Ithimba eliholwa nguWencai Ren manje selikhiqize ifilimu ye-graphite esezingeni eliphezulu eyishumi lama-nanometers ubukhulu ngemizuzwana embalwa ngokufudumeza i-nickel foil ku-1200 °C emoyeni we-argon bese lifaka ngokushesha le foil ku-ethanol ku-0 °C. Ama-athomu e-carbon akhiqizwa ngokubola kwe-ethanol ayasakazeka futhi ancibilike abe yi-nickel ngenxa yokuncibilika okukhulu kwe-carbon kwensimbi (0.4 wt% ku-1200 °C). Ngenxa yokuthi lokhu kuncibilika kwe-carbon kunciphisa kakhulu ekushiseni okuphansi, ama-athomu e-carbon kamuva ayahlukanisa futhi awe phansi ebusweni be-nickel ngesikhathi sokucinywa, akhiqize ifilimu ye-graphite ejiyile. Abacwaningi babika ukuthi umsebenzi omuhle kakhulu we-catalytic we-nickel usiza futhi ekwakhekeni kwe-graphite ekristalu kakhulu.
Besebenzisa inhlanganisela ye-high-resolution transmission microscopy, i-X-ray diffraction kanye ne-Raman spectroscopy, uRen kanye nozakwabo bathole ukuthi i-graphite abayikhiqizile yayicwebezela kakhulu ezindaweni ezinkulu, inezingqimba ezinhle futhi ayinazo iziphambeko ezibonakalayo. Ukuhanjiswa kwe-electron kwefilimu kwakuphakeme njengo-2.6 x 105 S/m, okufana namafilimu akhuliswe yi-CVD noma amasu okushisa aphezulu kanye nokucindezela amafilimu e-GO/graphene.
Ukuze kuhlolwe ukuthi izinto zingavimba kahle kangakanani imisebe ye-EM, ithimba lidlulisele amafilimu anendawo engaphezulu engu-600 mm2 kuma-substrate enziwe nge-polyethylene terephthalate (PET). Base belinganisa ukusebenza kahle kwe-EMI shielding (SE) yefilimu ebangeni lemvamisa ye-X-band, phakathi kuka-8.2 no-12.4 GHz. Bathole i-EMI SE engaphezu kuka-14.92 dB yefilimu engaba ngu-77 nm ubukhulu. Leli nani likhuphuka libe ngaphezu kuka-20 dB (inani elincane elidingekayo ezinhlelweni zezentengiselwano) kuyo yonke i-X-band lapho behlanganisa amafilimu engeziwe ndawonye. Ngempela, ifilimu equkethe izingcezu ezinhlanu zamafilimu e-graphite ahlanganisiwe (cishe ubukhulu obungu-385 nm) ine-EMI SE engaba ngu-28 dB, okusho ukuthi izinto zingavimba u-99.84% wemisebe yesigameko. Sekukonke, ithimba lilinganise ukuvikela kwe-EMI okungu-481,000 dB/cm2/g kulo lonke i-X-band, okwenza kube ngcono kakhulu kuzo zonke izinto zokwenziwa ezibikiwe ngaphambilini.
Abacwaningi bathi ngokwazi kwabo konke, ifilimu yabo ye-graphite iyona encane kunazo zonke phakathi kwezinto zokuvikela ezibikiwe, enokusebenza kokuvikela kwe-EMI okungahlangabezana nezidingo zezicelo zezentengiselwano. Izakhiwo zayo zomshini nazo zinhle. Amandla okuphuka kwezinto angaba ngu-110 MPa (athathwe kuma-curve okucindezeleka-ukucindezeleka kwezinto ezibekwe ekusekelweni kwe-polycarbonate) aphezulu kunalawo amafilimu e-graphite akhuliswe ngezinye izindlela. Ifilimu nayo iyaguquguquka, futhi ingagotshwa izikhathi eziyi-1000 nge-radius egobile engu-5 mm ngaphandle kokulahlekelwa yizakhiwo zayo zokuvikela ze-EMI. Iphinde izinzile ngokushisa kuze kufike ku-550 °C. Ithimba likholelwa ukuthi lezi nezinye izakhiwo zisho ukuthi zingasetshenziswa njengento yokuvikela ye-EMI encane kakhulu, elula, eguquguqukayo futhi ephumelelayo yokusetshenziswa ezindaweni eziningi, kufaka phakathi izindiza kanye ne-electronics kanye ne-optoelectronics.
Funda intuthuko ebaluleke kakhulu nejabulisayo kwisayensi yezinto ezibonakalayo kule ncwadi entsha yokufinyelela evulekile.
I-Physics World imele ingxenye ebalulekile yomsebenzi we-IOP Publishing wokuxhumana ngocwaningo kanye nokusungula izinto ezintsha okusezingeni lomhlaba kubabukeli abaningi ngangokunokwenzeka. Le webhusayithi iyingxenye yephothifoliyo ye-Physics World, iqoqo lezinsizakalo zolwazi eziku-inthanethi, zedijithali kanye neziphrintiwe zomphakathi wesayensi womhlaba wonke.
Isikhathi sokuthunyelwe: Meyi-07-2020