Siyabonga ngokubhalisa ne-Physics World Uma ungathanda ukushintsha imininingwane yakho noma nini, sicela uvakashele i-akhawunti yami
Amafilimu e-graphite angavikela izinto zikagesi emisebeni ye-electromagnetic (EM), kodwa amasu amanje wokuwakhiqiza athatha amahora ambalwa futhi adinga ukucubungula amazinga okushisa angaba ngu-3000 °C. Ithimba labacwaningi abavela e-Shenyang National Laboratory for Materials Science e-Chinese Academy of Sciences manje selibonise enye indlela yokwenza amafilimu e-graphite ekhwalithi ephezulu ngemizuzwana embalwa ngokucisha imicu eshisayo ye-nickel foil ku-ethanol. Izinga lokukhula lalawa mafilimu lingaphezu kwama-oda amabili obukhulu ngaphezu kwezindlela ezikhona, futhi ukusebenza kukagesi namandla amafilimu kuyafana nalawo amafilimu enziwe kusetshenziswa i-chemical vapor deposition (CVD).
Zonke izinto zikagesi zikhiqiza imisebe ethile ye-EM. Njengoba amadivaysi elokhu eba mancane futhi esebenza ngamaza aphezulu nangaphezulu, amandla okuphazanyiswa kwe-electromagnetic (EMI) ayakhula, futhi angaphazamisa kabi ukusebenza kwedivayisi kanye namasistimu kagesi aseduze.
I-graphite, i-allotrope yekhabhoni eyakhiwe ngezingqimba ze-graphene ehlanganiswe ndawonye amandla e-van der Waals, inenani lezinto eziphawulekayo zikagesi, ezishisayo kanye nemishini ezenza ibe isivikelo esisebenzayo ngokumelene ne-EMI. Kodwa-ke, idinga ukuba sesimweni sefilimu ezacile kakhulu ukuze ibe nokuhamba kukagesi okuphezulu, okubalulekile ezinhlelweni ezisebenzayo ze-EMI ngoba kusho ukuthi impahla ingabonisa futhi imunce amagagasi e-EM njengoba exhumana nabathwali bokushaja ngaphakathi. yona.
Njengamanje, izindlela eziyinhloko zokwenza ifilimu ye-graphite zifaka i-pyrolysis yezinga lokushisa eliphezulu lama-polymer anephunga elimnandi noma ukunqwabelanisa i-graphene (GO) oxide noma i-graphene nanosheets layer by layer. Zombili lezi zinqubo zidinga amazinga okushisa acishe abe 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 anogqinsi lwe-nanometre, ngisho nalapho kungenalutho.
Ithimba eliholwa u-Wencai Ren manje selikhiqize ifilimu ye-graphite yekhwalithi ephezulu amashumi ama-nanometers awugqinsi phakathi kwemizuzwana embalwa ngokushisisa i-nickel foil ibe ngu-1200 °C endaweni ye-argon bese icwilisa le foil ngokushesha ku-ethanol ku-0 °C. Ama-athomu ekhabhoni akhiqizwa ngokubola kwe-ethanol asakazeka futhi ancibilike ku-nickel ngenxa yokuncibilika kwekhabhoni okuphezulu kwensimbi (0.4 wt% ku-1200 °C). Ngenxa yokuthi lokhu kuncibilika kwekhabhoni kuncipha kakhulu ezingeni lokushisa eliphansi, ama-athomu ekhabhoni abe esehlukanisa futhi ehle endaweni ye-nickel ngesikhathi sokucisha, akhiqize ifilimu eliwugqinsi legraphite. Abacwaningi babika ukuthi umsebenzi omuhle kakhulu we-nickel we-catalytic usiza futhi ukwakheka kwe-crystalline graphite.
Besebenzisa inhlanganisela ye-high-resolution transmission microscopy, i-X-ray diffraction kanye ne-Raman spectroscopy, u-Ren nozakwabo bathola ukuthi i-graphite abayikhiqizile yayicwebezele kakhulu ezindaweni ezinkulu, igqize kahle futhi ingenawo amaphutha abonakalayo. I-electron conductivity yefilimu yayiphezulu ngokungu-2.6 x 105 S/m, efana namafilimu akhuliswe i-CVD noma amasu okushisa aphezulu kanye nokucindezelwa kwamafilimu e-GO/graphene.
Ukuhlola ukuthi impahla ingavimba kanjani imisebe ye-EM, ithimba lidlulise amafilimu anendawo engu-600 mm2 kuma-substrates enziwe nge-polyethylene terephthalate (PET). Babe sebelinganisa ukusebenza kokuvikela kwe-EMI kwefilimu (SE) ebangeni lefrikhwensi ye-X-band, phakathi kuka-8.2 no-12.4 GHz. Bathole i-EMI SE engaphezu kuka-14.92 dB yefilimu ecishe ibe ngu-77 nm obukhulu. Leli nani liyakhuphuka libe ngaphezu kuka-20 dB (inani elincane elidingekayo lezinhlelo zokusebenza zezentengiso) kulo lonke ibhendi engu-X lapho benqwabelanisa amafilimu engeziwe. Ngempela, ifilimu equkethe izingcezu ezinhlanu zamafilimu e-graphite astakiwe (acishe abe ngu-385 nm ubukhulu esewonke) ine-EMI SE ecishe ibe ngu-28 dB, okusho ukuthi okokusebenza kungavimba u-99.84% wemisebe yesigameko. Sekukonke, ithimba lilinganise ukuvikela kwe-EMI okungu-481,000 dB/cm2/g kulo lonke i-X-band, okwenza kahle kakhulu ngaphezu kwazo zonke izinto zokwenziwa ezibikwe ngaphambilini.
Abacwaningi bathi ngokwazi kwabo konke, ifilimu yabo ye-graphite iyona mncane phakathi kwezinto ezivikelayo ezibikiwe, ngokusebenza kokuvikela kwe-EMI okunganelisa imfuneko yezicelo zentengiso. Izakhiwo zayo zemishini nazo ziyathandeka. Amandla okuphuka kwempahla acishe abe ngu-110 MPa (ekhishwe ku-stress-strain curves wento ebekwe phezu kosekelo lwe-polycarbonate) aphakeme kunalawo amafilimu e-graphite atshalwe ngezinye izindlela. Ifilimu iyavumelana nezimo, futhi, futhi ingagotshwa izikhathi eziyi-1000 nge-radius egobayo engu-5 mm ngaphandle kokulahlekelwa izakhiwo zayo zokuvikela i-EMI. Iphinde iqine ngokushisa ifinyelele ku-550 °C. Ithimba likholelwa ukuthi lezi nezinye izakhiwo zisho ukuthi zingasetshenziswa njengezinto ezivikelayo ze-EMI eziguquguqukayo nezisebenzayo ezisetshenziswa ezindaweni eziningi, okuhlanganisa i-aerospace kanye ne-electronics kanye ne-optoelectronics.
Funda intuthuko ebaluleke kakhulu nejabulisayo kusayensi yezinto zokwakha kuleli jenali entsha yokufinyelela evulekile.
I-Physics World imele ingxenye ebalulekile yenjongo ye-IOP Publishing yokuxhumana ngocwaningo olusezingeni lomhlaba kanye nokuqamba izinto ezintsha kubabukeli abaningi ngangokunokwenzeka. Isizindalwazi siyingxenye yephothifoliyo ye-Physics World, iqoqo lezinsiza zolwazi eziku-inthanethi, zedijithali kanye nezokuphrinta zomphakathi womhlaba wezesayensi.
Isikhathi sokuthumela: May-07-2020