Na gode don yin rijista tare da Duniyar Kimiyyar Kimiyya Idan kuna son canza bayananku a kowane lokaci, da fatan za a ziyarci asusuna
Fina-finan graphite na iya kare na'urorin lantarki daga hasken lantarki na lantarki (EM), amma dabarun kera su suna ɗaukar sa'o'i da yawa kuma suna buƙatar sarrafa yanayin zafi na kusan 3000 ° C. Tawagar masu bincike daga dakin gwaje-gwaje na kimiyyar kere-kere na Shenyang na Kwalejin Kimiyya ta kasar Sin, yanzu sun nuna wata hanya ta daban ta yin fina-finai masu inganci a cikin 'yan dakiku kadan ta hanyar kashe zafafan filaye na nickel a cikin sinadarin ethanol. Girman girma ga waɗannan fina-finai ya fi umarni biyu mafi girma fiye da hanyoyin da ake da su, kuma ƙarfin lantarki na fina-finai da ƙarfin injin sun yi daidai da na fina-finai da aka yi ta amfani da sinadarai na tururi (CVD).
Duk na'urorin lantarki suna samar da wasu EM radiation. Yayin da na'urori ke ƙara ƙanƙanta kuma suna aiki a mafi girma kuma mafi girma mitoci, yuwuwar tsoma bakin na'urar lantarki (EMI) na girma, kuma yana iya yin illa ga aikin na'urar da na na'urorin lantarki da ke kusa.
Graphite, wani allotrope na carbon da aka gina daga yadudduka na graphene tare da sojojin van der Waals, yana da adadi na ban mamaki na lantarki, thermal da injuna waɗanda ke sa ya zama garkuwa mai inganci ga EMI. Duk da haka, yana buƙatar kasancewa a cikin nau'i na fim mai mahimmanci don samun babban ƙarfin lantarki, wanda ke da mahimmanci ga aikace-aikacen EMI mai amfani saboda yana nufin cewa abu zai iya yin tunani da kuma ɗaukar raƙuman EM yayin da suke hulɗa tare da masu ɗaukar kaya a ciki. shi.
A halin yanzu, manyan hanyoyin yin graphite film unsa ko dai high-zazzabi pyrolysis na aromatic polymers ko stacking up graphene (GO) oxide ko graphene nanosheets Layer ta Layer. Duka matakai biyu suna buƙatar babban yanayin zafi na kusan 3000 °C da lokutan sarrafawa na sa'a guda. A cikin CVD, yanayin zafi da ake buƙata yana ƙasa (tsakanin 700 zuwa 1300 ° C), amma yana ɗaukar sa'o'i kaɗan don yin fina-finai masu kauri na nanometer, har ma a cikin injin.
Tawagar da Wencai Ren ke jagoranta a yanzu ta samar da ingantaccen fim ɗin graphite dubun nanometer mai kauri a cikin 'yan daƙiƙa kaɗan ta hanyar dumama foil nickel zuwa 1200 ° C a cikin yanayin argon sannan kuma cikin sauri nutsar da wannan foil a cikin ethanol a 0 ° C. Atom ɗin carbon da aka samar daga rushewar ethanol kuma suna narkar da su cikin nickel godiya ga ƙarfin ƙarfe mai ƙarfi na carbon (0.4 wt% a 1200 ° C). Saboda wannan sinadarin carbon solubility yana raguwa sosai a ƙananan zafin jiki, daga baya carbon atom ya keɓance da hazo daga saman nickel yayin quenching, yana samar da fim mai kauri. Masu binciken sun ba da rahoton cewa kyakkyawan aikin nickel kuma yana taimakawa samuwar graphite mai kristal sosai.
Yin amfani da haɗe-haɗe na ƙananan ƙwararrun watsa shirye-shirye, X-ray diffraction da Raman spectroscopy, Ren da abokan aiki sun gano cewa graphite da suka samar ya kasance mai lu'ulu'u sosai a kan manyan wurare, yana da kyau kuma ba shi da wani lahani na gani. Halin wutar lantarki na fim ɗin ya kai 2.6 x 105 S / m, kama da fina-finai da aka girma ta hanyar CVD ko fasahar zafin jiki da kuma danna fina-finai na GO/graphene.
Don gwada yadda kayan zai iya toshe radiation na EM, ƙungiyar ta tura fina-finai masu girman 600 mm2 zuwa abubuwan da aka yi da polyethylene terephthalate (PET). Sannan sun auna tasirin garkuwar EMI na fim ɗin (SE) a cikin kewayon mitar X-band, tsakanin 8.2 da 12.4 GHz. Sun sami EMI SE na fiye da 14.92 dB don fim ɗin kusan 77 nm lokacin farin ciki. Wannan ƙimar yana ƙaruwa zuwa fiye da 20 dB (mafi ƙarancin ƙimar da ake buƙata don aikace-aikacen kasuwanci) a cikin duka-band X lokacin da suka tattara ƙarin fina-finai tare. Lallai, fim ɗin da ke ɗauke da guda biyar na fina-finan graphite (kimanin kauri na 385 nm gabaɗaya) yana da EMI SE na kusan 28 dB, wanda ke nufin cewa kayan na iya toshe kashi 99.84% na hasken da ya faru. Gabaɗaya, ƙungiyar ta auna garkuwar EMI na 481,000 dB/cm2/g a fadin rukunin X, wanda ya zarce duk kayan da aka ruwaito a baya.
Masu binciken sun ce a iyakar saninsu, fim ɗin graphite ɗin su shine mafi ƙanƙanta a cikin kayan kariya da aka ruwaito, tare da aikin garkuwar EMI wanda zai iya biyan buƙatun aikace-aikacen kasuwanci. Its kayan aikin injiniya kuma suna da kyau. Ƙarfin karyewar kayan na kusan 110 MPa (wanda aka cire daga damuwa-matsalolin kayan da aka sanya akan tallafin polycarbonate) ya fi na fina-finan graphite girma ta wasu hanyoyin. Fim ɗin yana da sassauƙa, kuma, kuma ana iya lanƙwasa sau 1000 tare da radius na lanƙwasa na 5 mm ba tare da rasa kayan kariya na EMI ba. Hakanan yana da kwanciyar hankali har zuwa 550 ° C. Ƙungiyar ta yi imanin cewa waɗannan da sauran kaddarorin suna nufin cewa za a iya amfani da shi azaman ultrathin, nauyi, sassauƙa da ingantaccen kayan kariya na EMI don aikace-aikace a wurare da yawa, ciki har da sararin samaniya da kuma kayan lantarki da optoelectronics.
Karanta mafi mahimmanci kuma mai ban sha'awa ci gaba a kimiyyar kayan aiki a cikin wannan sabuwar jarida mai samun damar shiga.
Duniyar Physics tana wakiltar babban ɓangaren manufar IOP Publishing don sadar da bincike-bincike na duniya ga mafi yawan masu sauraro. Gidan yanar gizon ya samar da wani ɓangare na Fayil ɗin Duniya na Physics, tarin kan layi, dijital da sabis na bayanan bugu don al'ummar kimiyyar duniya.
Lokacin aikawa: Mayu-07-2020