Filimi ya grafiti ikura vuba ibuza imirasire ya elegitoroniki

Urakoze kwiyandikisha muri Physics World Niba wifuza guhindura amakuru yawe igihe icyo ari cyo cyose, sura konti yanjye

Filimi za grafiti zishobora kurinda ibikoresho by'ikoranabuhanga imirasire ya electromagnetic (EM), ariko ubuhanga bugezweho bwo kubikora butwara amasaha menshi kandi busaba ubushyuhe bwa dogere selisiyusi 3000. Itsinda ry'abashakashatsi bo muri Laboratwari y'Igihugu ya Shenyang ishinzwe Ubumenyi bw'Ibikoresho mu Ishuri Rikuru ry'Ubumenyi ry'Abashinwa ubu ryagaragaje ubundi buryo bwo gukora filime za grafiti nziza mu masegonda make gusa bazimya uduce dushyushye twa nickel foil muri ethanol. Igipimo cy'iterambere ry'izi filime kiri hejuru cyane ugereranyije n'uburyo busanzweho, kandi imbaraga z'amashanyarazi n'ingufu za mashini za filime zihwanye n'iza filime zakozwe hakoreshejwe umwuka wa chimique (CVD).

Ibikoresho byose by'ikoranabuhanga bitanga imirasire ya EM. Uko ibikoresho bigenda birushaho kuba bito kandi bigakora ku murongo wo hejuru cyane, ubushobozi bwo kubangamira amashanyarazi (EMI) buriyongera, kandi bushobora kugira ingaruka mbi ku mikorere y'igikoresho ndetse n'iya sisitemu z'ikoranabuhanga ziri hafi aho.

Graphite, ubwoko bwa karuboni bwubatswe mu byiciro bya graphene bifatanye n'imbaraga za van der Waals, ifite imiterere myinshi itangaje y'amashanyarazi, ubushyuhe n'imikorere ya mekanike ituma iba ingabo irinda EMI. Ariko, igomba kuba ifite ishusho y'icyuma gito cyane kugira ngo igire amashanyarazi menshi, ibi bikaba ari ingenzi mu bikorwa bya EMI kuko bivuze ko ibikoresho bishobora kugaragaza no kwinjiza imiraba ya EM mu gihe bikorana n'ibikoresho biyitwaramo umuriro.

Muri iki gihe, uburyo bw'ingenzi bwo gukora filime ya grafiti burimo pyrolysis y'ubushyuhe bwinshi ya polymers cyangwa gushyira hamwe graphene (GO) oxide cyangwa graphene nanosheets urwego ku rundi. Inzira zombi zisaba ubushyuhe bwinshi bwa dogere selisiyusi 3000 n'igihe cyo gutunganya isaha. Muri CVD, ubushyuhe bukenewe buri hasi (hagati ya dogere selisiyusi 700 na 1300), ariko bifata amasaha make gukora filime zifite ubunini bwa nanometero, ndetse no mu cyuma gifunze.

Itsinda riyobowe na Wencai Ren ubu ryakoze filime ya grafiti nziza cyane y’ubugari bwa nanometero mirongo mu masegonda make binyuze mu gushyushya filime ya nickel kugeza kuri 1200 °C mu kirere cya argon hanyuma bigahita byinjiza iyi filime muri ethanol kuri 0 °C. Atome za karuboni zikorwa mu kubora kwa ethanol zikwirakwira mu filime ya nickel bitewe n’uko icyuma gishonga cyane (0.4 wt% kuri 1200 °C). Kubera ko uku gushonga kwa karuboni kugabanuka cyane iyo ubushyuhe buke, atome za karuboni zihita zitandukana zikava ku buso bwa nickel mu gihe cyo kuzimya, bigatuma filime ya grafiti ikomeye. Abashakashatsi bavuga ko imikorere myiza ya nickel ifasha kandi mu ikorwa rya graphite ifite kristale nyinshi.

Bakoresheje uburyo bwo gupima no gupima amashusho hakoreshejwe ikoranabuhanga rya "high-resolution transmission mikroscopi", "X-ray diffraction" na "Raman spectroscopy", Ren na bagenzi be basanze grafiti bakoze yari ifite kristali nyinshi ku bice binini, ifite urwego rwiza kandi nta nenge zigaragara zari zirimo. Uburyo electron conductivity ya filime yari ifite uburebure bwa 2.6 x 105 S/m, kimwe na filime zakozwe hakoreshejwe CVD cyangwa tekiniki zikoresha ubushyuhe bwinshi hamwe no gukanda filime za GO/graphene.

Kugira ngo bagerageze uburyo ibikoresho bishobora kuziba imirasire ya EM, itsinda ryimuriye filime zifite ubuso bwa mm2 600 ku byuma bikozwe muri polyethylene terephthalate (PET). Hanyuma bapimye ubushobozi bwa filime bwo kuziba EMI (SE) mu gipimo cya X-band, hagati ya 8.2 na 12.4 GHz. Basanze EMI SE irenga 14.92 dB kuri filime ifite ubugari bwa nm 77. Iki giciro kiriyongera kigera kuri dB zirenga 20 (agaciro ntarengwa gasabwa mu bikorwa by'ubucuruzi) muri X-band yose igihe bateranyaga filime nyinshi. Mu by'ukuri, filime irimo ibice bitanu bya filime za grafiti (zigera kuri 385 nm z'ubugari bwose) ifite EMI SE igera kuri 28 dB, bivuze ko ibikoresho bishobora kuziba 99.84% by'imirasire y'impanuka. Muri rusange, itsinda ryapimye EMI shielding ya 481.000 dB/cm2/g kuri X-band, irusha ibikoresho byose byakozwe mbere.

Abashakashatsi bavuga ko uko babizi, filime yabo ya grafiti ni yo nto cyane mu zivugwa mu bikoresho byo kurinda, ifite imikorere ya EMI ishobora guhaza ibisabwa mu bucuruzi. Imiterere yayo ya mekanike nayo ni myiza. Ingufu zo gucika kw'ibikoresho zingana na 110 MPa (ikurwa mu mitsi y'imbaraga z'ibikoresho bishyirwa ku gikoresho cya polycarbonate) ziri hejuru y'iza filime za grafiti zakuwemo n'ubundi buryo. Iyi filime nayo irahinduka, kandi ishobora kunamikwa inshuro 1000 hamwe n'umurambararo wa mm 5 udatakaje imiterere yayo ya EMI yo kurinda. Ifite kandi ubushyuhe buhamye kugeza kuri 550 °C. Itsinda ryizera ko iyi miterere n'indi imiterere bivuze ko ishobora gukoreshwa nk'ibikoresho byo kurinda EMI bito cyane, byoroshye, byoroshye kandi bikora neza mu bikorwa mu bice byinshi, harimo iby'ikirere ndetse n'ibikoresho by'ikoranabuhanga na optoelectronics.

Soma iterambere rikomeye kandi rishimishije mu bumenyi bw'ibikoresho muri iki kinyamakuru gishya cy’ubumenyi bw’ibikoresho.

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