{"id":22948,"date":"2011-11-30T20:11:13","date_gmt":"2011-11-30T17:11:13","guid":{"rendered":"http:\/\/www.fyysika.ee\/uudised\/?p=22948"},"modified":"2011-12-15T10:33:53","modified_gmt":"2011-12-15T07:33:53","slug":"defektid-voivad-grafeensensoreid-paremaks-muuta","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=22948","title":{"rendered":"Defektid v\u00f5ivad grafeensensoreid paremaks muuta"},"content":{"rendered":"

Kuigi Illinoisi \u00dclikooli teadlased leidsid, et grafeenist saab valmistada \u00fclih\u00e4id keemilisi sensoreid, panid nad t\u00e4hele ka \u00fcllatavat t\u00f5siasja: sensorid on veelgi paremad, kui grafeen ise on ”halvem” – rohkem defekte t\u00e4hendab paremaid t\u00f6\u00f6omadusi.<\/strong><\/p>\n

,,See on t\u00e4iesti vastupidine sellele, mida me vajame transistorite jaoks,” s\u00f5nas Eric Pop<\/strong>, uurimisgrupi \u00fcks liikmetest. ,,Fakt, et mida halvem grafeen oli, seda paremini see t\u00f6\u00f6tas, tundus alguses t\u00e4iesti ebaloomulik,” kirjutab Physorg.com<\/a>.<\/p>\n

\"\"<\/a>

Pilt: Advanced Materials<\/p><\/div>\n

,,Selle uurimuse eesm\u00e4rgiks oli teha kindlaks, mis piirab lihtsate kaheklemmiliste grafeenip\u00f5histe keemiliste sensorite tundlikkust ning uurida seda odavate keemilise sadestusmeetodiga (chemical vapor deposition<\/em>, CVD)\u00a0valmistatud seadmete kontekstis,” selgitasid uurimuse peaautorid Amin Salehi-Khojin<\/strong> ja David Estrada<\/strong>. Teadlased leidsid, et grafeenip\u00f5histe sensorite tundlikkus s\u00f5ltub defektide t\u00fc\u00fcbist ja kujust.<\/p>\n

,,Peaaegu puhtad keemilised sensorid on anal\u00fc\u00fctmolekulide suhtes v\u00e4hem tundlikud, sest adsorbaadid kinnituvad punktdefektide k\u00fclge, millede \u00fcmbruses on madalam takistus,” \u00fctles Salehi-Khojin. ,,Selle tulemusena on adsorptsioonil punktdefektides \u00a0seadme \u00fcle\u00fcldisele takistusele v\u00e4ike m\u00f5ju. Mikromeetri suurused joondefektid v\u00f5i punktdefektidest moodustunud jooned on erinevad, sest nende \u00fcmbruses ei leidu madalama takistusega juhtivusradasid, ning seega on takistuse muutumine p\u00e4rast adsorptsiooni m\u00e4rgatav.”<\/p>\n

,,See tulemus v\u00f5ib viia paremate ja odavamate gaasisensoriteni sellistes rakendustes nagu energia, koduohutus ja meditsiinidiagnostika,” \u00fctles Estrada.<\/p>\n

Autorite s\u00f5nul p\u00f5hjustab defektidega CVD-grafeeni sensorite kahedimensionaalne olemus s\u00fcsinik-nanotorudel p\u00f5hinevate sensoritega v\u00f5rreldes teistsugust k\u00e4itumist. Tundlikkus suureneb veelgi, kui l\u00f5igata grafeen ribadeks, millede laius on joondefektide m\u00f5\u00f5tmetega v\u00f5rreldav – antud uurimuses mikromeetri skaalas.<\/p>\n

,,Me tegime kindlaks, et gaasid, millede kohalolu me sensoritega m\u00e4\u00e4rata tahtsime, kipuvad kinnituma defektide k\u00fclge,” v\u00f5ttis Pop asja kokku. ,,Grafeeni pinnadefektid on kas punkti, kortsu v\u00f5i joone sarnased. Me leidsime, et punktid olulisi erinevusi ei p\u00f5hjusta, ning et k\u00f5ige t\u00f5en\u00e4olisemalt toimub kogu asi just joonte juures.”<\/p>\n

Allikas<\/a><\/p>\n

Teadusartikkel: “Polycrystalline Graphene Ribbons as Chemiresistors<\/a>“<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Kuigi Illinoisi \u00dclikooli teadlased leidsid, et grafeenist saab valmistada \u00fclih\u00e4id keemilisi sensoreid, panid nad t\u00e4hele ka \u00fcllatavat t\u00f5siasja: sensorid on veelgi paremad, kui grafeen ise on ”halvem” – rohkem defekte t\u00e4hendab paremaid t\u00f6\u00f6omadusi. ,,See on t\u00e4iesti vastupidine sellele, mida me vajame transistorite jaoks,” s\u00f5nas Eric Pop, uurimisgrupi \u00fcks liikmetest. ,,Fakt, et mida halvem grafeen oli, […]<\/p>\n","protected":false},"author":32,"featured_media":22949,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[31,16],"tags":[45,110],"class_list":{"0":"post-22948","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-rakenduslik-teadus","8":"category-teadusuudis","9":"tag-grafeengrafaan","10":"tag-materjal","11":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/22948","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/32"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=22948"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/22948\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/media\/22949"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=22948"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=22948"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=22948"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}