發(fā)布時間：2018-03-03 05:39

  本文選題：石墨烯材料　切入點：薄膜厚度　出處：《西南科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：本文采用改進Hummers法制備氧化石墨,經超聲剝離得到氧化石墨烯(GO);采用旋涂法并通過控制GO水相分散液濃度制備不同厚度GO薄膜;采用熱還原法制備不同還原程度的還原氧化石墨烯(r GO)薄膜;采用一步水熱復合法制備得到石墨烯-聚苯胺(r GO-PANI)復合材料。利用XRD、FT-IR、Raman、AFM、SEM、TG-DTA和氣敏測試系統(tǒng)等對GO、r GO和r GO-PANI的結構、形貌及氣敏性能進行表征分析,重點探究GO薄膜厚度、熱還原程度及石墨烯與聚苯胺復合質量比對氣敏性能的影響,并進一步揭示石墨烯及其復合材料的氣敏響應機理。研究結果表明,GO在成膜過程中工藝條件對元件的氣敏性能有很大影響。采用旋涂法,隨GO水相分散液濃度由1 mg/m L增加到5mg/m L,薄膜的厚度依次為18、35、65、102和139 nm。隨著薄膜厚度增大,元件的靈敏度增大,電阻變化的線性關系變差,而響應-恢復時間延長。當薄膜厚度為18 nm時濕敏元件的響應時間2 s,恢復時間8 s,靈敏度可達72.59%。隨著還原溫度的升高,GO樣品含氧官能團逐漸熱解消失,所形成的結構向較為有序的類石墨結構轉變;無序程度(ID/IG值)先由0.85增大至1.59后再減小至1.41,總體呈現(xiàn)增加趨勢;當還原溫度≤150℃樣品仍表現(xiàn)GO的性質,當還原溫度≥250℃時則表現(xiàn)出r GO的性質;還原溫度為150、200和350℃時樣品分別表現(xiàn)出p型、雙極型和n型半導體性質。在室溫下,GO及低還原程度的r GO氣敏元件對H2表現(xiàn)出較高的響應和靈敏度,靈敏度88.56%,響應時間30 s。r GO-PANI復合材料比單純的r GO、PANI的氣敏性能更加優(yōu)異,在400 ppm濃度的NH3環(huán)境下,r GO、PANI和r GO-PANI-1的靈敏度依次為13.92、41.49和50.26%。響應時間依次為422、296和156 s,恢復時間依次為485、304和214 s;隨著復合材料中PANI質量的增加,靈敏度呈現(xiàn)減小趨勢,在400 ppm濃度的NH3環(huán)境下,復合材料中r GO與PANI的質量比為1:1、1:2和1:3時的靈敏度依次為50.26、44.72和38.90%。目前,常見的石墨烯氣體傳感器結構有電阻型、場效應晶體管型(FET)、聲表面型(SAW)和石英晶體微天平型(QCM),尤其是FET型氣體傳感器因具備獨特的優(yōu)勢而迅速發(fā)展。本文對FET型結構設計初步探索,優(yōu)化設計參數(shù),可為下一步研制集成、小型和智能化的高性能氣體傳感器提供理論依據(jù)和技術指導。
[Abstract]:In this paper, graphite oxide was prepared by modified Hummers method, and graphene oxide was obtained by ultrasonic stripping, and go thin films with different thickness were prepared by spin-coating method and by controlling the concentration of go aqueous dispersion. The reduced graphene oxide (GOR) thin films with different degree of reduction were prepared by thermal reduction method, and the graphene / Polyaniline (GO-PANI) composite materials were prepared by one step hydrothermal recombination method. The structures of GOr go and r GO-PANI were studied by using XRDX FT-IR Ramanine, AFMSEMN TG-DTA and gas sensing test system, etc. The morphology and gas sensing properties were characterized and analyzed. The effects of the thickness of go film, the degree of thermal reduction and the composite mass ratio of graphene to Polyaniline on the gas sensing properties were investigated. The gas sensing response mechanism of graphene and its composites is further revealed. The results show that the process conditions of go have a great influence on the gas sensing properties of the components during the process of film formation. With the increase of go aqueous dispersion concentration from 1 mg/m / L to 5 mg / mL, the thickness of the film is 1835 / 65 / 102 and 139nm / L respectively. With the increase of the thickness of the film, the sensitivity of the component increases and the linear relationship of the resistance changes becomes worse. When the thickness of the film is 18 nm, the response time of the humidity sensor is 2 s, the recovery time is 8 s, and the sensitivity is 72.59. With the increase of the reduction temperature, the oxygen functional groups of the go sample gradually disappear. The resulting structure changed to a more ordered graphite-like structure, the degree of disorder increased from 0.85 to 1.59 and then decreased to 1.41, and the reduction temperature 鈮，

本文編號：1559777