石墨烯量子点的制备及其在白光LED中的应用研究

发布时间：2018-06-08 16:00

  本文选题：石墨烯量子点 + 掺杂　； 参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：石墨烯量子点作为一种新型的碳纳米材料,一经发现便广受人们关注,它不仅继承了石墨烯的比表面积大等优异特性,兼具有量子点的某些特性,如量子限域效应、边缘效应、小尺寸效应等。原来带隙为零的石墨烯经切割变为量子点后,带隙被打开了,使得其在光电领域有良好的应用前景。本文主要研究掺杂型石墨烯量子点的制备,采用一步水热法分别制备出了硫氮共掺杂的石墨烯量子点(S,N-GQDs)和氯掺杂的石墨烯量子点(Cl-GQDs)。讨论分析了硫氮共掺杂和氯掺杂及不同制备参数(水热温度、水热时间、掺杂比例)对石墨烯量子点光学性能的影响。利用TEM、AFM、XPS、FTIR、Raman、XRD、PL、EL等各种表征手段对所制得的S,N-GQDs和Cl-GQDs进行分析研究。以柠檬酸为碳源,硫脲为掺杂源在水热温度160℃,水热时间6 h,柠檬酸和硫脲配比为1:4的条件下制得的S,N-GQDs,粒径均一,平均尺寸7 nm,厚度为1~2层石墨烯薄片,发光波长无明显的激发依赖性,360 nm激发下发蓝光,量子产率高达46.8%,荧光寿命可以被拟合成单指数曲线,说明S,N-GQDs是单一发色源。以β-环糊精为碳源,盐酸为氯源,在水热温度160℃,水热时间8 h,盐酸掺杂量为1.5 ml的最优条件下制备的Cl-GQDs粒径比S,N-GQDs小,平均尺寸只有1.5 nm,厚度为2~3层石墨烯薄片,发光波长有明显的激发依赖性,有两个发射峰,且发光颜色是鲜有报道的白光。将紫外光激发下发蓝光的S,N-GQDs和蓝光激发下发黄光的荧光粉YAG:Ce3+在聚乙烯醇基体中混合制备S,N-GQDs/YAG:Ce3+/PVA薄膜,当荧光粉YAG:Ce3+的掺杂量是0.1 g时,薄膜在360 nm紫外光激发下是白光,色坐标CIE(0.301,0.323),透过率高达76%,满足光电领域的应用要求。氯掺杂的石墨烯量子点(Cl-GQDs)与硅树脂复合制成Cl-GQDs/硅树脂发光薄膜。当Cl-GQDs的加入量是1 ml时,薄膜的发光强度最强,也最接近白光,此时CIE(0.28,0.33),薄膜的透过率是76%。最终分别将S,N-GQDs/YAG:Ce3+/PVA薄膜和Cl-GQDs/硅树脂薄膜与365 nm的紫外芯片结合在一起,组装成远程白光LED器件,测试器件的电致发光性能,器件的发光亮度随着注入电流的增加而增加,而器件的出光色坐标则随电流的增大而逐渐减小。此外,在不同工作电流下该远程白光LED器件的稳定性较好,满足高质量照明领域的要求。
[Abstract]:As a new kind of carbon nanomaterials, graphene quantum dots (QDs) have attracted much attention once they have been discovered. They not only inherit the excellent properties of graphene, such as large specific surface area, but also have some properties of quantum dots, such as quantum limiting effect, edge effect, etc. Small size effect, etc. After cutting into quantum dots, the band gap of graphene with zero band gap has been opened, which makes it have a good application prospect in the field of photoelectricity. In this paper, the preparation of doped graphene quantum dots (QDs) has been studied. The sulfur-nitrogen co-doped graphene quantum dots (SN-GQDs) and chlorine-doped graphene quantum dots (Cl-GQDs) have been prepared by one-step hydrothermal method. The effects of sulfur and nitrogen co-doping and chlorine doping as well as different preparation parameters (hydrothermal temperature, hydrothermal time, doping ratio) on the optical properties of graphene quantum dots were discussed and analyzed. The Sn- GQDs and Cl-GQDs were prepared by means of various characterization methods, such as Tem AFM, XPS, FTIRN, Ramande, and PLEL, etc. Using citric acid as carbon source, thiourea as dopant source, under the conditions of hydrothermal temperature 160 鈩，

本文编号：1996361