淀粉基荧光碳点的快速绿色制备及其在白光LED中的应用

摘要

以土豆淀粉为碳源,采用简单、环保的微波辅助水热法合成荧光碳点(CDs).通过实验参数优化,合成CDs的最优反应时间、反应温度和淀粉溶液浓度分别为30 min、220℃和1 mg/mL.为了提高CDs的荧光量子产率,在以上最优反应条件下,通过加入氮掺杂剂乙二胺合成氮掺杂碳点(N-CDs),其荧光量子产率(Qy)比CDs的Qy提高将近一倍.CDs与N-CDs均具有良好的水溶性和热稳定性,其溶液在紫外灯照射下均发出蓝色荧光,并且N-CDs的荧光强度明显高于CDs.再将CDs/淀粉复合物和N-CDs作为荧光粉,与紫外芯片结合得到白光发光二极管器件,器件分别发出黄白光和白光,色坐标分别为(0.38,0.45)和(0.33,0.35).淀粉基碳点荧光粉在光电器件领域表现出很大的潜力.%A simple and green synthesis of fluorescent carbon dots (CDs) was achieved by a microwave-assisted hydrothermal method using potato starch as the carbon source.CDs with a maximum quantum yield of 2.46％ were prepared by hydrothermal treatment of a 1 mg/mL starch solution at 220 ℃ for 30 min.Nitrogen doped CDs (N-CDs) were obtained under the same conditions using starch and ethylenediamine as the carbon and nitrogen sources,respectively,and their quantum yield was twice that of the undoped CDs.Both the CDs and N-CDs exhibit excellent water solubility and good thermal stability,emit blue fluorescence under UV light,but the fluorescent intensity of the latter is obviously higher than that of the former.Two white light-emitting diodes using the CD/starch composite and N-CDs as the phosphors emit yellowish white light and white light,respectively with xy coordinates of (0.38,0.45) and (0.33,0.35) in the Chromaticity Diagram of the Commission Internationale de L'Eclairage,suggesting that they have great potential application in optoelectronic devices.