Athulprasad A J, Rekha S, Ramya M, Ramanarayanan Rajita
Department of Physics, Government Victoria College, University of Calicut, Palakkad, Kerala, 678001, India.
Department of Physics, Maharaja's College, Ernakulam, Kerala, 682011, India.
J Fluoresc. 2025 May 2. doi: 10.1007/s10895-025-04334-7.
Environmentally benign biosynthesized carbon dots with diverse chemical and physical properties play an important role in today's scientific research. In the present study, a new approach utilizing dye extraction from betel leaf, followed by a rapid, additive-free dye-derived-hydrothermal process, to synthesize carbon dots with a high quantum yield. The synthesized carbon dots were characterized using UV-visible, Photoluminescence (PL), Fourier transform infrared (FTIR), Raman, and X-ray photoelectron spectroscopy. The UV-visible spectrum of the carbon dot exhibited two major peaks at 233 nm and 294 nm and a tail continuing into the value 342 nm corresponding to π→π* and n→π* transitions. The PL spectra for different excitation wavelengths exhibit a broad peak at 465 nm, attributed to the carbon dot's surface defect state. FTIR spectra confirmed the presence of various functional groups present in the sample. The formation of carbon dots with an average diameter of 3.4 nm was confirmed by transmission electron microscopy (TEM) images. Energy-dispersive X-ray (EDAX) analysis showed the presence of elements C and O in the prepared sample. The synthesized carbon dots with low toxicity, strong fluorescence, and excellent photostability demonstrate immense potential as biocompatible fluorescent ink in future security applications.
具有多种化学和物理性质的环境友好型生物合成碳点在当今的科学研究中发挥着重要作用。在本研究中，采用了一种新方法，即从槟榔叶中提取染料，然后通过快速、无添加剂的染料衍生水热法来合成具有高量子产率的碳点。使用紫外可见光谱、光致发光（PL）、傅里叶变换红外光谱（FTIR）、拉曼光谱和X射线光电子能谱对合成的碳点进行了表征。碳点的紫外可见光谱在233nm和294nm处呈现两个主要峰，并且有一条尾巴延伸到342nm处，对应于π→π和n→π跃迁。不同激发波长下的PL光谱在465nm处呈现一个宽峰，这归因于碳点的表面缺陷态。FTIR光谱证实了样品中存在各种官能团。通过透射电子显微镜（TEM）图像证实了平均直径为3.4nm的碳点的形成。能量色散X射线（EDAX）分析表明制备的样品中存在元素C和O。合成的具有低毒性、强荧光和优异光稳定性的碳点在未来的安全应用中作为生物相容性荧光墨水显示出巨大潜力。
