School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
Institute of Nano Science and Technology, Sector 81, Sahibzada Ajit Singh Nagar, Mohali, Punjab 140306, India.
J Phys Chem Lett. 2021 Aug 26;12(33):8080-8087. doi: 10.1021/acs.jpclett.1c02116. Epub 2021 Aug 18.
Red-emitting carbon dots (C-dots) have tremendous potential for bioimaging and optoelectronic applications. Here, we investigated the structural modification of red-emitting C-dots due to boron doping and their ultrafast relaxation dynamics. It is evident from the X-ray photoelectron spectroscopy study that the relative percentage of pyrridinic nitrogen is increased at the expense of amino nitrogen and graphitic nitrogen in B-doped C-dots. Transient absorption spectroscopy and global target analysis reveal the formation of an additional excited-state level that takes away a significant amount of the excited-state population after boron doping. This new excited state slows the initial relaxation process toward the emissive state from 317 to 750 fs and increases the overall lifetime from 1.03 to 1.45 ns in B-doped C-dots.
发红色荧光的碳点（C-dots）在生物成像和光电应用方面具有巨大的潜力。在这里，我们研究了硼掺杂导致的发红色荧光的 C-dots 的结构修饰及其超快弛豫动力学。X 射线光电子能谱研究表明，与氨基氮和石墨氮相比，硼掺杂 C-dots 中吡啶氮的相对百分比增加。瞬态吸收光谱和全局目标分析表明，硼掺杂后形成了一个额外的激发态能级，夺走了大量的激发态粒子。这个新的激发态将初始弛豫过程从 317 飞秒延长到 750 飞秒，使硼掺杂 C-dots 的整体寿命从 1.03 纳秒增加到 1.45 纳秒。
