掺杂石墨烯量子点的发光机理和超快过程研究

Two dimension SP2 structure of graphene and its composite structures have complex multiformities, their chemical modification, doping and tailoring of size and shape leave behind a large number of scientific problems to be resolved. Only if the breaking through of these key problems is made, the new outstanding graphene materials can then expand on many application field and lead the innovation of new.technologies. Graphene quantum dots, one of new rising luminescence materials in recent years, are the new research area of graphene, which include all the possibilty of bandgap engineering of the Graphene, especially the growing and the fabrication of the doping graphene quantum dots with high quantum yield gives the new ways to deep understand the doping mechanism and bandgap of the dopped graphenes. However the understanding of electronic structure and luminescence mechanism of graphene quantum dots is limited and blurred. The applied project will use the advance technique of ultrafast spectroscopy combined with the low temperature technique to thoroughly study the electronic level structure, luminescence mechanism and the pathway of energy transfer and relaxation of the doped graphene quantum dots. Through the studies of this model system, the applied project can help to push forward the study of graphene doping and band gap engineering-the key problem of graphene application, push forward the application of graphene quantum dots on the bio-sensing and bio-marking, OLED luminescence materials, etc.

石墨烯二维SP2结构及其复合纳米结构存在复杂的多样性，它的化学改性、掺杂和尺寸调节遗留了大量科学问题有待解决。只有在石墨烯掺杂和能带调控等关键科学问题上取得突破才能使优异的石墨烯新材料向各个应用领域渗透，引领技术革新。其中石墨烯量子点是近几年涌现的石墨烯研究新方向，包含了几乎所有石墨烯能带调控的方式，特别是高荧光量子产率掺杂石墨烯量子点的制备，为深入研究石墨烯掺杂的机理和能带带来了新途径。然而对掺杂石墨烯量子点的能带结构和发光机制的了解目前还众说纷纭、模糊不清。申请项目拟利用先进超快光谱技术和低温技术相结合对掺杂石墨烯量子点电子结构、发光机制和能量转移和耗散过程进行深入的研究，通过石墨烯量子点这一模型系统的研究，推动石墨烯掺杂和能带调控关键科学问题的解决，推动石墨烯量子点在生物荧光标记、OLED发光材料和生物传感等方面的应用。

项目围绕计划书的研究内容和目标，我们完成低温系统与共焦显微荧光系统联合的搭建，可进行可见光连续波长的荧光测试。具有超快降温、超低震动和超高的温度稳定性，温度在 4K-300K 可调，实现低温共焦显微荧光测量技术。完成了泵浦探测白光双光束系统的搭建，可进行400nm激发光泵浦，300-700nm白光探测。通过先进的超快光谱技术和低温技术来研究石墨烯量子点的掺杂形态，发光机制等，为研究制备具有不同物理和化学特性的石墨烯量子点提供技术方法。进一步地，以掺杂石墨烯量子点作为模型系统研究纳米材料体系中，掺杂能带调控的机制和途径，电子能级结构，基态和激发态特性以及超快能量传递和耗散途径等基础科学问题。在测试系统上进行了石墨烯量子点和钙钛矿材料体系的研究，在石墨烯量子点的掺杂结构和发光机理，钙钛矿材料的激射特性，极化激元和极化子耦合，和多效应发光方面取得重要进展。发表标注该项目资助的 SCI 论文 7 篇， EI 论文3篇，专利2项，其中ACS photonics 1篇，OPTICA 1 篇，Phys. Rev. A. 2篇，Optical Engineering 1篇，培养毕业硕士研究生4名，博士研究生1名。很好地完成项目预定研究目标。.另外，在本项目的支持下，开展了纳米荧光显微镜研究，相关工作发表在Optica，2019, 6, 1515，因在纳米荧光显微成像速度的突破性进展，被美国光学学会选中同步进行新闻发布(“Ghost Imaging Speeds Up Super-Resolution Microscopy--New nanoscopy approach poised to capture biological processes occurring inside cells at submilisecond speeds”)。之后，被著名物理和光学专业网站Phys.org和Photonics.com转发。