基于金属纳米光学结构的远程荧光粉白光LED发光效率的调控机理研究

Remote phosphor white LED is emerging as a competing technology in LED lighting application, due to its homogenous distribution of the luminescence, stability and lower packaging cost. Efficient white LED is achieved by improving conversion efficiency of phosphor and light extraction efficiency. The mission of this proposed project is to solve such a challenging problem, i.e., improving lighting efficiency of LED, by applying newly developed technologies in nanophotonics. We will investigate the near field coupling between the nanophotonic structure and the phosphor medium, as well the far field emission pattern of the whole coupled system. We intend to study the coupling mechanism among lattice, waveguide, and the emitters, and optimize nanophotonic structures to improve the overall efficiency. We expect that the research result from the project is of relevance to LED lighting technology, and to controlling light matter interaction using nanophotonic approach in fundamental science.

远程荧光粉白光LED有着发光均匀，稳定性好，封装成本低的优点，逐渐成为一种具有竞争力的白光LED照明技术。实现高效率的白光LED照明技术，必须提高LED荧光粉的能量转换效率和LED发光的出射效率。本项目将研究如何运用金属纳米光学结构提升远程荧光粉白光LED的发光效率，着重研究金属结构对荧光粉层的近场耦合效应，以及对LED出射光远场波瓣图的调制。通过优化设计纳米光子学结构，实现LED发光效率，显色指数和出射光的均匀性等关键性能指标的提升。项目的预期成果对于推动运用纳米光子学的技术手段来控制光与物质相互作用，提升白光LED发光效率的机理研究有着重要意义。

LED目前已经发展成为较为实用的技术。目前白光LED普遍采用的远程荧光粉技术，其中也存在荧光粉材料的转换效率及出射效率的问题。本项目着重从理论、仿真及实验的角度尝试去理解荧光粉LED的吸收、辐射及出射过程，在此基础上尝试优化提高白光LED的能量转换效率和出射效率，为今后发展高效率白光LED提供技术支撑。在本项目中，提出了一个广义电磁偶极子模型，能够快速的仿真计算LED的辐射。基于GaN LED，我们实验研究了金属纳米颗粒对LED内量子效率的提升，最大达2.3倍。