单颗粒稀土离子掺杂纳米晶的上转换超灵敏光谱调控

Up-conversion luminescence of rare earth ions doped nanocrystals is promising for applications such as biomedical, solar cells, 3D display, sensors, etc., which is benefit from the unique spectral conversion ability. This kind of anti-Stokes transition process shows the optical tunability containing the aspects of excited state dynamics, emission wavelength, and luminescence efficiency. However, it is hard to control the spectral behavior of the Stark energy levels because of the influence from the host phonon coupling. In this proposal, the single particle based spectral technology will be applied to highly populate the excited state of luminescence centers in nano scale. The subtle control of electronic transition behavior between the Stark energy levels of rare earth ions will be realized under novel external field condition, which contains excitation power, polarization of light field, and magnetic field. Simultaneously, the luminescence dynamic process of up-conversion, and the unique spectral properties of specific electronic transitions in the saturated excitation case will be investigated to understand the physical mechanism of the interaction between external field, crystal field, and electronic transition. This could be a theoretical support for tunable emission generation of the ultrasensitive up-conversion from rare earth ions. This fine-tuning approach of up-conversion luminescence is of important significance not only for its scientific value but also for the promising applications ranging from ultrasensitive sensors to tunable laser generation.

稀土离子掺杂纳米晶的上转换发光具有独特的频谱转换能力，因此在生物医学、太阳能电池、三维显示、传感等领域具有重要的应用前景。这类发光过程在纳米尺度的调控表现出了包括激发态动力学、发射频谱、荧光效率等各方面的光学可调谐性，然而对于Stark能级间的光谱行为调控则由于基质声子耦合的影响而十分困难。本项目拟采用单颗粒光谱检测技术，使发光中心在纳米尺度处于高度受激状态，在新型外场（激发功率、光场偏振、磁场）作用下，实现对稀土离子Stark能级电子跃迁行为的精密调控。本项目拟同步开展稀土离子上转换发光在饱和激发下的光动力学过程研究，探明稀土离子特定电子跃迁的特殊光谱行为，建立外场—晶体场—电子跃迁三者间作用的物理机制，为稀土离子上转换发光的超灵敏光谱可调谐输出提供理论支持。这类超灵敏光谱的调控不仅在光物理学领域具有重要的科学价值，并且有望应用在超灵敏光学传感、可调谐激光器制造等领域。

稀土离子掺杂纳米晶的上转换发光具有独特的频谱转换能力，因此在生物医学、太阳能电池、三维显示、传感等领域具有重要的应用前景。这类发光过程在纳米尺度的调控表现出了包括激发态动力学、发射频谱、荧光效率等各方面的光学可调谐性，然而对于Stark能级间的光谱行为调控则由于基质声子耦合的影响而十分困难。本项目拟采用单颗粒光谱检测技术，使发光中心在纳米尺度处于高度受激状态，在新型外场（激发功率、光场偏振、磁场）作用下，实现对稀土离子Stark能级电子跃迁行为的精密调控。本项目拟同步开展稀土离子上转换发光在饱和激发下的光动力学过程研究，探明稀土离子特定电子跃迁的特殊光谱行为，建立外场—晶体场—电子跃迁三者间作用的物理机制，为稀土离子上转换发光的超灵敏光谱可调谐输出提供理论支持。这类超灵敏光谱的调控不仅在光物理学领域具有重要的科学价值，并且有望应用在超灵敏光学传感、可调谐激光器制造等领域。