Yan Long, Huang Jinshu, An Zhengce, Zhang Qinyuan, Zhou Bo
State Key Laboratory of Luminescent Materials and Devices, Institute of Optical Communication Materials, and Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, South China University of Technology, Guangzhou 510641, People's Republic of China.
Nano Lett. 2022 Sep 14;22(17):7042-7048. doi: 10.1021/acs.nanolett.2c01931. Epub 2022 Jul 14.
Thermal activation of upconversion luminescence in nanocrystals opens up new opportunities in biotechnology and nanophotonics. However, it remains a daunting challenge to achieve a smart control of luminescence behavior in the thermal field with remarkable enhancement and ultrahigh sensitivity. Moreover, the physical picture involved is also debatable. Here we report a novel mechanistic design to realize an ultrasensitive thermally activated upconversion in an erbium sublattice core-shell nanostructure. By enabling a thermosensitive property into the intermediate I level of Er through an energy-migration-mediated surface interaction, the upconverted luminescence was markedly enhanced in the thermal field together with a striking thermochromic feature under 1530 nm irradiation. Importantly, the use of non thermally coupled red and green emissions contributes to the thermal sensitivity up to 5.27% K, 3 times higher than that obtained by using conventional thermally coupled green emissions. We further demonstrate that the controllable surface interaction is a general approach to the thermal enhancement of upconversion for a series of lanthanide-based nanomaterials. Our findings pave a new way for the development of smart luminescent materials toward emerging applications such as noncontact nanothermometry, information security, and anticounterfeiting.
纳米晶体中热激活上转换发光为生物技术和纳米光子学带来了新机遇。然而，要在热场中实现对发光行为的智能控制，使其具有显著增强和超高灵敏度，仍然是一项艰巨的挑战。此外，其中涉及的物理图景也存在争议。在此，我们报道了一种新颖的机理设计，以在铒亚晶格核壳纳米结构中实现超灵敏热激活上转换。通过能量迁移介导的表面相互作用，使铒的中间I能级具有热敏特性，在热场中，上转换发光显著增强，并且在1530nm照射下呈现出显著的热致变色特性。重要的是，使用非热耦合的红色和绿色发射，热灵敏度高达5.27% K，比使用传统热耦合绿色发射获得的灵敏度高出3倍。我们进一步证明，可控的表面相互作用是一系列镧系基纳米材料热增强上转换的通用方法。我们的发现为开发用于非接触式纳米测温、信息安全和防伪等新兴应用的智能发光材料铺平了新道路。
