Zou Linlin, Yu Ting, Sheng Haoyang, Chen Yeqing, Zeng Qingguang
School of Applied Physics and Materials, Wuyi University Jiangmen Guangdong 529020 P. R. China
Institute of Carbon Peaking and Carbon Neutralization, Wuyi University Jiangmen 529020 P.R. China.
RSC Adv. 2025 Apr 22;15(16):12797-12807. doi: 10.1039/d5ra00874c. eCollection 2025 Apr 16.
Upconversion (UC) nanocrystals and carbon dots (CDs) have emerged as significant subjects of research interest across various fields, including biomedicine, fluorescence sensing, and anti-counterfeiting. This study presents a novel method for preparing NaYF:Yb,Er@CDs composites through the cubic-to-hexagonal phase transformation of NaYF mediated by CDs. The formation of these composites was successfully confirmed through morphological and structural analyses. Notably, the composites were found to enhance UC emission and prolong luminescence lifetime, with these effects being dependent on the quantity of CDs used. The experimental results indicate that the enhanced UC emission in the composites is primarily due to the interception of quenching centers, such as hydroxyl (OH) groups. Furthermore, these composites with improved UC emission have the potential to serve as highly sensitive optical thermometers based on the fluorescence intensity ratio technique, with optimal green emissions at 298 K and a maximum relative sensitivity of 1.08 K. This work paves the way for advancements in UC luminescence and establishes a foundation for the design and fabrication of high-efficiency UC materials with potential applications in optical temperature sensing.
上转换（UC）纳米晶体和碳点（CDs）已成为包括生物医学、荧光传感和防伪在内的各个领域研究兴趣的重要课题。本研究提出了一种通过碳点介导的NaYF从立方相到六方相的转变来制备NaYF:Yb,Er@CDs复合材料的新方法。通过形态和结构分析成功证实了这些复合材料的形成。值得注意的是，发现这些复合材料增强了上转换发射并延长了发光寿命，这些效应取决于所用碳点的数量。实验结果表明，复合材料中增强的上转换发射主要是由于羟基（OH）基团等猝灭中心的截留。此外，这些具有改善的上转换发射的复合材料有潜力作为基于荧光强度比技术的高灵敏度光学温度计，在298 K时具有最佳的绿色发射，最大相对灵敏度为1.08 K。这项工作为上转换发光的进展铺平了道路，并为设计和制造在光学温度传感中具有潜在应用的高效上转换材料奠定了基础。
