School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
ACS Appl Mater Interfaces. 2013 Aug 28;5(16):7875-80. doi: 10.1021/am401837h. Epub 2013 Aug 13.
Multifunctional materials exhibiting photon upconversion show promising applications for biological imaging and sensing. In this study, we examine the solid-state upconversion emission of NaYF4:Yb,Er nanoparticles in the presence of iron oxide nanoparticles. Fe3O4 nanoparticles (6 nm) were mixed with NaYF4:Yb,Er nanoparticles (either 10 or 50 nm) in varying proportions by drying chloroform solutions of nanoparticles onto glass slides. Upconversion spectra were acquired, and a laser power-dependent emission was observed and correlated with the iron oxide content in the mixture. Changes in the lattice temperature of the upconverting particles were monitored by careful observation of the relative intensities of the (2)H11/2 and (4)S3/2 →( 4)I15/2 transitions. The emission characteristics observed are consistent with an iron oxide-induced thermal effect that is dependent on both the laser power and the proportion of iron oxide. The results highlight that the thermal effects of mixed nanoparticle systems should be considered in the design of luminescent upconverting hybrid materials.
具有光子上转换功能的多功能材料在生物成像和传感方面具有广阔的应用前景。在本研究中，我们研究了氧化亚铁纳米颗粒存在下的 NaYF4:Yb,Er 纳米颗粒的固态上转换发射。通过将纳米颗粒的氯仿溶液干燥到载玻片上，将 Fe3O4 纳米颗粒（6nm）与 NaYF4:Yb,Er 纳米颗粒（10nm 或 50nm）以不同的比例混合。获得了上转换光谱，并观察到与混合物中氧化铁含量相关的激光功率依赖的发射，并对其上转换粒子晶格温度的变化进行了监测，通过仔细观察（2）H11/2 和（4）S3/2→（4）I15/2 跃迁的相对强度。观察到的发射特性与氧化铁诱导的热效应一致，该效应取决于激光功率和氧化铁的比例。结果表明，在设计发光上转换混合材料时，应考虑混合纳米粒子系统的热效应。
