Yan Xinxin, Li Tiesheng, Guo Linna, Li Honglei, Chen Penglei, Liu Minghua
College of Chemistry and Molecular Engineering, Zhengzhou University, The Key Lab of Chemical Biology and Organic Chemistry of Henan Province, The Key Lab of Nano-information Materials of Zhengzhou Zhengzhou 450001 P. R. China
Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 P. R. China.
RSC Adv. 2019 Apr 8;9(19):10889-10896. doi: 10.1039/c9ra01018a. eCollection 2019 Apr 3.
Pure cubic phase and uniform BiF:Ln (Ln = Ho, Er, Tm)/Yb nanoparticles (NPs) were prepared by coprecipitation. The growth mechanism of BiF:2%Er/20%Yb NPs was proposed based on evolution analysis of the time-dependent morphology, in which BiF:2%Er/20%Yb was formed through the growth process of "nucleation to crystallization and Ostwald ripening". The upconversion luminescence (UCL) properties and mechanism of BiF:Ln (Ln = Ho, Er, Tm)/Yb under dual-wavelength excitation were also systematically investigated. The emission intensity of BiF:2%Er/20%Yb by dual-wavelength excitation ( = 980 nm + 1550 nm) was 1.49 times more than that excited by 1550 nm or 980 nm individually. Furthermore, the properties of the bright white and multicolor UCL showed that yellow, purple, green, or pinkish light could be observed by controlling the doping concentration of Ln (Ln = Yb, Er, Tm, and Ho), indicating that they had potential applications in backlight sources of color displays and security labeling. The temperature sensitivity of BiF:2%Er/20%Yb exhibited a downward tendency and its max value was about 0.0036 K at 273 K. Cell toxicity tests showed that the UCNPs in phospholipid aqueous solution presented low cytotoxicity. Also, imaging and X-ray imaging revealed that the BiF:2%Er/20%Yb NPs had deep penetration and high contrast, which meant it could be used as a potential probe and contrast agent in optical bioimaging.
通过共沉淀法制备了纯立方相且均匀的BiF:Ln（Ln = Ho、Er、Tm）/Yb纳米颗粒（NPs）。基于对随时间变化的形貌的演化分析，提出了BiF:2%Er/20%Yb NPs的生长机制，其中BiF:2%Er/20%Yb是通过“成核到结晶以及奥斯特瓦尔德熟化”的生长过程形成的。还系统研究了BiF:Ln（Ln = Ho、Er、Tm）/Yb在双波长激发下的上转换发光（UCL）特性及机制。双波长激发（ = 980 nm + 1550 nm）下BiF:2%Er/20%Yb的发射强度比单独用1550 nm或980 nm激发时高1.49倍。此外，明亮的白色和多色UCL特性表明，通过控制Ln（Ln = Yb、Er、Tm和Ho）的掺杂浓度可以观察到黄色、紫色、绿色或粉红色光，这表明它们在彩色显示器的背光源和安全标签方面具有潜在应用。BiF:2%Er/20%Yb的温度敏感性呈下降趋势，在273 K时其最大值约为0.0036 K。细胞毒性测试表明，磷脂水溶液中的UCNPs具有低细胞毒性。同时，成像和X射线成像显示BiF:2%Er/20%Yb NPs具有深度穿透性和高对比度，这意味着它可作为光学生物成像中的潜在探针和造影剂。
