Multicolored and white-light phosphors based on doped GdF3 nanoparticles and their potential bio-applications

• Published in: Journal of colloid and interface science 2012-02, Vol.367 (1), p.161-170
• Main Authors: Sayed, Farheen N., Grover, V., Sudarsan, V., Pandey, B.N., Asthana, A., Vatsa, R.K., Tyagi, A.K.
• Format: Article
• Language: English
• Subjects: breast neoplasms; Breast Neoplasms - diagnosis; Cell Line; Chemistry; Colloidal state and disperse state; color; confocal microscopy; energy efficiency; energy transfer; ethylene glycol; Exact sciences and technology; fluorescence; Fluorides - chemistry; gadolinium; Gadolinium - chemistry; Gadolinium fluoride; General and physical chemistry; Humans; ions; Luminescence; Luminescent Agents - chemistry; nanocrystals; Nanofluoride; nanoparticles; Nanoparticles - chemistry; Nanoparticles - ultrastructure; neoplasm cells; optical properties; Phosphors; Phosphorus - chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; solvents; temperature; white light; X-Ray Diffraction
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2011.09.083

[Display omitted] ► Synthesis of readily redispersible GdF3 nanoparticles by low-temperature route. ► Stabilization of hexagonal polytype of GdF3. ► White-light-emitting phosphor with CIE co-ordinates very close to broad daylight. ► Binding of nanoparticles to MCF-7 cells resulted in intense emission from cells. Rare-earth-doped gadolinium fluoride nanocrystals were synthesized by a single step synthesis employing ethylene glycol as solvent. Based on X-ray diffraction studies, stabilization of hexagonal modification of GdF3 has been inferred. The microscopic studies show formation of uniformly distributed nanocrystals (∼15nm). The nanoparticles are readily dispersible in water and show bright luminescence in colloidal solution. The luminescence properties have been investigated as a function of activator concentrations, and enhanced optical properties have been attributed to efficient energy transfer from the Gd3+ to the activator RE3+ ions, which has further been confirmed by steady-state and time-resolved optical studies. It has been demonstrated that on doping appropriate amount of activators in host GdF3, a novel white-light-emitting phosphor is obtained with CIE co-ordinates and correlated color temperature (CCT) very close to broad daylight. This can have promising applications as phosphor for white-light ultraviolet-light-emitting diodes (UV-LEDs). Our experiments showed efficient labeling of human breast carcinoma cells (MCF-7) by Tb3+-doped GdF3 nanoparticles. The fluorescence intensity was found to be dependent on the surface modifying/coating agent, and the results were validated using confocal microscopy in terms of localization of these functionalized nanoparticles.