An investigation of the thermal sensitivity and stability of the -NaYF4:Yb,Er upconversion nanophosphors
نویسندگان
چکیده
The upconversion luminescence UCL of the hexagonal -phase NaYF4:Yb,Er nanophosphors as a function of temperature 300–450 K was examined under 978 nm light excitation. The thermal sensitivity was evaluated based on the UCL intensity ratio between H11/2– I15/2 and S3/2– I15/2 transitions RHS . Excitation power, particle sizes 37, 65, and 140 nm , ion doping concentrations, and with and without silica coating were studied. It was found that RHS is only dependent on temperature at the low excitation power, and has no direct relation with the particle size and surface effects. Silica coating was found to enhance the thermal stability significantly without altering the thermal sensitivity. © 2010 American Institute of Physics. doi:10.1063/1.3298905
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Single-step synthesis and kinetic mechanism of monodisperse and hexagonal-phase NaYF4:Yb,Er upconversion nanophosphors
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