Efficient solid-state and dual-mode photoluminescence of carbon-dots/NaLuF4 microcrystals for multifunctional applications

The carbon-dots/NaLuF4 microcrystals have been synthesized by the hydrothermal method and bright blue emission from carbon dots is observed in aqueous and solid state under 365 nm excitation. Self-quenching property of the carbon-dots/NaLuF4 microcrystals under solid state was deeply investigated, by changing the ratio of citric acid (CA) and ethylenediamine (DHE). The results indicate that the carbon dots can be effectively adsorbed and dispersed on the surface of NaLuF4 microcrystals, suppressing the aggregation of carbon dots. Furthermore, the upconversion luminescence can also be realized under 980 nm laser excitation. From the above observations, the carbon-dots/NaLuF4 microcrystals not only reveal emission property of carbon dots and NaLuF4, respectively, but also optimize the property of carbon dots. It provides a promising new strategy to prevent the carbon dots quenching in solid state and the carbon-dots/NaLuF4 microcrystals may have potential multi-applications in different fields including temperature sensing, solid-state display lighting as well as security inks.