Multifunctional Eu(3+)- and Er(3+)/Yb(3+)-doped GdVO(4) nanoparticles synthesized by reverse micelle method

Synthesis of Eu(3+)- and Er(3+)/Yb(3+)-doped GdVO(4) nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu(3+)-doped GdVO(4) nanoparticles emit red light through downconversion upon UV excitation. Er(3+)/Yb(3+)-doped GdVO(4) nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from (2)H(11/2) → (2)I(15/2) and (4)S(3/2) → (4)I(15/2) transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K(−1), which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.