Process Intensified Synthesis of Rare-Earth Doped β-NaYF4 Nanorods toward Gram-Scale Production

We reported the process intensified synthesis of β-NaYF4 nanorods based on the traditional hydrothermal methods. A high-gravity rotating packed bed (RPB) reactor was used to intensify the mass transfer and micromixing of the precursors for critical nuclei. The proposed high gravity RPB assisted strategy is easy-to-perform for scale-up. The influence of reaction conditions was explored and the possible mechanism of the formative of β-NaYF4 nanorods was discussed. Accordingly, over 1 g of pure β-phase NaYF4:Gd3+/Yb3+/Er3+ nanorods with well-defined morphology and structure were prepared via one batch reaction. The rare-earth doped β-NaYF4 nanorods are highly dispersible in organic solvents with intense upconversion luminescence under near-infrared (NIR) light irradiation. The translucent NIR detector card of nanocomposites of poly(methyl-methacrylate) and the nanoroads was fabricated accordingly. The photosensitive region can also be activated by illuminating the back of the card, which is useful when aligning two beams to overlap.