Shape-controllable synthesis of silica coated core/shell upconversion nanomaterials and rapid imaging of latent fingerprints

Upconversion material NaYF4@SiO2 in morphologies of uniform nanodumbbells, nanowires or nanorods were synthesized via a simple two-step method. The shape of the nanomaterials could be controlled by tuning the ratio of NaYF4 nanorods to silica as a result of the oriented attachment mechanism. The NaYF4@SiO2 nanodumbbells demonstrated advantage over commercial fluorescence reagents in rapid latent fingerprint imaging due to effectively circumvent luminescence quenching, high signal-to-noise ratio, and excellent photostability.