Preparation and optical properties of HgWO₄ nanorods by hydrothermal method coupled with ultrasonic technique

Abstract

For the first time, a newly luminescent nanomaterial, monoclinic wolframite-type HgWO₄ nanorods (diameter: ∼200 nm; length: ~2000 nm) are prepared by hydrothermal method together with ultrasonic technique. Fluorescent (FL) and UV–Vis results both show that for HgWO₄, ultrasonic irradiation procedure will change its optical behaviors greatly. When the crystals become into nanorods, the fluorescent emitting peaks (365 and 495 nm) shift to central region, and finally form a wider one at 435 nm. Similar results of UV–visible absorption peaks are observed for these two products. FTIR spectra further characterize their structure. All above unique optical performances might result from both small sizes caused by ultrasonic irradiation procedure and involvement of incompact d¹⁰ electrons. Moreover, possible synthesis mechanisms of HgWO₄ nanorods are also investigated.