Simultaneous Synthesis of WO 3- x Quantum Dots and Bundle-Like Nanowires Using a One-Pot Template-Free Solvothermal Strategy and Their Versatile Applications.

Tungsten oxide (WO _{3- x} ), a new alternative to conventional semiconductor material, has attracted numerous attentions owning to its widespread potential applications. Various methods have been reported for the synthesis of WO _{3- x} nanostructures such as nanowires or nanodots. However, templates or surfactants are often required for the synthesis, which significantly complicate the process and hinder the broad applications. Herein, one-pot template/surfactant-free solvothermal method is proposed to synthesize the WO _{3- x} nanostructures including fluorescent quantum dots (QDs) and bundle-like nanowires simultaneously. The as-prepared WO _{3- x} QDs can be well dispersed in aqueous medium, exhibit excellent photoluminescent properties, and show an average size of 3.25 ± 0.25 nm as evidenced by transmission electron microscopy. Meanwhile, the diameter of the WO _{3- x} nanowires is found to be about 27.5 nm as manifested by the scanning electron microscope images. The generation mechanism for these two WO _{3- x} nanostructures are systematically studied and proposed. The WO _{3- x} QDs have been successfully applied in efficient fluorescent staining and specific ferric ion detection. Moreover, the WO _{3- x} nanowires can be utilized as effective dielectric materials for electromagnetic wave absorption.
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