Simultaneous Synthesis of WO3−x Quantum Dots and Bundle‐Like Nanowires Using a One‐Pot Template‐Free Solvothermal Strategy and Their Versatile Applications

Tungsten oxide (WO3−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 WO3−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 WO3−x nanostructures including fluorescent quantum dots (QDs) and bundle‐like nanowires simultaneously. The as‐prepared WO3−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 WO3−x nanowires is found to be about 27.5 nm as manifested by the scanning electron microscope images. The generation mechanism for these two WO3−x nanostructures are systematically studied and proposed. The WO3−x QDs have been successfully applied in efficient fluorescent staining and specific ferric ion detection. Moreover, the WO3−x nanowires can be utilized as effective dielectric materials for electromagnetic wave absorption.