“…Recently, luminescent materials with different emission colors have been developed in optical, sensing, biomedical, and energy-related applications . As one kind of important inorganic luminescent materials, tungstate has been widely investigated due to the luminescent applications in diverse fields (e.g., lasers, sensors, and optical fibers). − Cadmium tungstate (CdWO 4 ) possessing monoclinic wolframite crystal structure has attracted great attention because of its many advantages such as high average refractive index, good scintillation properties, low-radiation damages, high chemical stability, and high X-ray absorption coefficient. − Therefore, extensive researches have been focused on the development of CdWO 4 for applications in X-ray detectors, phosphors, and optical devices. − As a self-activating phosphor, its luminescence is due to the charge transfer between excited O 2– 2p orbitals and the empty W 6+ 5d orbitals or structure defects. , Many efforts have been made to form CdWO 4 crystals like sol–gel, hydrothermal, molten salt, and microwave methods. − For example, the structure of CdWO 4 (e.g., monoclinic and tetragonal) can be tuned by a hydrothermal method, and the morphologies can be controlled via a sonochemical method . Furthermore, CdWO 4 can be deposited by reduced graphene oxide under hydrothermal conditions, leading to the enhancement of photocatalytic performance .…”