The role of the Tm 3+ concentration on CaMoO 4 properties processed by microwave hydrothermal under stirring condition

The compounds based on calcium molybdate (CaMoO 4 ) are the subject of extensive research due to their excellent optical properties and a broad range of potential technological applications. In this work, we report a systematic study of CaMoO 4 :Tm 3+ phosphors synthesized by coprecipitation and processed in a microwave‐hydrothermal system at low temperature (100°C) and stirring. The effect of the Tm 3+ doping content (0%–12%) is studied in full detail to understand their role in the CaMoO 4 :Tm 3+ morphological, structural, and luminescent properties. The X‐ray diffraction, Raman, and Fourier Transform Infrared spectroscopic techniques revealed that all the prepared powders have a tetragonal crystal structure with a distinct density of cation vacancies and structural disorders. The band gap remains almost constant for doping levels lower than 8%, but it narrows strongly for powders doped with 12% Tm 3+ ions. The designed phosphors have shown two emission bands in which intensity depends on the Tm 3+ ions doping level. For doping levels lower than 2%, the photoluminescence profile displays a broad emission band peaking at 543 nm (green). For concentrations higher than 4%, the band centered at 543 nm decreases in intensity and the near‐infrared emission band at around 800 nm, assigned to 3 F 3 , 3 H 4  →  3 H 6 transitions from Tm 3+ ion, become more intense. The outcomes of this work reveal that appropriated Tm 3+ ions doping levels can be applied to suppress the PL emission in the visible range and improve that in the near‐infrared region in CaMoO 4 ‐based materials.