The role of the Tm3+ concentration on CaMoO4 properties processed by microwave hydrothermal under stirring condition

Author(s)

Santos Feldhaus, Carla Marina ^[1] ; Kunzel, Roseli ^[2] ; Li, Maximo Siu ^[3] ; de Azevedo Marques, Ana Paula ^[1]

Affiliation

^[1] Univ Fed Sao Paulo UNIFESP, Lab Mat Inorgan & Nanoestruturados LAMIN, Dept Quim, BR-09913030 Diadema, SP - Brazil

^[2] Univ Fed Sao Paulo UNIFESP, Dept Fis, Diadema - Brazil

^[3] Univ Sao Paulo, Inst Fis Sao Carlos, Sao Carlos - Brazil

• Document type: Journal article
• Source: Journal of the American Ceramic Society; v. 104, n. 10, p. 5192-5204, OCT 2021.
• Web of Science Citations: 0

Abstract

The compounds based on calcium molybdate (CaMoO4) 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 CaMoO4:Tm3+ phosphors synthesized by coprecipitation and processed in a microwave-hydrothermal system at low temperature (100 degrees C) and stirring. The effect of the Tm3+ doping content (0%-12%) is studied in full detail to understand their role in the CaMoO4:Tm3+ 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% Tm3+ ions. The designed phosphors have shown two emission bands in which intensity depends on the Tm3+ 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 F-3(3), H-3(4) -> H-3(6) transitions from Tm3+ ion, become more intense. The outcomes of this work reveal that appropriated Tm3+ ions doping levels can be applied to suppress the PL emission in the visible range and improve that in the near-infrared region in CaMoO4-based materials. (AU)

• FAPESP's process: 13/07437-5 - Production and characterization of nanostructures ceramic materials pure and hybrids
• Grantee: Ana Paula de Azevedo Marques
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/20578-5 - Ceramic Materials Type Scheelite: Properties and its Relations with Morphology and Dimension
• Grantee: Ana Paula de Azevedo Marques
• Support Opportunities: Regular Research Grants