Synthesis and photoluminescence characterizations of Zn2+ and Tb3+ codoped CeO2 phosphors for temperature sensing applications

Abstract

Cyan light-emitting Ce0.985-xZnxO2:0.015 Tb3+ (x = 0 to 0.2) phosphors were synthesized using the ethylenediaminetetraacetic acid-assisted hydrothermal method. The X-ray diffraction and refinement analyses of the prepared phosphors indicated that the formed face-centered cubic structure remained intact even after the doping of large quantities of Zn2+ ions. However, the incorporation of Zn2+ ions increased the Ce3+/Ce4+ ratio, resulting in the enhancement of oxygen vacancies in the prepared phosphors. The generation of oxygen vacancies caused the evolution of a broad photoluminescence emission band ranging from 400 to 525 nm with a characteristic Tb3+ emission of approximately 543 nm. Two-emission regions in Ce0.885Zn0.1O2:0.015 Tb3+ phosphors were utilized for measuring the fluorescence intensity ratio (FIR) as a function of temperature ranging from 303 to 523 K. At 523 K, the FIR values dropped to approximately 40% of the starting temperature value. The variation of FIR values followed the Boltzmann behavior. The Boltzmann fitting demonstrated the feasibility of the present phosphors for temperature sensor applications. The optimum absolute sensor sensitivity of Ce0.885Zn0.1O2:0.015 Tb3+ phosphors was measured to be 0.0043 K−1 at 398 K with a resolution of approximately 1 K−1. Moderate temperature sensitivity, negligible hysteresis loop, and excellent reversibility revealed the suitability of Ce0.885Zn0.1O2:0.015 Tb3+ phosphors for sensing the temperature in various electronic devices.