Dy<sup>3+</sup>-Assisted Negative-Thermal Quenching in Ho<sup>3+</sup>-Doped SrMoO<sub>4</sub> for Luminescence Thermometry and Lighting Applications
Vaibhav Chauhan, Prashant Dixit, Prashant Pandey, Prashant Pandey, Satyam Chaturvedi, Praveen C. Pandey, Praveen C. Pandey
Abstract
Luminescence thermometry has been a research hotspot due to its rapid response, noninvasive approach, and high spatial resolution. However, achieving good relative sensitivity with minimal temperature uncertainty remains a daunting challenge. Adding to the ongoing research, our work focuses on the luminescence thermometry application of the Dy 3+ /Ho 3+ -codoped SrMoO 4 phosphor. The negative thermal quenching in Dy 3+ emission is observed in the SrMoO 4 host. Interestingly, the codoping of Dy 3+ in SrMoO 4:Ho 3+ changes the thermal quenching behavior of Ho 3+ from positive to negative. The intriguing nature of thermal quenching of Dy 3+ and Ho 3+ in SrMoO 4 is exploited for luminescence thermometry. Due to the different responses of the Ho 3+ transitions to temperature, the relative sensitivity is calculated for three different combinations of the intensity ratio. The best sensitivity of about 0.39% K –1 at 300 K is evaluated for I Dy(572) / I Ho(541) . The repeatability measurement manifests the excellent thermal stability of the luminescence. The temperature uncertainty is found to be within 0.8 K. The Ho 3+ -doped SrMoO 4 is also probed for the lighting application. The Ho 3+ ions emit green emissions and exhibit excellent thermal stability by retaining ∼80% of their luminescence at 420 K with a 0.23 eV activation energy. The SrMoO 4:Ho 3+ phosphor exhibits excellent resistance to color drift with rising temperatures. Overall, the insights presented in our study will broaden the scope of rare-earth-doped SrMoO 4 phosphors in the fields of optical thermometry and lighting applications.