Temperature and Pressure Sensing Using an Optical Platform Based on Upconversion Luminescence in NaSrY(MoO4)3 Codoped with Er3+ and Yb3+ Nanophosphors

Multifunctional materials are needed for multidimensional stimuli-sensing devices to monitor equipment in complicated working situations. Energy upconverting (UC) nanophosphors doped with rare earth ions are widely studied as materials for optical temperature and pressure sensors working via the control of fluorescence (luminescence) intensity ratio. Nonetheless, most Er3+-doped materials still have limited sensitivity of optical detection. In the present study, we attempted to develop high-sensitivity Er3+-doped sensor nanophosphors based on thermally coupled energy levels─TCLs (Stark components) for temperature and pressure sensing purposes. On the basis of different pairs of TCLs, especially those from the Stark sublevels of 2H11/2 and 4S3/2, the multiple temperature and pressure sensing performances were evaluated. The sensitivities of the pressure and temperature detection modes that are calculated using the selected Stark sublevels are noticeably greater than those based on the traditional TCLs (based on the whole bands). The findings of our study demonstrate a pioneering method for the creation of optically active, multifunctional materials and their integration into optoelectronic devices, specifically for the purpose of serving as remote sensors for low-pressure (vacuum) and -temperature measurements.