Near-Infrared Light-Triggered Visible Upconversion Emissions in Er3+/Yb3+-Codoped Y2Mo4O15 Microparticles for Simultaneous Noncontact Optical Thermometry and Solid-State Lighting

The Er3+/Yb3+-codoped Y2Mo4O15 microparticles, which possessed admirable optical thermometric and upconversion (UC) emission behaviors, were synthesized through the traditional sintering technology of the sol-gel route. Under near-infrared (NIR) light excitation, the obtained compounds showed the featured green and red UC emissions of Er3+ ions. The most intense luminescent intensity was detected when the Yb3+ ion content was 40 mol %. Through studying the temperature-dependent UC emission intensity ratio of the monitored green emissions, the optical thermometric properties of the resultant micro-particles were investigated. The maximum sensor sensitivity of the studied microparticles with optimum doping concentration was approximately 0.00846 K-1. Moreover, the achieved maximum sensor sensitivity was independent of the dopant content that was identical with the theoretical analysis by taking advantage of the Judd-Ofelt theory. Furthermore, a significant increment in the compounds' temperature was achieved when the excitation pump power was verified in the range of 320-1040 mW. Ultimately, a green-emitting light-emitting diode device was developed with the aid of synthesized microparticles and a 940 nm NIR chip so as to identify their applicability for solid-state lighting. These aforementioned characteristics make the Er3+/Yb3+-codoped Y2Mo4O15, microparticles not only suitable for noncontacting optical thermometry but also for solid-state lighting.