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

The Er 3+ /Yb 3+ -codoped Y 2 Mo 4 O 15 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 Er 3+ ions. The most intense luminescent intensity was detected when the Yb 3+ 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 microparticles 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 Er 3+ /Yb 3+ -codoped Y 2 Mo 4 O 15 microparticles not only suitable for noncontacting optical thermometry but also for solid-state lighting.