Photocatalytic, thermometric and internal heating multifunctional properties of Er3+/Yb3+-codoped MoO3 upconverting microparticles

Abstract

To solve the existing challenges of luminescent materials for multifunctional applications, we developed Er3+/Yb3+-codoped MoO3 upconvering microparticles as promising platforms towards thermometry, optical heater and photocatalysis. At 980 nm light excitation, bright upconverison (UC) emissions are generated and the emission intensities are dependent on the doping content. The optimal doping content is 3 mol% and the UC emission mechanism is contributed by a tow-photon absorption process. Through analyzing the temperature-dependent UC emission intensities of thermally coupled levels of Er3+ ions, the thermometric properties of the final products are studied. The maximum absolute and relative sensitivities of the designed microparticles are 0.0093 K-1 and 2.9% K−1, respectively, which are insensitive to the dopant content. Furthermore, the laser pump power triggered internal heating properties of the developed samples are also investigated, in which the temperature of the samples is elevated from 318.7 to 587.6 K when the laser pump power is adjusted from 59 to 359 mW. Additionally, the designed microparticles can degrade pollutant efficiently upon full spectrum light irradiation. Compared with the MoO3, these compounds doped with Er3+ and Yb3+ ions show superior photocatalytic activities, in which the h+, ▪ and ·OH species can contribute to the involved photocatalytic mechanism. This work initiates a new insight to search for rare-earth ions doped upconverting materials for versatile applications.