Green, red, and near-infrared up-conversion emission of NaY(MoO4)(2):Er3+ submicrometric particles obtained by one-step synthesis, and its thermometric application

Lanthanide ion-based nonlinear optical processes for conversion of infrared radiation to visible radiation are well known. These processes have been used to produce efficient photonic devices for optical amplifiers in Telecom, bioimaging systems, solid-state lasers, temperature sensors, displays, and solar cells. Here, we obtained sub micrometric spherical NaY(MoO4)(2):Er3+ particles doped at 0.5, 1, 2, 5, 10, 15, and 20% (mol/mol, Er3+/Y3+ ions) by spray pyrolysis in one step, and we studied up-conversion emission as a function of the lanthanide ion content in the matrix. Characterization of the samples by XRD, FTIR, TEM, and luminescence spectroscopy confirmed that spherical particles with micro-and submicrometric diameters were produced. All the samples had tetragonal structure with space group I4(1)/a. The up-conversion studies performed upon excitation at 980 and 1550 nm confirmed a two-and three-photon mechanism, respectively. The emission behavior depended on the Er3+ content, and the materials emitted photons in the green, red, and NIR region. In addition, color emission could be tuned by the Er3+ content. Next, we studied the up-conversion behavior of the materials as a function of temperature. Spectroscopy showed that the integrated intensity emission from thermally coupled levels (H-2(11/2) and S-4(3/2)) depended linearly on temperature. The particles obtained here could be useful sensitizers for solar cells, bioimaging systems, and luminescent thermometry devices. (AU)