Rare earth doped CaWO4 and CaMoO4 thin films for white light emission

Abstract

Crystalline thin films of Eu, Dy, and Er-doped CaWO4 and CaMoO4 of thicknesses 100–150 nm were synthesized by pulsed laser deposition on fused silica substrates. The atomic force and scanning electron microscopy studies confirm uniform and dense surface morphology of the samples. Tetragonal CaWO4 films show preferred growth of crystallites of (112) orientation. CaMoO4 shows texturing of crystallites of (004) orientation, while (112) crystallites are favored upon doping with rare earth ions. CaWO4 has a higher optical bandgap (5.0–5.2 eV) than CaMoO4 (3.6–4.4 eV), and both materials show blue light emission with stronger luminescence in molybdate samples. Eu doped CaWO4 and CaMoO4 produce red light emission, while Er-doped samples emit green light. The samples 1 mol.% Dy2O3–CaWO4 and 2 mol.% Eu2O3–5 mol.% Dy2O3–CaWO4 exhibit white light emission properties.

Tunable Broadband NIR PL Emissions with (Nd3+/Er3+) Codoped TiO2 via Synergetic Energy Transfer

“…As a result, finding a suitable host can be a challenge. Numerous semiconducting materials such as SnO 2 , ZnO, AWO 4 (A= Ca, Ba, Sr), TiO 2 , and MoS 2 have been used as hosts for the rare-earth ions. ,− Among them, TiO 2 has received attention due to its excellent photostability, nontoxicity, environmentally friendly nature, and inexpensive manufacturing cost. − The optimal doping concentrations of Nd­(III) and Er­(III) trivalent ions can effectively induce advantageous structural, spectroscopic transformations in the titania Ti­(IV). Herein, we propose a broad, tunable NIR PL emission by Er/Nd-doped TiO 2 .…”