Near-ultraviolet light induced visible emissions in Er3+-activated La2MoO6 nanoparticles for solid-state lighting and non-contact thermometry

- The optimal doping concentration for Er3+ ions in La2MoO6 host lattice was 2 mol%.
- A green-emitting LED based on the resultant nanoparticle and NUV chip was fabricated.
- The maximum sensitivity for the synthesized nanoparticle was 0.0097 K−1 at 463 K.
- The sensitivity of the studied samples was dependent on the dopant concentration.
- The obtained nanoparticles possessed superior water resistance behavior.

Series of Er3+-activated La2MoO6 nanoparticles were prepared by a traditional sol-gel method. Under the excitation of 379 nm, the resultant compounds revealed dazzling emissions that can be seen by naked eye. With the increment of Er3+ ion concentration, the emission intensity showed an upward tendency and reached its maximum value when the doping concentration was 2 mol%. The critical distance was calculated to be 23.41 Å and the dipole-dipole took the domination in the concentration quenching mechanism. Furthermore, by means of a fluorescence intensity ratio technique, the temperature sensing performances of the synthesized samples in the temperature range of 303-463 K were investigated based on the thermally coupled levels, 2H11/2 and 4S3/2, of Er3+ ions. It is found that the sensor sensitivity of Er3+-activated La2MoO6 nanoparticles can be greatly affected by the doping concentration and the maximum sensor sensitivity was determined to be about 0.0097 K−1 at 463 K. In addition, the prepared nanoparticles also exhibited splendid water resistance behaviors. These results demonstrate that the Er3+-activated La2MoO6 nanoparticles are promising candidates for simultaneous solid-state lighting and non-contact thermometry.

EL spectrum of the fabricated green-emitting LED device and sensor sensitivity as a function of temperature. Inset shows the digital images of the fabricated device as well as the schematic diagram for the fabrication of green-emitting LED device.94