About 20% of electricity consumption in industrial countries is used for lighting purposes. Therefore, any efficiency increase of lighting devices has considerable positive effects both from an economical and environmental points of view, since more efficient lighting devices will decrease energy consumption and the need for conventional power plants. Presently, solid state lighting (SSL) is quickly progressing and emission efficiency of the devices increases at a very fast rate. SSL does not only offer higher efficiency with respect to conventional lighting, but by a proper choice of pump source and emitting phosphors, it is also relatively easy to fine tune the light colour temperature to match the desired application. In this communication, we report about the preparation and preliminary spectroscopic characterisation of lanthanide doped calcium thiogallates solid solutions, with composition CaxBa1-xGa2S4 (x = 0.1-1.0) [1]. The compounds were synthesized with solid-state reactions from stoichiometric amounts of CaS, BaS and Ga2S3 powders in graphitized quartz ampoules under 3?10 1 ÷ 3?10 2 Pa vacuum. The synthesis was carried out at the melting point of host matrices at 1200 °C for one hour, followed by an heat treatment at 800 °C for 4-5 hour. Activation with rare-earth ions was carried out by adding to the charge fluorides of the selected rare-earth elements. Solid solutions of different stoichiometry were doped with 3% Tm and 7% Dy at. By using LED sources (for excitation at 435 nm) and the second harmonic generation of a mode-locked Ti:Sa laser for excitation in the 360 nm region, the emission of the solid solutions was measured. In Fig. 1 a comparison of the emission spectra obtained by excitation at 365 nm of the codoped Dy/Tm samples are shown. A strong dependence from the host composition is evident.
Rare earth doped sulphide materials for white light generation
Stefano Pelli;Alessandro Cosci;Giancarlo Righini;Adolfo Speghini;
2017
Abstract
About 20% of electricity consumption in industrial countries is used for lighting purposes. Therefore, any efficiency increase of lighting devices has considerable positive effects both from an economical and environmental points of view, since more efficient lighting devices will decrease energy consumption and the need for conventional power plants. Presently, solid state lighting (SSL) is quickly progressing and emission efficiency of the devices increases at a very fast rate. SSL does not only offer higher efficiency with respect to conventional lighting, but by a proper choice of pump source and emitting phosphors, it is also relatively easy to fine tune the light colour temperature to match the desired application. In this communication, we report about the preparation and preliminary spectroscopic characterisation of lanthanide doped calcium thiogallates solid solutions, with composition CaxBa1-xGa2S4 (x = 0.1-1.0) [1]. The compounds were synthesized with solid-state reactions from stoichiometric amounts of CaS, BaS and Ga2S3 powders in graphitized quartz ampoules under 3?10 1 ÷ 3?10 2 Pa vacuum. The synthesis was carried out at the melting point of host matrices at 1200 °C for one hour, followed by an heat treatment at 800 °C for 4-5 hour. Activation with rare-earth ions was carried out by adding to the charge fluorides of the selected rare-earth elements. Solid solutions of different stoichiometry were doped with 3% Tm and 7% Dy at. By using LED sources (for excitation at 435 nm) and the second harmonic generation of a mode-locked Ti:Sa laser for excitation in the 360 nm region, the emission of the solid solutions was measured. In Fig. 1 a comparison of the emission spectra obtained by excitation at 365 nm of the codoped Dy/Tm samples are shown. A strong dependence from the host composition is evident.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
