Circadian Light Source Based on K x Na 1-x LuS 2 :Eu 2+ Phosphor

Vítězslav Jary (1) , Lubomír Havlák (1) , Jan Bárta (1, 2) , Martin Rejman (1) , Aleš Bystřicky (1) , Christophe Dujardin (3) , Gilles Ledoux (3) , Martin Nikl (1)

1 Institute of Physics [Prague]
2 FJFI CTU - Faculty of Nuclear Sciences and Physical Engineering [Prague]
3 ILM - Institut Lumière Matière [Villeurbanne]

The presented work describes a functional demonstration device representing the source of white light with tunable color correlated temperature. Tunability is achieved by using two different kinds of excitation diodes (nearUV and blue) in combination with a proper K_xNa_1-xLuS₂:Eu²⁺ phosphor. Its luminescence due to the Eu²⁺ 5d–4f allowed transition covers a broad emission region in visible range under both nearUV and blue excitations. The possibility to change the intensity ratio of the excitation diodes yields the changes of the output color correlated temperature. These changes are clearly demonstrated by shifts in the CIE color space; light quality is also quantified and discussed using CRI (color rendering index) and CQS (color quality scale) metrics.

Domaines: Matériaux

Vítězslav Jary, Lubomír Havlák, Jan Bárta, Martin Rejman, Aleš Bystřicky, et al.. Circadian Light Source Based on K x Na 1-x LuS 2 :Eu 2+ Phosphor. ECS Journal of Solid State Science and Technology, 2018, 7 (1), pp.3182 - 3188. ⟨10.1149/2.0231801jss⟩. ⟨hal-01694287⟩