Multicolor phosphorescent organic electroluminescent element and lighting system

Abstract

This invention provides a multicolor phosphorescent organic electroluminescent element having an excellent electric power efficiency, a prolonged service life, an excellent storage stability, and an excellent stability of chromaticity against drive current, and a lighting system using the multicolor phosphorescent organic electroluminescent element. The multicolor phosphorescent organic electroluminescent element contains a plurality of phosphorescent dopants different from each other in luminescence wavelength and particularly exhibits white luminescence. Specifically, the multicolor phosphorescent organic electroluminescent element contains two or more phosphorescent dopants different from each other in luminescence wavelength and comprises two or more luminescent layers, the luminescent dopant being a phosphorescent dopant. The multicolor phosphorescent organic electroluminescent element is characterized in that at least one layer formed of luminescent layer A containing two or more phosphorescent dopants different from each other in luminescence wavelength in the same layer is provided, the content of the luminescent dopant having the highest concentration used in the luminescent layer A is not less than 4% by mass and not more than 20% by mass, and luminescent layer B having a maximum luminescence wavelength of not more than 480 nm is provided at a position near the cathode side as compared with the luminescent layer A.

Dependencies are inferred from the claim text.