CdS/ZnS quantum dots and CaAl2Si2O8 phosphor hybrid white LED

Core/shell CdS/ZnS quantum dots (QDs) with the emission wavelength of 618nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. CaAl₂Si₂O₈:Eu²⁺, Mn²⁺ phosphor was synthesized by high-temperature solid state reaction at 1290°C for 2 hours under the H₂ reducing atmosphere, and X-ray powder diffraction analysis confirmed the formation of it. It has two emission bands peaking at 420 nm and 580nm originated from the transition 5d to 4f of Eu²⁺ and ⁴T₁-⁶A₁ of Mn²⁺, respectively. Blends of CaAl₂Si₂O₈:Eu²⁺, Mn²⁺ phosphor and CdS/ZnS QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of CaAl₂Si₂O₈:Eu²⁺, Mn²⁺ phosphor and QDs with a weight ratio of 2:1, with the CIE coordinate of (0.3183, 0.3036) and CRI of 85 was obtained.