A red light-emitting ionic europium (III) complex applied in near UV LED

- We report a stable Eu3+ ternary complex with terpyridine-functionalized ionic liquid as one of the ligands.
- The thermo- and photo-stability of the complex improved significantly compared with Eu(TTA)3⋅2H2O.
- We fabricate the red-LED by coating the phosphors onto near-UV InGaN-based ultraviolet chips.

A stable europium (III) ternary complex denoted as Eu(TTA)3-tpyIL was obtained by the coordination of Eu(TTA)3·2H2O to a terpyridine-functionalized ionic liquid. The luminescent properties were investigated at room temperature. From the studies of thermo-and photo-stability, compared with the Eu(TTA)3·2H2O, both emission intensity and luminescence decay based on the complex was almost no significant decrease after enduring high temperature and long-term UV irradiation. Then red-light-emitting diodes (LEDs) were fabricated by coating complexes onto 370 nm-emitting InGaN chips. The light emission from the InGaN chips could be completely absorbed in the spectra of LED. The chromaticity coordinates of them were calculated from emission spectra and show in CIE color diagram. All these results indicate that the Eu(III) complex is promising as phosphor for fabrication of WLEDs.

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