We report 890 nm luminescence from a neodymium-doped polymer light-emitting diode. The active layer is a blend of poly(dioctylfluorene-co-benzothiadiazole), F8BT, and a lissamine-functionalized terphenyl-based neodymium complex. We detect electroluminescence from both the lissamine (580 nm) and the Nd3+ complex (890 nm). By comparison with lissamine-free devices we show that the lissamine is crucial to infrared emission. The neodymium/lissamine luminescence intensity ratio is higher under electrical excitation than under optical excitation, showing that more triplets reach Nd3+ under electrical excitation. High turn-on voltages provide a clear indication for charge trapping onto the lissamine, and we consider direct triplet formation on the lissamine to be competing efficiently with respect to slower Dexter-type triplet transfer from the F8BT to the lissamine.

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Journal Appl. Phys. Lett.
Slooff, L.H, Polman, A, Cacialli, F, Friend, R.H, Hebbink, G.A, van Veggel, F.C.J.M, & Reinhoudt, D.N. (2001). Near-infrared electroluminescence of polymer light-emitting diodes doped with a lissamine-sensitized Nd3+ complex. Appl. Phys. Lett., 78, 2122–2124.