Near infrared electroluminescence from neodymium complex–doped polymer light emitting diodes

Organic light emitting diode devices employing organometallic Nd(9-hydroxyphenalen-1-one)3 complexes as near infrared emissive dopants dispersed within poly(N-vinylcarbazole) (PVK) host matrices have been fabricated by spin-casting layers of the doped polymer onto glass/indium tin oxide (ITO)/3,4-polyethylene-dioxythiophene-polystyrene sulfonate (PEDOT) substrates. Room temperature electroluminescence, centered at ∼1065 nm, was observed from devices top contacted by evaporated aluminum or calcium metal cathodes and was assigned to transitions between the 4F3 / 2 → 4I11 / 2 levels of the Nd3+ ions. In particular, a near infrared irradiance of 8.5 nW/mm2 and an external quantum efficiency of 0.007% was achieved using glass/ITO/PEDOT/PVK:Nd(9-hydroxyphenalen-1-one)3/Ca/Al devices.