Time-dependence of erbium(III) tris(8-hydroxyquinolate) near-infrared photoluminescence: implications for organic light-emitting diode efficiency

• Published in: Synthetic metals Vol. 138; no. 3; pp. 463 - 469
• Main Authors: Magennis, S.W., Ferguson, A.J., Bryden, T., Jones, T.S., Beeby, A., Samuel, I.D.W.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 04.07.2003; Amsterdam Elsevier Science; New York, NY
• Subjects: 8-Hydroxyquinolate; Applied sciences; Electronics; Erbium; Exact sciences and technology; OLED; Optoelectronic devices; Photoluminescence; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; OLED; Erbium; 8-Hydroxyquinolate; Photoluminescence; Performance evaluation; Radiative lifetimes; Quantum yield; Thin film; Light emitting diode; Near infrared radiation; Erbium complex; Optoelectronic device; Organic compounds
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(02)00501-5

We report the first time-resolved photoluminescence studies of erbium tris(8-hydroxyquinolate), [ErQ 3], as a powder, a thin film blend with polycarbonate, an evaporated film and in DMSO- d 6 solution. The 4 I 13/2→ 4 I 15/2 transition at 1.5 μm displays biexponential kinetics with photoluminescence lifetimes in the region of 0.2 μs for the powder, 0.4 μs for the thin film blend, 0.9 μs for the evaporated film, and 2 μs in solution. These observed lifetimes are much shorter than the natural radiative lifetimes of this Er 3+ transition, implying photoluminescence quantum yields that range from 0.002 to 0.03%. This has significant consequences for the device efficiencies achievable by near IR-emitting organic light-emitting diodes (OLEDs) containing [ErQ 3] as the emissive layer.