Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices |
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Authors: | Matteo Mauro Elsa Quartapelle Procopio Yinghui Sun Chen‐Han Chien Daniela Donghi Monica Panigati Pierluigi Mercandelli Patrizia Mussini Giuseppe D'Alfonso Luisa De Cola |
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Affiliation: | 1. Dipartimento di Chimica Inorganica Universitá degli Studi di Milano Metallorganica e Analitica “L. Malatesta” Via Venezian 21, 20133 Milano (Italy);2. Westf?lische Wilhelms Universit?t Münster Physikalisches Institut Mendelstrasse, 7 48149 Münster, Germany and Center for Nanotechnology (CeNTech) 48149 Münster (Germany);3. Department of Applied Chemistry National Chiao Tung University Hsinchu, 30056 (Taiwan);4. Dipartimento di Chimica Strutturale e Stereochimica Inorganica Universitá degli Studi di Milano Via Venezian 21, 20133 Milano (Italy);5. Dipartimento di Chimica Fisica ed Elettrochimica Universitá degli Studi di Milano Via Golgi 19, 20133 Milano (Italy) |
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Abstract: | A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) is reported. These compounds, of general formula Re2(µ‐Cl)2(CO)6(µ‐1,2‐diazine)], contain diazines bearing alkyl groups in one or in both the β positions. Their electrochemical and photophysical properties are presented, as well as a combined density functional and time‐dependent density functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess high emission quantum yields (? = 0.18–0.22 for the derivatives with disubstituted diazines). In butyronitrile glass, at 77 K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is observed, accompanied by a strong increase in the lifetime values. The highest‐performing emitting complex, containing cyclopentapyridazine as ligand, is tested in a polymer‐based light‐emitting device, with poly(9‐vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7‐bis(diphenylphosphine oxide)‐9‐(9‐phenylcarbazol‐3‐yl)‐9‐phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is solution processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes. |
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Keywords: | DFT computations organic light‐emitting diodes rhenium complexes |
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