A Deep‐Blue Electroluminescent Device Based on a Coumarin Derivative. Issue 4 (15th March 2016)

• Record Type: Journal Article
• Authors: Kumar, Shiv; Puttaraju, Boregowda; Patil, Satish
• Is Part Of: ChemPlusChem. Volume 81:Issue 4(2016)
• Page Start: 384
• Page End: 390
• Publication Date: 2016-03-15
• Subjects: coumarins -- differential scanning calorimetry -- fluorescence -- organic light emitting diodes -- thermogravimetric analysis; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201500572
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: The design and synthesis is reported of 7‐(9 H ‐carbazol‐9‐yl)‐4‐methylcoumarin (Cz–Cm), comprising a carbazole donor moiety and a 4‐methylcoumarin acceptor unit, for use in a blue organic light‐emitting diode. A detailed solid state, theoretical and spectroscopic study was performed to understand the structure–property relationships. The material exhibits deep‐blue emission and high photoluminescence quantum yield both in solution and in a doped matrix. A deep‐blue electroluminescence emission at 430 nm, a maximum brightness of 292 cd m −2 and an external quantum efficiency of 0.4 % was achieved with a device configured as follows: ITO/NPD (30 nm)/TCTA (20 nm)/CzSi(10 nm)/10 wt % Cz–Cm:DPEPO (10 nm)/TPBI (30 nm)/LiF (1 nm)/Al [ITO=indium tin oxide, NPD= N, N ′‐di(1‐naphthyl)‐ N, N ′‐diphenyl‐(1, 1′‐biphenyl)‐4, 4′‐diamine, TCTA=tris(4‐carbazoyl‐9‐ylphenyl)amine, CzSi=9‐(4‐ tert ‐butylphenyl)‐3, 6‐bis(triphenylsilyl)‐9 H ‐carbazole, DPEPO=bis[2‐(diphenylphosphino)phenyl]ether oxide, TPBI=1, 3, 5‐tris( N ‐phenylbenzimidazol‐2‐yl)benzene]. Abstract : A wide band‐gap carbazole–coumarin derivative for organic light‐emitting diodes was designed and synthesized. Absorption and emission spectra of this compound in solution and in the solid state were measured. An organic light‐emitting diode was constructed using this fluorophore and a deep‐blue emission with an external quantum efficiency of 0.4 % was achieved.