Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Abstract

Three new starburst DCM (4‐(dicyanomethylene)‐2‐methyl‐6‐[4‐(dimethylaminostyryl)‐4H‐pyran]) derivatives, 4,4′,4′′‐tris[2‐(4‐dicyanomethylene‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TDCM), 4,4′,′′‐tris[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TIN), and 4‐methoxy‐4′,4′′‐bis[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (MBIN), have been designed and synthesized for application as red‐light emitters in organic light‐emitting diodes (OLEDs). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) reveal their extremely high glass‐transition temperatures and decomposition temperatures, as well as their low tendency to crystallize. Photoluminescence and electroluminescence measurements show that they exhibit a greatly restricted concentration‐quenching effect compared to DCM1 (4‐(dicyanomethylene)‐2‐methyl‐6‐[p‐(N,N‐dimethylamino)‐styryl]‐4H‐pyran), a simple but typical DCM‐type dye, as a result of their non‐planar, three‐dimensional structures that result from their unique propeller‐like triphenylamine electron‐donating cores. The peripheral electron‐withdrawing moieties also play a key role in the restriction of concentration quenching. That is, TIN and MBIN, bearing 1,3‐indandione acceptors, emit more efficiently than TDCM and DCM1, which have dicyanomethylene as acceptors at a high doping concentration of 10 wt.‐% in poly(9‐vinylcarbazole) (PVK) film, irrespective of whether they are photoexcited or electroexcited, though their fluorescence quantum yields in dilute solutions are much lower than that of DCM1. By way of the co‐doping approach, the electroluminescence device with the configuration indium tin oxide (ITO)/PVK:MBIN(10 wt.‐%):tris(4‐(2‐phenylethynyl)‐phenyl)amine (TPA; 30 wt.‐%) (70 nm)/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline (BCP; 20 nm)/tris(8‐quinolinolato) aluminum (Alq3;15 nm)/LiF (0.3 nm)/Al (150 nm) exhibits a turn‐on voltage of 5.1 V, a maximum luminance of 6971 cd m–2, a maximum efficiency of 6.14 cd A–1 (405 cd m–2), and chromaticity coordinates of (0.66,0.33). The encouraging electroluminescence performance suggests potential applications of the starburst DCM red‐light emitters in OLEDs.

Amplified Spontaneous Emission (ASE) Properties of a laser dye (LD-473) in solid state

“…4c and 2). It can be seen that, when the concentration was increased, the ASE intensity quenched due to the intermolecular interaction [19,20] the ASE intensity was changed inversely with the concentration. LD-473 in MMA at a concentration of 1.8 mM was studied under identical operating conditions.…”

Red-emitting fluorescent organic light emitting diodes with low sensitivity to self-quenching

“…(1)* , S.Chenais (1) , D.Tondelier (2) , B.Geffroy (2) , I.Gozhyk (3) , M.Lebental (3) , and E.Ishow (4) ( …”

Synthesis and Physical Properties of Red Luminescent Glass Forming Pyranylidene and Isophorene Fragment Containing Derivatives

“…Then following an acidic treatment gives 2-tert-butyl-6-methyl-4H-pyran-4-one (compound 13 in Fig.4). However this method has a drawback because two synthetic reactions towards our target compound had low yields (30-40%), which results in a very low overall yield for synthesis of 2-tert-butyl-6-methyl-4H-pyran-4-one (compound 13 in Fig.4 Fortunately, there is another method for synthesizing 2-tert-butyl-6-methyl-4H-pyran-4-one (compound 13 in Fig.4) with good yields [7] using pentane-2,4-dione (compound 14 in Fig.5) as starting reactant.…”

“…One of the most preferred 2,6-disubstituted-4H-pyran-4-ones is 2-tert-butyl-6-methyl-4H-pyran-4-one (compound 13 in Fig.4) [7,11,35]. The first synthesis method starts from 3,3-dimethylbutan-2-one (compound 9 in Fig.4).…”

“…Many different structures of electron donor fragments are introduced (compounds 45-57 in Fig.13) in the pyranylidene backbone after introducing the electron acceptor fragment [1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][27][28][29]31]. In cases where only one methyl group reacts with the aldehyde, a mono-styryl derivative of pyranylidene is obtained (see Fig.13).…”