We present a new intensely phosphorescent Pb(II) coordination polymer (1) containing a heteroatomic ligand. It has a quantum yield of 21.62% and a lifetime of 25.46 µs. The naked-eye solid-state...

Herein, new deep-blue triplet-triplet annihilation (TTA) molecules, namely 4-(10-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)anthracen-9-yl)benzonitrile (TPIAnCN) and 4-(12-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)chrysen-6-yl)benzonitrile (TPIChCN), are designed, synthesized, and investigated as emitters for organic light-emitting diodes (OLED). TPIAnCN and TPIChCN are composed of polyaromatic hydrocarbons of anthracene (An) and chrysene (Ch) as the cores functionalized with tetraphenylimidazole (TPI) and benzonitrile (CN) moieties, respectively. The experimental and theoretical results verify their excellent thermal properties, photophysical properties, as well as electrochemical properties. Particularly, their emissions are in the deep blue region, with TTA emissions being observed in their thin films. By utilization of these molecules as emitters, deep blue TTA OLEDs with CIE coordinates of (0.15, 0.05), high external quantum efficiency of 6.84%, and high exciton utilization efficiency (ηs) of 48% were fabricated. This result manifests the potential use of chrysene as an alternate building block to formulate new TTA molecules for accomplishing high-performance TTA OLEDs.

Herein, we report the synthesis and characterization of an efficient ambipolar charge-carrier-transporting deep-red fluorophore (TPECNz) based on donor-acceptor-donor (D-A-D) type molecule and its application as a non-doped emitter in an organic light-emitting diode (OLED). TPECNz contains naphtho[2,3-c][1,2,5]thiadiazole (Nz) as a strong acceptor unit symmetrically functionalized with N-(4-(1,2,2-triphenylvinyl)phenyl)-carbazole as a donor and aggregation-induced emission (AIE) luminogen. The experimental (solvatochromic and emission in THF-water mixture studies) and theoretical investigations prove that TPECNz retains cooperative hybridized local and charge transfer (HLCT) and AIE features. Thanks to its D-A-D type structure with a proper twist angle between D and A units, a strong electron deficiency of Nz unit, and electron donating and hole-transporting natures of carbazole, TPECNz exhibits a strong deep red emission (lem = 648 nm) with a high fluorescence quantum yield of 96%, outstanding thermal property (Tg = 236 oC), and ambipolar charge-carrier-transporting property with a decent balance of mobility of electron (1.50 x 10-5 cm2 V-1 s-1) and hole (4.42 x 10-6 cm2 V-1 s-1). TPECNz is successfully employed as a non-doped emitter in OLED which displays deep red electroluminescent emission peaked at 659 nm with CIE coordinates of (0.664, 0.335)), an EQEmax of 3.32% and exciton utilization efficiency (EUE) of 47%.

No abstract

No abstract