Blue Emitters For Organic Light-emitting Diodes Research Articles

Highly Efficient Blue Organic Light Emitting Diodes Based on Cyclohexane-Fused Quinoxaline Acceptor.

Exploring blue organic light emitting diodes (OLED) is an important but challenging issue. Herein, to achieve blue-shifted emission, cyclohexane is fused to quinoxaline to weaken the electron-withdrawing ability and conjugation degree of the acceptor. As a result, blue to cyan fluorescent emitters of Me-DPA-TTPZ, tBu-DPA-TTPZ, and TPA-TTPZ were designed and synthesized with donors of diphenylamine and triphenylamine, which exhibit high photoluminescence quantum yields and good thermal stability. In OLEDs with emitters of TPA-TTPZ, the sensitized and nonsensitized devices demonstrate deep-blue (449 nm) and blue (468 nm) emission with maximum external quantum efficiency and CIE coordinates of 6.1%, (0.15, 0.10) and 5.1%, (0.17, 0.22), respectively, validating their potential as blue emitters in OLEDs.

Two Novel Tetrahedrally Silicon-Based Benzimidazole Derivatives: Potentials as Blue Emitters for OLEDs

Two novel silicon-centered benzimidazole derivatives, Bis(4-(benzimidazol-1-yl)phenyl) dimethylsilane (1) and Bis(3-(benzimidazol-1-yl)phenyl)dimethylsilane (2) have been synthesized and determined by IR, 1H NMR, 13C NMR and mass spectroscopy. These compounds have high thermal stability and are fluorescent with emission in the region of violet to blue, which could be potentially applied as blue emitters in organic light-emitting diodes (OLEDs) display.

Synthesis and characterization of novel 2,5-diphenyl-1,3,4-oxadiazole derivatives of anthracene and its application as electron transporting blue emitters in OLEDs

With a general aim to make anthracene derivatives multifunctional (n-type emitter) and also study their suitability as electron transport layers for organic light emitting diodes (OLED), we report the synthesis and characterization of five novel molecules in which the 9 and 10 positions of anthracene have been directly substituted by 2,5-diphenyl-1,3,4-oxadiazole groups. We have carried out detailed characterization of these molecules which include photophysical, electrochemical, thermal, electroluminescent and computational studies. The electron affinity is very high, around 3.7 eV, and the ionization potential is around 6.7–6.8 eV, which is relatively higher than the most commonly used electron transport electroluminescent layer Alq 3. The studies reveal that the new molecules being reported by us, in addition to the high thermal stability, are quite efficient in a two layer unoptimized nondoped device with the device structure ITO/α-NPD/ 10a– 11b/LiF/Al and have an emission in pure blue. They also show very high efficiency as electron transport layer in device structure ITO(120 nm)/α-NPD(30 nm)/Ir(ppy) 3 doped CBP(35 nm)/BCP(6 nm)/ 10a(28 nm)/LiF(1 nm)/Al(150 nm). From these studies we conclude that these anthracene derivatives also have considerable potential as multifunctional layers and as electron transport layers in OLED.