Starburst molecules based on π-electron systems as materials for organic electroluminescent devices

A Novel Family of Boron‐Containing Hole‐Blocking Amorphous Molecular Materials for Blue‐ and Blue–Violet‐Emitting Organic Electroluminescent Devices

“…The HOMO± LUMO energy gaps of TPhB, TBPhB, TTPhB, and TTPhPhB were estimated to be approximately 3.5 eV from the energy thresholds of their electronic absorption spectra. Based on the reduction potential (±2.01 V vs. Ag/Ag + ) and the LUMO energy level (3.1 eV) of Alq 3 , [13] the LUMO energy levels of TPhB, TBPhB, TTPhB, and TTPhPhB were estimated to be ca. 2.6 eV from the values of their half-wave reduction potentials.…”

“…[8,16,17] They have been used as good hole transporters in Alq 3 -based green-emitting organic EL devices. [2,9,13,18] As described in the introduction, the use of these materials as blue-or blue±violet emitters instead of hole transporters in organic EL devices requires the presence of either an electron transporter with an effective hole-blocking ability, or a hole blocker inserted in between the emitting layer and the electron-transport layer. A device using TPD as an emitter and 3-(biphenyl-4-yl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ) as an electron transporter has been reported; however, the emission from TPD is accompanied by another stronger emission, peaking at 460 nm, [16] which may be attributable to the emission from an exciplex formed between TPD and TAZ.…”

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

“…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).…”

The Effect of Annealing of Organic Thin Films on Charge Injection in Organic Electroluminescent Devices.

“…We have previously shown that multilayer organic EL devices consisting of the emitting layer of Alga and double hole-transport layers of m-MTDATA as HTL 1 and TPD or other holetransporting materials as HTL2 (Figure 1), exhibits higher luminous efficiency and significantly enhanced operational durability than the corresponding double layer device in the absence of m-MTDATA [3,12]. In the present study, materials with higher glass-transition temperatures (Tgs), [13] are used as HTL 1 and HTL 2, respectively, in order to investigate annealing effect on charge injection in organic EL devices.…”