Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

Abstract

In this work, we designed and synthesized four bipolar blue-emitting materials with carbazole, imidazole, and biphenyl as donor, acceptor, and p bridge, respectively. The twisted phenylimidazole acceptor leads to a wider band-gap and hence deeper blue emission than the conjugated phenanthrimidazole acceptor. For the substituents on the carbazole donor, the t-butyl group could prevent the intramolecular charge transfer (ICT) process more effectively than the methoxy group. A non-doped deep-blue organic light-emitting diodes (OLED) is obtained with CIE coordinates of (0.159, 0.080), a maximum luminance of 11,364 cd/m2, and a maximum EQE of 4.43%.

The Role of Intermolecular Interaction on Aggregation-Induced Emission Phenomenon and OLED Performance

“…As expected, both HOMO and LUMO levels are similar for all molecules (see Table 1 ). As expected, the HOMO orbital is located mainly on the carbazole part [ 37 ]. On the other hand, the LUMO orbital is more dominated by the contribution from 2-cyanoacrylic ester moiety.…”

Donor Influence on the Optoelectronic Properties of N‐Substituted Tetraphenylimidazole Derivatives

“…Various starting precursors can be used in a multicomponent condensation reaction to obtain differently substituted imidazole derivatives with structural diversity easily installed at the N1, C2, and C4/5 ring positions. Typical synthesis routes for imidazole‐containing emitter materials introduce electron donor, or π‐spacer and donor groups at C2 [23–30] . These groups tend to be conjugated with the imidazole, as arenes such as phenylene rings adopt a relatively co‐planar conformation.…”

“…Typical synthesis routes for imidazole-containing emitter materials introduce electron donor, or π-spacer and donor groups at C2. [23][24][25][26][27][28][29][30] These groups tend to be conjugated with the imidazole, as arenes such as phenylene rings adopt a relatively co-planar conformation. By contrast, phenylene substituents at C5 or N1 adopt a significantly more twisted conformation.…”

Photoluminescent polymer micelles with thermo-/pH-/metal responsibility and their features in selective optical sensing of Pd(ii) cations

“…In the issue of π-conjugated polymers, the imidazole-conjugated structure is also very effective for developing photoluminescent materials. 41 Imidazole is a heterocyclic compound with an imine group as a proton acceptor and an amine group as a proton donor in the same aromatic ring, and imidazole itself is also sensitive to pH and/or metal ions. The architecture of π-conjugated polymers containing imidazole rings or imidazole-condensed rings has attracted much attention because of their photonic properties as charge transfer chromophores and the unique photophysical process of excited-state intramolecular proton transfer (ESIPT).…”