New Carbazole‐Based Hyperbranched Conjugated Polymer with Good Hole‐Transporting Properties

Abstract

A copper‐catalyzed Ullmann C–N coupling reaction was used for the preparation of a new carbazole‐based HPU in good yield with a high molecular weight through a facile “AB2 + A2 + B2”‐type approach. The HPU exhibited good solubility, high thermal stability with a Tg of 196 °C, as well as a suitable HOMO level for good hole injection and transporting properties. A two‐layer OLED device, using HPU as hole‐transporting layer (HTL) and Alq3 as the light‐emitting layer, was fabricated to investigate the hole‐transporting properties of HPU. The luminance efficiency reached 1.14 cd · A−1 at the maximum current density of 1 240 mA · cm−2, while the maximum luminance efficiency was 1.65 cd · A−1, indicating the high morphological and thermal stability of HPU.magnified image

Cross-linkable fluorenyl-substituted aromatic amines for polymeric hole transporting networks

“…2-Bromo-9,9-di(3-methyloxetan-3-ylmethyl)fluorene (2) as a key material was synthesized from commercially available 2-bromofluorene and 3-bromomethyl-3-methyloxetane in a two phase system by similar procedure as it is described in the literature [16,17]. An excess of the bromo compound 2 was reacted with aniline or N,N 0 -diphenylbenzidine by the method of Buchwald-Hartwig [18] to afford N,N 0 -di [9,9-di(3-methyloxetan-3-ylmethyl)fluorenyl]-Nphenylamine (3) or N,N 0 -di[9,9-di(3-methyloxetan-3-ylmethyl)fluoren-9-yl]-N,N 0 -diphenylbenzidine (4), respectively.…”

“…Efficient OLEDs can be obtained only by building multilayer structures [2][3][4]. The main difficulty in the preparation of such devices by spincoating is the solubility of the material which forms the bottom layer onto which the top layer has to be cast, because most organic semiconductors are soluble in the same solvents.…”

Contemporary Approaches for Conventional and Light‐Mediated Synthesis of Conjugated Heteroaromatic Polymers

“…Li and collaborators successfully synthesized carbazole-based conjugated polymers that exhibited high solubility and thermal stability as hole-transport material using one-pot Ullmann coupling polymerization (Scheme 5). [73] Recently, Hu and co-workers synthesized Pd-nanoreactors by the deposition of PdCl 2 solution into carbon nanomembranes as catalysts for the controlled step-growth polymerization of a Scheme 4. Synthesis of 2D polythiophene derivatives using AgNPs.…”

Topological Arrangement of Fluorenyl-Substituted Carbazole Triads and Starbursts: Synthesis and Optoelectronic Properties

“…At the same time, the topological features, the way that functional units are connected and the three-dimensional structures that materials are constructed of, also play an important role and should be carefully examined. For example, from linear polymer chains to hyperbranched polymer chain structures, or from oligomers to dendrimers and starbursts, the physical properties of the materials change greatly. The knowledge of how the topology affects the materials’ properties, such as frontier energy levels, low lying triplet energies, optical properties, and transport properties, is an important topic and deserves more attention.…”