New Silicon‐Containing Polyquinolines: Synthesis, Characterization, and Electroluminescence

Abstract

Summary: This study reports the synthesis, characterization, and electroluminescent device application of three new silicon‐containing polyquinolines: poly(2,2′‐(bis(p‐phenyl)diphenylsilane)‐6,6′‐bis(4‐phenyl quinoline)), poly(2,2′‐(bis(p‐phenyl)octylmethylsilane)‐6,6′‐bis(4‐phenyl quinoline)), and poly(2,2′‐(bis(p‐phenyl)diphenylsilane)‐6,6′‐bis(4‐hexylquinoline)). The polymers with alkyl side chains were soluble in organic solvents. The new polymers showed robust thermal properties with glass transitions of 161–339 °C. Cyclic voltammetry of the polymers revealed quasi‐reversible reductions with onsets of −1.55 to −1.71 V (vs SCE) and corresponding electron affinities of 2.69–2.85 eV. Organic light‐emitting devices using new polyquinolines as emissive materials showed blue (CIE coordinates = 0.21, 0.20) or blue‐green (0.23, 0.36) electroluminescence with a moderate brightness (≈140 cd · m−2) and efficiency (0.04%). The results demonstrate that silicon‐containing polyquinolines are promising n‐type wide band‐gap semiconductors for organic electronics.Structures of new Si‐containing polyquinolines.magnified imageStructures of new Si‐containing polyquinolines.

An Aza-Diels–Alder Route to Polyquinolines

“…To date, polyquinolines have been prepared via a limited number of synthetic strategies, including Suzuki couplings, , the Sonogashira reaction, oxidative polymerizations, and the Friedländer synthesis. ,− The latter approach has proven particularly effective, as demonstrated in seminal studies by Jenekhe and co-workers. ,,− However, the known routes to polyquinolines suffer from some disadvantages; they frequently necessitate difficult multistep monomer syntheses, yield products with poor solubility, or provide access to only a limited number of structural motifs. For example, the Friedländer synthesis often requires the resulting polyquinolines to possess complex side chain substituents for enhanced solubility − and cannot provide access to certain backbone architectures, such as those containing 4,6-linked quinoline subunits. Thus, given the aforementioned limitations, there remains a need for the development of alternative routes to polyquinoline-type materials.…”

Photophysical and electrochemical characterization of new poly(arylene vinylene) copolymers containing quinoline or bisquinoline segments

“…Assuming the SCE energy level relative to vacuum −4.4 eV, the electron affinities (EA) of copolymers range from 2.66 eV for PBQFV to 3.53 eV for PQFVT . The EA of 2.66 eV of copolymer PBQFV is comparable to other polyquinolines,3(b), 39, 40 while the EA values of copolymers PQFV , PQFVT , and PBQPV are higher than that of polyquinolines. Quinoline‐containing copolymers PQFV and PQFVT displayed higher EA than bisquinoline‐containing PBQFV and PBQPV .…”

“…This is plausible for a polymer with ICT character due to the presence of electron‐donating (thiophene) and electron‐accepting (quinoline) segments. Nevertheless, the quantum yields of the other three copolymers are among the highest reported for polyquinolines3(b), 39, 40 or quinoline‐containing polymers 29, 30…”

Phosphine Oxide Containing Poly(pyridinium salt)s as Fire Retardant Materials

“…Over the past few years, nitrogen-containing polymers have received unabated attention in the design and synthesis of ionic polymers that have desirable electroluminescent (EL) [12,13,14,15,16,17,18,19,20,21,22,23,24,25], conducting [26], and liquid-crystalline (LC) properties [27,28,29,30,31,32,33,34,35,36,37,38,39,40,41], which make them attractive materials in many technological applications. Among the nitrogen-containing EL polymers, poly(pyridinium salt)s have received considerable interest and attention for applications in electronic and optoelectronic devices for displays and lighting, solar light harvesting, sensors, photonic devices, automobile and aircraft parts, and for packaging in the electronic industry.…”