pqp

Here we report an efficient method for the synthesis of π-extended pyrrole-fused heteropine compounds and investigated their optical and electronic properties. A π-extended pyrrole-fused thiepine exhibited a “pitched π-stacking” structure in the crystal, and exhibited a high charge carrier mobility of up to 1.0 cm² V⁻¹ s⁻¹ in single-crystal field-effect transistors.

Abstract

Sulfur-embedded polycyclic aromatic compounds have been used as building blocks for numerous organic semiconductors over the past few decades. While the success is based on thiophene-containing compounds, aromatic compounds that contain thiepine, a sulfur-containing seven-membered-ring arene, has been less well investigated. Here we report the synthesis and properties of π-extended pyrrole-fused heteropine compounds such as thiepine and oxepine. A π-extended pyrrole-fused thiepine exhibited a “pitched π-stacking” structure in the crystal, and exhibited a high charge carrier mobility of up to 1.0 cm² V⁻¹ s⁻¹ in single-crystal field-effect transistors.

Spirocyclic hosts: Two types of dispirocyclic compounds were used to construct host materials for phosphorescent light‐emitting diodes. Variations in their molecular configuration have a profound effect on their physical, charge‐transport, and electroluminescent properties (see figure).

Abstract

Spirocyclic compounds such as 9,9′‐spirobifluorene (SBF) are becoming more and more attractive for use as host materials in organic optoelectronic devices. Herein, two dispirocycles, namely, dispiro[fluorene‐9,9′‐anthracene‐10′,9′′‐fluorene] and 10,10′′‐diphenyl‐10H,10′′H‐dispiro[acridine‐9,9′‐anthracene‐10′,9′′‐acridine], were used for the construction of host materials 1–4. The attached triphenylamino group determines the thermal, photophysical, electrochemical, and charge‐transport properties, and therefore they have different electroluminescent performances. The device based on dispiro[fluorene‐9,9′‐anthracene‐10′,9′′‐fluorene] (2) and 10,10′′‐diphenyl‐10H,10′′H‐dispiro[acridine‐9,9′‐anthracene‐10′,9′′‐acridine] (3) molecular platforms exhibited external quantum efficiencies of greater than 21 % with a very high power efficiency (≈100 lm W⁻¹). These results demonstrate the potential of extending the application of dispirocyclic molecular platforms with inherent rigidity for developing highly efficient host materials for organic light‐emitting diodes.

Abstract

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