A Bifunctional Bulky Thienothiophene Derivative; Synthesis, Electronic‐Optical Properties and OLED Applications

Abstract

Applying thienothiophenes (TT) as a linker, a bulky bifunctional thienothiophene, TT-TPA-TPE3, possessing triphenylamine (TPA) and tetraphenylethylene (TPE) units, was designed, synthesized, and fully characterized. Its optical and electronic properties were explained by UV-Vis spectroscopy, cyclic voltammetry (CV) and Aggregation-Induced Emission (AIE) study. TT-TPA-TPE3 exhibited positive solvatochromism in the range of solvent polarities from DMF to toluene, displaying emissions from yellowish to bluish between 480-525 nm. Utilizing TT-TPA-TPE3 as a hole-transporting layer, its organic light emitting devices (OLEDs) were fabricated and their performances were investigated. The synthesized emitter exhibited green and blue emissions in device applications. A mega Stoke's shift of 114 nm in THF and a large Stoke's shift of 78 nm on ITO were observed. A maximum luminance of 580 cd m À 2 and a turn-on voltage of 7.01 V were obtained, indicating that TT-TPA-TPE3 has a good hole-transporting ability.

Triphenylamine/4,4′-Dimethoxytriphenylamine-Functionalized Thieno[3,2-b]thiophene Fluorophores with a High Quantum Efficiency: Synthesis and Photophysical Properties

“…The monoketones ( 1a–e ), TTs ( 2a–e ), some of the brominated TTs ( 3a, 3c, 3d ), and TT-TPA derivatives (4a, 4c, 4d) were synthesized following our previous reports. − The reaction of 3-bromothiophene with n- butyllithium at −78 °C was followed by the addition of elemental sulfur and then α haloketones to produce 1a–e in 84, 81, 79, 88, and 82% yields, respectively. Their ring closure reactions were conducted in the presence of polyphosphoric acid (PPA) in refluxing chlorobenzene to give 2a–e in 69, 85, 79, 94, and 83% yields, respectively.…”

“…An important advantage is that fluorescence properties can be finely tuned through chemical modification of their structures. − In particular, the geometrical design and conformation of the fluorophores have a crucial influence on their fluorescence and electroluminescence properties. − Thiophene-derived conjugated compounds, such as thienothiophenes (TTs), have particular importance as they are easy to modify in addition to their electron-rich, flat, and good electron delocalized structures. Thus, they are widely used in optoelectronic applications owing to their notable optic, electronic, and redox properties. − …”

Copolymers of 4‐thieno[3,2‐b]thiophen‐3‐ylbenzonitrile with anthracene and biphenyl; synthesis, characterization, electronic, optical, and thermal properties

“…Thus, this could be possible explanation for the higher band gap of the polymer P1 (2.01 eV) compare with the lower band gap of P2 (1.90 eV). Nerveless, both polymers had reasonably lower band gaps suitable for electronic applications 32–35 …”

“…Nerveless, both polymers had reasonably lower band gaps suitable for electronic applications. [32][33][34][35] Solvatochromism of P1 and P2 were investigated in five different solvents, having different polarities from polar to nonpolar; DMF, chloroform, THF, dichloromethane, and toluene, respectively (Luminogen concentration: 10 μM). Both polymers were found to be quite soluble in these solvents, which could be attributed to presence of the benzonitrile moieties.…”

Solution-processable donor–π–acceptor type thieno[3,2-b]thiophene derivatives; synthesis, photophysical properties and applications

“…Thieno [3,2-b]thiophenes (TT) have rigid, electron-rich and flat delocalized structures, making them promising p-bridges and donors to construct conjugated and low band gap organic semiconductors for organic light-emitting diodes (OLEDs), organic solar cells (OSCs), organic field-effect transistors (OFETs), lighting lasers and photosensitizers. [22][23][24][25][26][27][28][29][30][31][32][33] Another important building block is triphenylamine (TPA), having an ionization potential of 6.80 eV, lower than many organic/inorganic skeletons, which makes TPA a very strong electron-donating group for electronic materials. Moreover, TPA has a propeller-like shape with a torsion angle of 41.71 leading to a nonplanar structure with limiting intramolecular motion, which provides the resultant fluorescent molecule in solution with aggregation-induced emission (AIE) in the solid-state.…”