Triphenylamine/Tetraphenylethylene Substituted 4-Thieno[3,2-<i>b</i>]thiophen-3-ylbenzonitriles: Synthesis, Photophysical-Electronic Properties, and Applications

Five novel fluorescent materials, TT-TPA, TT-TPE, TPA-TT-TPA, TPE-TT-TPE, and TPA-TT-TPE, containing a strongly electron-donating triphenylamine (TPA) bulky tetraphenylethylene (TPE), linked through thienothiophene, 4-thieno[3,2-b]thiophen-3-ylbenzonitrile, possessing electron-withdrawing nitrile moiety, were systematically designed, synthesized, their optical electrochemical properties compared. The structure of the main skeleton, 4-thieno[3,2-b]thiophen-3-ylbenzonitrile (TT-CN), along with its precursor, monoketone 4-(2-bromoacetyl)benzonitrile, clarified by single-crystal X-ray diffraction. Information on conformation electronic was obtained density functional theory (DFT), which revealed that they are suitable compounds for OLED applications. They exhibited mega Stokes shifts between 113 177 nm, except TT-TPE TT-CN, showed positive solvatochromic behavior from blue to orange increasing solvent polarity dual emission both at solid-state in solution. Their quantum yields recorded be 9 58%, solution determined close 100%. As had yields, OLEDs fabricated, performances maximum luminance around 2800 cd m–2, current efficiency 4.70 A–1 displayed colors green yellowish green.