A Facile Approach to Highly Efficient and Thermally Stable Solid‐State Emitters: Knitting up AIE‐Active TPE Luminogens by Aryl Linkers

Abstract A facile approach to thermally stable and efficient solid‐state emitters is proposed. By hooking up tetraphenylethene (TPE) units through aryl linkers under Suzuki coupling conditions, a series of arylene bis(tetraphenylethene)s (TPE‐Ar‐TPE Ar=2,5‐dimethyl‐1,4‐phenylene, 2,5‐bis(hexyloxyl)‐1,4‐phenylene, 1,5‐naphthylene, and 9,10‐anthracenylene) are prepared in satisfactory to high yields (67–96 %). These molecules are nonluminescent when dissolved in solutions but become highly emissive when aggregated in poor solvents or fabricated as thin film in the solid state, displaying a phenomenon of aggregation‐induced emission. Fluorescence quantum yields of 100 % were achieved in the amorphous films of the luminogens. The luminogens exhibit mechano‐, vapo‐, and thermochromism: their emissions can be repeatedly switched between blue and blue‐green colors by simple grinding‐fuming and grinding‐heating cycles owing to the morphological change from a crystalline to an amorphous state and vice versa. These compounds are thermally stable, losing little of their weight at high temperatures of 421–452 °C. All the luminogens are morphological stable with high glass transition temperatures. Multilayer light‐emitting diodes with a device configuration of ITO/NPB/dye/TPBi/Alq 3 /LiF/Al are fabricated, which emit sky‐blue electroluminescence with maximum luminance and external quantum efficiency of 7900 cd m −2 and 2.1 %, respectively.