Synthesis, aggregation-induced emission and electroluminescence properties of three new phenylethylene derivatives comprising carbazole and (dimesitylboranyl)phenyl groups

Abstract

It is essential that light-emitting materials possess high fluorescence intensity in the solid-state and a stable charge-transporting ability for the construction of organic light-emitting diodes (OLEDs) with outstanding performance. In this paper, three phenylethene derivatives, 3-(4-(dimesitylboryl)phenyl)-6-(1,2,2-triphenylvinyl)-9-ethyl-9H-carbazole (DBPTECZ), 3-(4-(dimesitylboryl)phenyl)-6-(1,2-diphenylvinyl)-9-ethyl-9H-carbazole (DBPDPECZ) and 3-(1-(4′-(dimesitylboryl)-[1,1′-biphenyl]-4-yl)-2-phenylvinyl)-9-ethyl-9H-carbazole (DBBPPECZ) with a hole-transporting group (carbazole) and an electron-transporting group ((dimesitylboranyl)phenyl group), are synthesized and sufficiently characterized using elemental analysis, and ¹H NMR, ¹³C NMR and mass spectrometry. All three compounds show typical AIE features with strong solid-state fluorescence. Besides, they also possess good thermal stabilities with T_d of 219 °C, 188 °C and 167 °C respectively. Furthermore, non-doped OLED devices employing DBPTECZ, DBPDPECZ, and DBBPPECZ as functional layers are fabricated, showing remarkable performance with blue-green, deep blue and sky blue emissions, respectively. The L_max values of the three molecules reach up to 21 054 cd m⁻², 4376 cd m⁻² and 12 080 cd m⁻², and η_C,max are 3.34 cd A⁻¹, 2.34 cd A⁻¹ and 1.73 cd A⁻¹, respectively. These results demonstrate that the present compounds are promising candidates for OLEDs.