D-A-D hexacatenar LCs containing bulky N-trialkoxylbenzyl carbazole caps with RGB emissions for full color palette and white LED applications

Abstract

Bulky N-trialkoxylbenzyl carbazoles were used as half disc donors capped at both terminals of a rigid calamitic cores containing biphenyl, bithiophene and bis-(cyano-2-thienylvinylene) phenyl respectively to construct three novel donor–acceptor-donor (D-A-D) hexacatenars DP, DT and TDCS. Their liquid crystalline and photophysical properties were studied. All three compounds can self-assemble into luminescence hexagonal columnar liquid crystals, emit blue, green and red fluorescence as typical three-primary-color luminescence. Through mixing DP, DT and TDCS in different ratios, high-intensity full-color luminescent solutions were achieved. By tuning the mixture of DP/DT/TDCS in a 5:8:10 wt ratio, white light solution with a color coordinate of (0.31, 0.33) was obtained. Furthermore, the film obtained by doping the mixture of DP/DT/TDCS (15:10:7) with poly ethylene glycol (PEG) (95%) could be utilized to fabricate a white LED.