One-dimensional singlet energy migration in the columnar liquid crystal of a triphenylene derivative

The fluorescence properties of 2,3,6,7,10,11-hexa-n-hexyloxytriphenylene have been studied in solution and in its crystalline and columnar liquid-crystalline phases by steady-state and time-resolved spectroscopy. When an energy acceptor, perylene, is added to the organized phases, photosensitized fluorescence is observed. The triphenylene fluorescence decay curves obtained with the columnar phase are well described by a random walk of the excitation on a linear chain containing traps. The kinetic analysis permits the determination of the exciton hopping time (32 fs), the exciton diffusion coefficient (2.0 × 10–2 cm2 s–1) and the intrinsic trap molar fraction (10–3).