2006 Volume 75 Issue 12 Pages 1471-1475
π-Conjugating oligomers in which a couple of thiophene and phenylene units are chained show structure-dependent visible fluorescence with a high quantum efficiency. Low-dimensional crystals self-assembled with these oligomers confine their fluorescence internally, resulting in novel light-emission phenomena. One of these phenomena is a lasing action based on stimulated resonance Raman scattering under the optical pumping of a crystal at the 0-0 absorption band. Another is pulse-shaped emission with a definite time delay under high-energy pumping at low temperatures. Both can be related to cooperative phenomena among the uniaxially oriented transition dipoles of the oligomer in the low-dimensional crystal.
