Improved crystal-growth and emission gain-narrowing of thiophene/phenylene co-oligomers

Large plate-like single crystals of several millimeters to similar to1 cm in size of organic semiconducting materials are prepared via an improved crystal-growth technique. The crystals (see Figure) exhibit self-waveguided amplified spontaneous emission with a relatively small threshold resulting from the excellent optical properties of the crystals, such as high transparency and low light scattering.