Cyano-Substituted Oligo(p-phenylene vinylene) Single Crystals: A Promising Laser Material

Organic crystals that combine high charge-carrier mobility and excellent light-emission characteristics are expected to be of interest for light-emitting transistors and diodes, and may offer renewed hope for electrically pumped laser action. High-luminescence-efficiency cyano-substituted oligo(p phenylene vinylene) (CN-DPDSB) crystals (eta approximate to 95%) grown by the physical vapor transport method is reported here, with high mobilities (at approximate to 10(-2) cm(2) V-1 s(-1) order of magnitude) as measured by time-of-flight. The CN-DPDSB crystals have well-balanced bipolar carrier-transport characteristics (mu(hole) approximate to 2.5-5.5 x 10(-2) cm(2) V-1 s(-1); mu(electron) approximate to 0.9-1.3 x 10(-2) cm(2) V-1 s(-1)) and excellent optically pumped laser properties. The threshold for amplified spontaneous emission (ASE) is about 4.6 mu J per pulse (23 KW cm(-2)), while the gain coefficient at the peak wavelength of ASE and the loss coefficient caused by scattering are approximate to 35 and approximate to 1.7 cm(-1), respectively. This indicates that CN-DPDSB crystals are promising candidates for organic laser diodes.