Cyano‐Substituted Oligo(<i>p</i>‐phenylene vinylene) Single Crystals: A Promising Laser Material

Abstract

Abstract 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 ( η ≈ 95%) grown by the physical vapor transport method is reported here, with high mobilities (at ≈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 ( μ hole ≈ 2.5–5.5 × 10 −2 cm 2 V −1 s −1 ; μ electron ≈ 0.9–1.3 × 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 μJ per pulse (23 KW cm −2 ), while the gain coefficient at the peak wavelength of ASE and the loss coefficient caused by scattering are ≈35 and ≈1.7 cm −1 , respectively. This indicates that CN‐DPDSB crystals are promising candidates for organic laser diodes.