Engineering Mechanical Compliance of an Organic Compound toward Flexible Crystal Lasing Media

Recently, organic
crystals with mechanical flexibility have been
emerging as a hot research topic due to their great potentials in
flexible optoelectronics. However, organic crystals exhibiting elastic
bending or plastic bending are relatively rare. In this study, we
proposed a strategy to improve the probability of crystal flexibility
as well as to regulate the mechanical properties by controlling polymorphism.
Three different emissive organic polymorphs Cry-G, Cry-Y, and Cry-O with elastic, plastic, and brittle
natures, respectively, were obtained by fine-tuning crystallization
conditions of a diaryl β-diketone compound. Cry-G was found to transduce light and amplify the self-waveguided emission
efficiently along the crystal body in the elastically bent state,
demonstrating its multifunctional applications in flexible optical
devices. This study is of great scientific significance not only to
engineer mechanical compliance of organic crystals but also to highlight
the utility of “crystal flexibility”.