Emission-Tunable and Elastically Bendable Organic Polymorphs for Lasing Media

Crystal engineering have served as a powerful strategy to grow organic molecular crystals with different physical behaviors and this strategy has been also attempted for a purpose to grow crystals with desired mechanical properties, however, it is quite challenging to endow all different crystal phases constructed by the same compound with unique reversible deformation, such as elastic bending. We herein report a rare example of all-polymorph elastic crystals accompanied with precisely tunable emission colors. Single crystal structure analyses, optical and mechanical properties have been fully investigated on all polymorphs. The color-tunable amplified spontaneous emissions of both the straight and elastically bent polymorphs demonstrate the applications of these elastic polymorphs in future wearable optoelectronic devices.