Large Sheet‐Like Elastic Crystals for Flexible Organic Light‐Emitting Diode

Large sheet-like elastic crystals have vast potential applications in 2D flexible optoelectronic applications, such as information display and imaging, but this potential has been limited as the sheet-like crystal habit is not commonly observed in molecular crystals. Here, we report the crystal structure, mechanical elastic properties, mechanism of deformation, and 2D optoelectronic applications of 2,7-bis(4-methoxyphenyl)-9H-fluoro-9-one (BMeOPhFO). Elastically flexible crystals of 2D BMeOPhFO-R were obtained on a centimeter scale in both length and width. The elastic bending performance and mechanism were studied thoroughly in BMeOPhFO-R and its acicular polymorph BMeOPhFO-O, determined by micro-focused X-ray diffraction. Finally, a preliminary flexible organic light-emitting diode based on an elastic 2D single crystal of BMeOPhFO-R (bending curvature