Flexible organic crystal with dual mechanical bending capabilities and optical waveguiding directionality

The study of organic luminescent crystal material has become a hot topic in the field of flexible optoelectronics. In this context, we report a crystal of 2,5-dihydro-3,6-bis (pentanamine) dimethyl terephthalate, which exhibits the unique property of self-doping, coupled with dual mechanical bending capabilities. Notably, the crystal exhibits optical waveguide properties, which highlights its potential application in flexible optoelectronics. In this work, through a simple "self-doping” process and controlled morphology, we obtained the synthesis of high-quality bulk organic crystals of varied sizes that not only bend elastically but also bend plastically as the molecular layer undergoes slippage. Subsequent, analysis of the crystal structure was conducted to investigate the reason for its dual mechanical bending capabilities. Our findings suggested that the optical waveguide is not only available in linear shape, elastic bending shape, and plastic bending shape, but also in large-size flake crystals. More importantly, the propagation of light in this crystal is directional owing to the anisotropy of the crystals. It is also proven that organic crystals have the potential to be applied in advanced optoelectronic devices, offering the possibility of their application as directional waveguide materials. [Display omitted] •Dual mechanical bending capabilities through a simple "self doping” process.•Displays two-dimensional optical waveguide directivity.•High fluorescence quantum efficiency and low optical loss coefficient of 0.149 dB*mm−1.