Multi-faceted bending and multi-directional flexible optical waveguide of the elastic organic single crystal

Abstract

Multi-faceted bending elastic organic single crystals are extremely rare and have potential applications in optical communication, mechanically tunable flexible fluorochromic materials, etc., which have attracted great attention of researchers. Herein, we reported two compounds with simple structures, namely 1,3-dimethylbarbituric acid (DMBA) and its derivative (TPABA). Under stress, both (200) and (002) faces of TPABA crystal could undergo reversible elastic deformation, possessing rare multi-faceted bending properties. The abundant weak isotropic intermolecular interactions (such as H-bonding, etc.) in crystal could buffer mechanical stress and prevent crystal fracture. Fortunately, TPABA crystals showed multi-directional flexible optical waveguide characteristics. The corresponding optical loss coefficients were 0.57 dBmm−1 (582 nm, straight line), 0.75 dBmm−1 (583 nm, (002) face bending), and 0.58 dBmm−1 (587 nm, (200) face bending). Unlike TPABA crystals, under stress, the (040) and (200) faces of the DMBA crystal underwent plastic deformation and fracture, respectively, showing the characteristics of single-faceted plastic deformation.