Highly Elastic Organic Crystals for Flexible Optical Waveguides

Abstract

The study of elastic organic single crystals (EOSCs) has emerged as a cutting-edge research of crystal engineering. Although a few EOSCs have been reported recently, those suitable for optical/optoelectronic applications have not been realized. Here, we report an elastic crystal of a Schiff base, (E)-1-(4-(dimethylamino)phenyl)iminomethyl-2-hydroxyl-naphthalene. The crystal is highly bendable under external stress and able to regain immediately its original straight shape when the stress is released. It displays bright orange-red emission with a high fluorescence quantum yield of 0.43. Intriguingly, it can serve as a low-loss optical waveguide even at the highly bent state. Our result highlights the feature and utility of "elasticity" of organic crystals.

Organic Functional Molecule‐Based Single‐Crystalline Nanowires for Optical Waveguides and Their Patterned Crystals

“…It could be seen that the nanowire arrays showed a series of diffraction peaks with 2θ degrees of 6.039°, 11.518°, 17.221°, and 23.105°, which was appointed as (001), (002), (003), (004) planes, respectively. The result was consistent with the previously reported o ‐BCB crystal ( a = 3.9127 Å, b = 6.9657 Å, c = 15.611 Å, α = 95.798, β = 93.445, and γ = 92.199, space group of P‐1 ) …”

An Organic Crystal with High Elasticity at an Ultra‐Low Temperature (77 K) and Shapeability at High Temperatures

“…In line with our studies on EOSCs and their applications, we have developed a new EOSC based on a π‐conjugated molecule, ( Z )‐2‐(4‐((( E )‐2‐hydroxy‐5‐methylbenzylidene)amino)phenyl)‐3‐phenylacrylonitrile (HMBPPA) (Figure a). The crystal was found to show elasticity not only at room temperature but also even in liquid nitrogen (LN 2 ).…”

Is a Bent Crystal Still a Single Crystal?

“…[25][26][27][28][29][30] Single-crystal X-ray diffraction analyses were performed on elastic cocrystals of caffeine and 4-chloro-3-nitrobenzoic acid to evaluate the structural integrity and crystallinity in the bent region. [25][26][27][28][29][30] Single-crystal X-ray diffraction analyses were performed on elastic cocrystals of caffeine and 4-chloro-3-nitrobenzoic acid to evaluate the structural integrity and crystallinity in the bent region.…”