Dual‐Mode Light Transduction through a Plastically Bendable Organic Crystal as an Optical Waveguide

Abstract

An anthracene derivative,9 ,10-dicyanoanthracene, crystallizes as fluorescent needle-like single crystals that can be readily plastically bent in two directions.S patially resolved photoluminescence analysis revealed that this material has robust optoelectronic properties that are preserved upon extreme crystal deformation. The highly flexible crystals were successfully tested as efficient switchable optical waveguiding elements for both active and passive light transduction, and the mode of operation depends on the wavelength of the incident light. This prototypical dual-mode organic optical crystalline fiber brings mechanically compliant molecular organic crystals closer to applications as novel light-transducing media for wireless transfer of information in all-organic micro-optoelectronic devices.Unlike conduction of electrons through metal conductors, transduction of light is inherently impervious to interference with external electromagnetic fields,a nd this calls for new organic materials as light-weight, cost-effective and secure optical transducers of information. Thef avorable optical properties and long-range order of molecular crystals is increasingly being recognized as an ew platform for construction of metal-free,a ll-organic electronics and soft robotics.P oor processing ability and less-than-optimal mechanical properties of the organic crystals,and particularly their pronounced brittleness and fragility,h owever,a re usually taken as major impediments against their implementation in flexible devices,inwhich thin organic films have long been superior and the preferred phase of choice.T he recent advent of methodologies for controlled crystal growth has provided strategies for fairly good control over the habit, the aspect ratio,a nd mosaic spread of molecular crystals. [1] Moreover,t he burgeoning research into mechanical properties of molecular crystals has revealed that certain organic crystals can be extraordinarily mechanically compliant;t hey are endowed with atypical properties,s uch as elasticity and plasticity that are comparable to those of metallic conduc-

Optical Waveguiding Organic Single Crystals Exhibiting Physical and Chemical Bending Features

“…The study of the mechanical properties of organic crystals has become a burgeoning area in crystal engineering owing to potential applications in various fields . Recently, research on elastic organic single crystals (EOSCs) has become a cutting‐edge field because EOSCs can be applied in flexible devices, which is a focus in the development of current advanced materials and technologies . Ghosh and Reddy are pioneers in the study of EOSCs and proposed mature mechanisms .…”

Is a Bent Crystal Still a Single Crystal?

“…[36][37][38][39][40][41] It is important to note that even though evolution of dislocations was not reported to occur it does not mean it did not occur. [36][37][38][39][40][41] It is important to note that even though evolution of dislocations was not reported to occur it does not mean it did not occur.…”

Ist ein gebogener Kristall immer noch ein Einkristall?

“…[36][37][38][39][40][41] Allerdings:A uch wenn nicht immer von Delaminierung berichtet wurde,b edeutet dies nicht automatisch auch, dass sie nicht stattgefunden haben muss.D er Effekt wurde mçglicherweise schlicht und einfach übersehen, oder die Proben wurden nicht an Instrumenten mit ausreichender Auflçsung charakterisiert, um eine gegebenenfalls vorhandene Delaminierung zu erfassen. [36][37][38][39][40][41] Allerdings:A uch wenn nicht immer von Delaminierung berichtet wurde,b edeutet dies nicht automatisch auch, dass sie nicht stattgefunden haben muss.D er Effekt wurde mçglicherweise schlicht und einfach übersehen, oder die Proben wurden nicht an Instrumenten mit ausreichender Auflçsung charakterisiert, um eine gegebenenfalls vorhandene Delaminierung zu erfassen.…”