Highly Strained, Pseudoplastic, Cu-Pyridyl Coordination Polymer Crystal-Based Optical Waveguide Cavity

Crystals that are both mechanically flexible and fluorescent are highly sought-after materials for cutting-edge photonic devices. Herein, we report the first demonstration of acicular, pseudoplastic coordination polymer (CP) crystal waveguides. The crystals of the CP, namely, Cu2I2(dichloropyridine)2 (Cu-dcp), are highly flexible (pseudoplastic on coverslip) and emit bright green fluorescence. The single-crystal X-ray diffraction studies provide the consequences of molecular packing on the unique mechanical behavior. Mechanical micromanipulation using an atomic force microscope cantilever tip demonstrates the pseudoplasticity of the Cu-dcp crystal on the substrate. The optical waveguiding of the Cu-dcp microcrystals proves the real potential of mechanically flexible 1D CP crystal waveguides for photonic applications. Additionally, Cu-dcp’s pseudoplasticity enables the examination of how optical loss is affected by mechanical strain in optical waveguides with different bending angles. These studies enhance our knowledge of using inorganic CPs in photonic technologies and uncover numerous previously unexplored possibilities.