In Situ Construction of One-Dimensional Component-Interchange Organic Core/Shell Microrods for Multicolor Continuous-Variable Optical Waveguide

The
core/shell micro-/nanostructures with versatility, tunability, stability,
dispersibility, and biocompatibility are widely applied in optics,
biomedicine, catalysis, and energy. Organic micro-/nanocrystals have
significant applications in miniaturized optoelectronics because of
their controllable self-assembly behavior, tunable optical properties,
and tailor-made molecular structure. Nevertheless, the advanced organic
core/shell micro-/nanostructures, which possess multifunctionality,
flexibility, and higher compatibility, are rarely demonstrated because
of the dynamic nature of molecular self-assembly and the complex epitaxial
relationship of material combination. Herein, we demonstrate the one-dimensional
organic core/shell micro-/nanostructures with component interchange,
which originates from the 4,4′-((1E,1′E)-(2,5-dimethoxy-1,4-phenylene)­bis­(ethene-2,1-diyl))­dipyridine
(DPEpe) single-crystal microrods or the DPEpe-HCl single-crystal microrods
after a reversible protonation or deprotonation process. Notably,
the DPEpe/DPEpe-HCl core/shell microrods display vivid visualizations
of tunable emission color via an efficient energy-transfer process
during the stepwise formation of a shell layer. More significantly,
these DPEpe/DPEpe-HCl and DPEpe-HCl/DPEpe core/shell microrods cooperatively
demonstrate the multicolor optical waveguide properties continuously
adjusted from green [CIE (0.326, 0.570)], to yellow [CIE (0.516, 0.465)],
and to red [CIE (0.614, 0.374)]. Our investigation provides a new
strategy to fabricate the organic core/shell micro-/nanostructures,
which can eventually contribute to the advanced organic optoelectronics
at the micro-/nanoscale.