One‐dimensional molecular co‐crystal alloys capable of full‐color emission for low‐loss optical waveguide and optical logic gate

Abstract

The luminescence color of molecule‐based photoactive materials is the key to the applications in lighting and optical communication. Realizing continuous regulation of emission color in molecular systems is highly desirable but still remains a challenge due to the individual emission band of purely organic molecules. Herein, a novel alloy strategy based on molecular co‐crystals is reported. By adjusting the molar ratio of pyrene (Py) and fluorathene (Flu), three types of molecular co‐crystal alloys (MCAs) assemblies are prepared involving Py‐Flu‐OFN‐x%, Py‐Flu‐TFP‐x%, Py‐Flu‐TCNB‐x%. Multiple energy level structure and Förster resonance energy transfer (FRET) process endow materials with tunable full‐spectra emission color in visible region. Impressively, these MCAs and co‐crystals can be successfully applied to low optical loss waveguide and optical logic gate by virtue of all‐color luminescence from blue across green to red, together with smooth surface of one‐dimensional microrods, which show promising applications as continuous light emitters for advance photonics applications.

Precise Synthesis of Organic Cocrystal Alloys with Full‐Spectrum Emission Characteristics for the Stepless Color Changing Display

“…When two cocrystal components are assembled into an organic CT alloy, the π–π interaction and van der Waals forces between molecules are considered non‐covalent interaction forces. [ 52 ] The organic CT alloy prepared by us is composed of two groups of organic CT cocrystals with similar molecular size and similar binding force (binding with the same receptor). The organic alloys display tailored luminescence properties based on the CT competitive relationship between the two different luminescent color cocrystals.…”

“…Which can continuously adjust the luminous color, achieve stepless color‐changing, and further adjust the fluorescence quantum yield and fluorescence lifetime of the crystal, combining the double point of organic CT cocrystal and organic alloy. [ 51,52 ] Cocrystals with weakly combining capacity but high energy emissions can be used as donors (Such as o ‐TCP‐TP). The ones with more vital combining capacity and low energy emission can be considered acceptors (Such as p ‐TCP‐Pe).…”

“…And their fluorescence lifetimes are 10.93 ns, 6.24 ns, and 7.11 ns, respectively (Figure S18c, Supporting Information). [ 52 ] As shown in Figure S10 (Supporting Information), the XRD patterns reveal that the p ‐TCP‐Cor 0.9 ‐Pe 0.1 alloys are almost isomorphic to p ‐TCP‐Pe, p ‐TCP‐Cor cocrystals, and they all have regular rod‐like structures, and Energy Dispersive Spectroscopy (EDS) spectra shows that the elements of these three groups of crystals are evenly distributed within the rod‐like structure (Figure S20, Supporting Information). The FL spectra of these organic CT alloys with different doping ratios have been characterized to investigate the optical properties (Figure 6b,e).…”

“…For cocrystal alloy, by varying the type/proportion of organic molecules, the luminous color of the crystal can be adjusted. [ 51,52 ] Therefore, a productive combination of cocrystals and alloys could supply a unique means for designing photoelectronic materials, named organic cocrystal alloys.…”

Shape-Dependent Optical Waveguides and Low-Threshold Lasers from Polymorphic Two-Dimensional Organic Single Crystals

“…Precision manipulation of photon behavior, including transmission, − polarization, − and amplification, , within microstructures constitutes a foundational pursuit in the development of integrated photonic devices for applications spanning information transmission, storage, and encryption. , Among potential materials for optoelectronic devices, two-dimensional (2D) organic single crystals (OSCs) stand out due to their notably low defect density and exceptional photoelectric properties and have gained extensive utilization in the exploration of high-performance devices such as organic light-emitting transistors (OLETs) − and organic light-emitting diodes (OLEDs). , In the realm of 2D-OSCs, the molecular interactions orchestrate a highly ordered molecular arrangement, culminating in a regular morphology and prominently oriented molecular transition dipole moments (TDMs). − The interaction between light and matter induces reabsorption effects, wherein the intensity correlates directly with the dot product of polarization and TDM orientation (μ), thereby instigating energy loss during propagation. Notably, the initial polarization of the emitted photons aligns with μ. Consequently, given the directional confinement within the 2D plane, modulation of TDM orientation emerges as an effective avenue to govern photon behavior.…”