1D versus 2D cocrystals growth via microspacing in-air sublimation

Abstract

Organic cocrystals possess valuable properties owing to the synergistic effect of the individual components. However, the growth of molecular cocrystals is still in its primary stage. Here we develop a microspacing in-air sublimation method to grow organic cocrystals, and furthermore to realize morphology control on them, which is essential for structure–property relations. A series of polycyclic aromatic hydrocarbon (PAH)‒1,2,4,5-tetracyanobenzene (TCNB) complexes cocrystals are grown directly on the substrate, with the morphology tunable from 1D needle-like to 2D plate-like on demand. Spatially resolved photoluminescence spectra analyses on different cocrystals display morphology dependent and anisotropic optical waveguiding properties. In situ observation and energy calculations of the crystallization processes reveal the formation mechanism being from a competition between growth kinetics-defined crystal habit and the thermodynamics driving force. This growth technique may serve the future demand for tunable morphology organic cocrystals in different functional applications.

Two-photon excited deep-red and near-infrared emissive organic co-crystals

“…The powder XRD pattern of CNC-T, grown on a glass substrate, displays ( Supplementary Fig. 18c) strong (001) and (002) diffraction peaks, indicating 35 that the triangular growth face of the co-crystal is parallel to the (00l) lattice plane. This experimental data is confirmed by the simulated morphology of the co-crystals.…”

“…Inspired by these advances, extensive investigations of organic co-crystals have been pursued by scientists in different areas of materials science 32 , 33 . To date, abundant properties, such as ambipolar charge transport 34 , optical waveguide modulation 35 , piezochromic behavior 36 , 37 , thermal-mechanical response 38 , photothermal conversion 39 , and room-temperature phosphorescence 40 , have been achieved by simple co-crystallization. The engineering of NIR emissive co-crystals that exhibit TPA, however, remains as a challenge.…”

Recent Progress in Polycyclic Aromatic Hydrocarbon‐Based Organic Co‐Crystals

“…By using this method, Tao team prepared a series of PAH‐based co‐crystals and hydrogen‐bonded pharmaceutical co‐crystals with diverse morphologies ( i.e . needle‐like and plate‐like) [33] …”

Multifunctional Features of Organic Charge‐Transfer Complexes: Advances and Perspectives

“…Very recently, to address the high‐cost vacuum system and time consuming issue, a microspacing in‐air sublimation (MAS) method was developed to directly grow organic co‐crystals (a series of polycyclic aromatic hydrocarbon (PAH)–acceptor complexes and hydrogen‐bonded pharmaceutical co‐crystals) on the substrate [48] . These binary co‐crystals could exhibit 1D needle‐like morphology or 2D plate‐like shape, depending on the temperature and the way to mix the starting materials together (Figure 6).…”

“…These binary co‐crystals could exhibit 1D needle‐like morphology or 2D plate‐like shape, depending on the temperature and the way to mix the starting materials together (Figure 6). [48] …”