Controlling Morphological Dimensions of Organic Charge‐Transfer Cocrystal by Manipulating the Growth Kinetics for Optical Waveguide Applications

• Published in: Advanced optical materials 2023-06, Vol.11 (12), p.n/a
• Main Authors: Wu, Bin, Zhuo, Ming‐Peng, Chen, Song, Su, Yang, Yu, You‐Jun, Fan, Jian‐Zhong, Wang, Zuo‐Shan, Wang, Xue‐Dong
• Format: Article
• Language: English
• Subjects: Charge transfer; Crystal structure; Materials science; Microcrystals; Morphology; noncovalent interactions; Optical waveguides; Optics; Optoelectronic devices; organic cocrystals; Self-assembly; Tetracyanoquinodimethane; thermodynamic/kinetic growth pathway
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202202895

Precise fabrication of organic micro/nanostructures with regular morphology has gained a considerable concern in developing high‐performance optoelectronic devices, which is still a huge challenge to realize tunable morphology without the dependence on molecule packing arrangement. Herein, a thermodynamic/kinetic controlled self‐assembly for triphenylene‐7,7,8,8‐tetracyanoquinodimethane (TP‐TCNQ) cocrystal, with well‐defined microwires and microplates based on the same crystal structure, is proposed. With the low solution concentration of C = 5 mm, the comparable growth rates along [011] driven by π–π interaction and along [100] driven by charge‐transfer (CT) interaction facilitate the formation of thermodynamically favored shape of microplates. In contrast, the prominent CT interaction along [100] leads to the construction of microwires at kinetic state under high‐concentration solution of C = 10 mm. Furthermore, the prepared TP‐TCNQ microwires and microplates demonstrate isotropic photonic transmissions with the low optical loss coefficient of 0.033 and 0.042 dB µm−1, respectively. This strategy provides a novel avenue to finely construct the organic microcrystals with desired morphology for potential optoelectronics. Through regulating the thermodynamic/kinetic growth pathways, a controlled self‐assembly strategy for precise synthesis of organic cocrystals with desired morphologies is demonstrated. The comparable π–π interaction along [011] and charge‐transfer (CT) interaction along [100] facilitate the formation of microplates under low solution concentration, while strong CT interaction along [100] leads to the fabrication of microwires under high concentration.