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

摘要

Precise fabrication of organic micro/nanostructures with regular morphologyhas gained a considerable concern in developing high-performance optoelectronicdevices, which is still a huge challenge to realize tunable morphologywithout 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 microwiresand microplates based on the same crystal structure, is proposed. Withthe low solution concentration of C = 5 mm, the comparable growth ratesalong 011 driven by π–π interaction and along 100 driven by charge-transfer(CT) interaction facilitate the formation of thermodynamically favored shapeof microplates. In contrast, the prominent CT interaction along 100 leadsto the construction of microwires at kinetic state under high-concentrationsolution of C = 10 mm. Furthermore, the prepared TP-TCNQ microwiresand microplates demonstrate isotropic photonic transmissions with the lowoptical loss coefficient of 0.033 and 0.042 dB μm~（?1）, respectively. This strategyprovides a novel avenue to finely construct the organic microcrystals withdesired morphology for potential optoelectronics.