2D Organic Photonics: An Asymmetric Optical Waveguide inSelf-Assembled Halogen-Bonded Cocrystals
Ming-Peng Zhuo,a Yi-Chen Tao,a Xue-Dong Wang,a,* Yu-Chen Wu,c,* Shuo Chen,d Liang-Sheng Liao,a,b,* and Lei Jiangc
dKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic Engineering Shenzhen University, Shenzhen 518060, P.R. China
Anisotropic organic molecular construction and packing are crucial for the optoelectronic properties of organic crystals. Two-dimensional (2D) organic crystals with regular morphology and good photon confinement are potentially suitable for a chip-scale planar photonics system. Herein, through the bottom-up process, 2D halogen-bonded DPEpe- F4DIB cocrystals were fabricated that exhibit an asymmetric optical waveguide with the optical-loss coefficients of RBackward=0.0346 dB/μm-1 and RForward=0.0894 dB/μm-1 along the  crystal direction, which can be attributed to the unidirectional total internal reflection caused by the anisotropic molecular packing mode. Based on this crystal direction-oriented asymmetric photon transport, these as prepared 2D cocrystals have been demonstrated as a microscale optical logic gate with multiple input/out channels, which will offer potential applications as the 2D optical component for the integrated organic photonics.