Tailoring the structures and photonic properties of low-dimensional organic materials by crystal engineering

Abstract

Low-dimensional organic materials have given rise to tremendous interest in optoelectronic applications, owing to their controllable photonic properties. However, the controlled-synthesis approaches for organic nano-/micro-architectures are very difficult to attain, because the weak interaction (van der Waals force) between the organic molecules cannot dominate the kinetic process of crystal growth. We report a simple method, which involves selective adhesion to the organic crystal plane by hydrogen-bonding interaction for modulating the crystal growth process, which leads either to the self-assembly of one organic molecule into two-dimensional (2D) microsheets with an obvious asymmetric light propagation or one-dimensional (1D) microrods with low propagation loss. The method of tailoring the structures and photonic properties for fabricating different micro-structures would provide enlightenment for the development of tailor-made mini-sized devices for photonic integrated circuits.

A Multilayer Film Based Selective Thermal Emitter for Infrared Stealth Technology

“…For example, 1Dpcs typically consist of dielectric films stacked periodically on substrates and have attracted extensive attention due to their high‐reflection photonic band gap (PBG). Through structural design or enhancing the density of photon states, the 1Dpcs can be utilized to control the emission spectrum . Nevertheless, the selective emission property based on tuning the PBG is poor, and the configuration complexity makes 1Dpcs unsuitable in high‐temperature environments due to the shedding of layered structures under thermal stress.…”

Optical Waveguide and Photoluminescent Polarization in Organic Cocrystal Polymorphs

“…The optical loss coefficient R is determined to be 0.211 dB mm −1 at 550 nm (Figure 3i), and the value is significantly lower than many other reported organic crystals. 56,57 Furthermore, the molecular stacking of C2 along the [100] direction is shown in Figure 3l, which is responsible for the direction of light propagation. Generally, there are two main factors that reduce the loss coefficient.…”

Optical Waveguides in Organic Crystals of Polycyclic Arenes

“…In 2018, Zhao et al synthesized a symmetric small molecule (DCF) by combing two carbazole and fluorenone together through CN bonds (Figure 21A,D). [35] Adjusting the self-assembled solvents could bring about two kinds of crystals (Figure 21B). Inherent D-A-D structural feature endowed intense orange fluorescence from these crystals.…”

“…I) The corresponding spatially resolved PL spectra of the corner. Reproduced with permission [35]. Copyright 2018, The Royal Society of Chemistry.…”