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In this paper, three new donor–acceptor complex forms (zBC) containing a helical‐shape dibenzocarbazole analog (DBCz) as the electron donor and 1,2,4,5‐tetracyanobenzene (TCNB) as the electron acceptor via a simple solution‐processing strategy are reported. The beginning components self‐assembled into supramolecular frameworks with glamorous alignment modes and different molar ratios: ≈1:1 P or M‐enantiomer for α‐cocrystal, alternated P/M‐column stacking in mesmeric 2:3 β‐cocrystal, and segregated stacking of γ‐cocrystal. As a result, α‐cocrystal exhibits bright solid‐state red fluorescent, β‐cocrystal shows significant optical waveguide behavior with a low optical loss coefficient of ≈0.018 dB µm−1, and no visual light emission is observed for γ‐cocrystal under ultraviolet radiation. Interestingly, the α‐zBC crystal is not only emissive but also chiroptically active with dissymmetry factor (glum) of 0.004. This study on chiral stacking tailoring paves a way for functional design of organic charge‐transfer complex toward application in high‐performance organic optoelectronics. [ABSTRACT FROM AUTHOR]

Modern organic photonics is heavily reliant on micro‐/nanostructured organic crystalline materials, not least because they exhibit advantageous physicochemical properties and can be easily fabricated by bottom‐up approaches such as self‐assembly driven by weak noncovalent intermolecular interactions (van der Waals forces, π–π interactions, hydrogen bonds, halogen bonds, charge transfer interactions, etc.). Herein, the effects of these interactions on organic crystal nucleation are summarized, the resulting low‐dimensional organic crystal structures and their optoelectronic applications are discussed, and future development prospects are presented to inspire the further investigation of such optofunctional structures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Vapor‐phase growth methods, taking the advantages of producing high‐quality crystals with low defects, thin thickness, and homogeneous composition, are of great significance in the field of organic crystal growth and their high‐performance applications. At present, the requirements for organic crystals as building blocks for the construction of optoelectronic devices are increasing with the constant advances in organic optoelectronics. Therefore, the vapor‐phase growth method would become one of the practical techniques that cannot be ignored to fabricate organic crystals. In this paper, an overview of different vapor‐phase growth methods for the preparation of organic single crystals is provided. An introduction to the current status of the vapor phase method is presented and the view on the challenges it faces with some promising solution ideas. It is believed that this review will serve as a reference for further development and an inspiration for the new way forward. [ABSTRACT FROM AUTHOR]

Toward the evolution of integrated optoelectronic circuits, it is vital matter to realize 2D optical waveguide at micro/nanoscale. However, due to the waveguiding principle of the traditional dielectric waveguide, the transverse and longitudinal dimensions cannot be greatly reduced, thus the size of photonic apparatus is far from reaching the size level for the microelectronic device. Therefore, it is difficult to achieve a high‐level hybrid integration of integrated optical path and microelectronic circuit. However, the organic crystals with polygonal structure and hierarchical structure as the medium also can form optical waveguide by confining photons/electrons at the micro/nanoscale along different directions, and these organic microcrystals can be well applied into the ultracompact optoelectronic devices. Herein, the fabrication of organic crystals as the medium of 2D optical waveguide is briefly introduced, as well as the 2D optical waveguide phenomenon existing in these polygonal and hierarchical microcrystals. Moreover, a conclusion is drawn and expectations are expressed for the 2D optical waveguide based on organic microstructure in the near future. [ABSTRACT FROM AUTHOR]

Organic whispering‐gallery mode lasers (OWGMLs), taking the advantages of organic materials and whispering‐gallery mode (WGM) cavity, have undergone tremendous development with extensive application prospects in advanced optical fields. OWGMLs can be achieved via various strategies, typically including dope organic gain materials into WGM cavities, such as droplets, self‐assembled microcavities, and metal–organic frameworks, and utilize the self‐assembled amorphous or single‐crystalline structures of organic materials to serve simultaneously as the WGM cavity and the laser gain medium. The weak intermolecular interaction and abundant excited‐state radiative decay process of organic materials enable OWGMLs to be functionalized toward desired performance and novel applications. Here, the fundamentals related to OWGMLs as well as the advances in the strategies to realizing and functionalizing OWGMLs are introduced and reviewed. The challenges remained are discussed with perspectives and outlook provided for the future development in this exciting field. [ABSTRACT FROM AUTHOR]

The deterministic manufacturing and patterning of high‐quality organic single crystal semiconductors are core opportunities and challenges for large‐scale integrated functional devices with high efficiency and high performance. As for the solution patterning for the fabrication of the organic semiconductors, various methods are reported to efficiently control the position, alignment, and size of organic structures. Nevertheless, the poor control of the dewetting dynamics of organic solution leads to the low crystallinity and disordered crystallographic orientation of as‐fabricated organic architectures, which can limit their device performance. Herein, by use of the micropillar‐structured template with asymmetric wettability, the patterned organic 1D single crystals with precise position and geometry, flat morphology, and high alignment can be constructed. Moreover, the nanowire arrays are demonstrated with active optical waveguiding. In addition, the other patterned architectures of circle, triangle, square, pentagon, and hexagon shapes can also be constituted by regulating the surface geometry of substrates. This work not only facilitates the fundamental understanding on the patterning and crystallization of organic architectures, but also contributes greatly to the development of large‐scale assembly technology for patterning micro/nanostructures. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) organic crystals with significant advantages, such as high crystallinity, well-defined shape, and dimension-dependent optical properties, have been widely investigated in recent decades. At present, 2D organic crystals have been successfully applied to lasers, optical waveguides, organic light-emitting transistors, and organic light-emitting diodes. However, it is still a challenge for organic crystals to achieve controllable preparation, high charge mobility, and simultaneously efficient light emission because organic molecules mainly rely on noncovalent interactions (such as the van der Waals' force and the hydrogen bonding). To introduce the superior characteristics and summary the huge breakthroughs of 2D organic crystals, we herein briefly review the recent progress in terms of growth strategies and potential applications in high-performance organic photonic devices and optoelectronic devices. In addition, we present our conclusion and expectation for the future development of 2D organic crystals. [ABSTRACT FROM AUTHOR]

Abstract: Organic cocrystals formed with two or more different molecules through intermolecular noncovalent interactions, such as π–π interaction and hydrogen/halogen bonds, have received increasing attention due to their promising applications in organic optoelectronics. For organic photonics and electronics, the growth morphology of organic micro/nanocrystals coupled with their shape and emission color is of great importance. In this study, using a “cocrystal” approach, the organic microcrystals can be modulated from the yellow‐emissive polyhedral microcrystals of 1,4‐bis (4‐cyanostyryl) benzene (p‐BCB) to the sky‐blue‐emissive microwires of p‐BCB:1,4‐diiodo tetrafluorobenzene (p‐BCB:DIFB), which are self‐assembled in solution at room temperature. Additionally, with the formation of the cocrystals, the radiative decay (kr) rate of these organic microcrystals is enhanced from 0.04 to 0.12 ns−1, which is attributed to the absence of excimers in the organic cocrystals. Therefore, this “cocrystal” approach can simultaneously tune the emission color, morphology, and molecular packing mode of these as‐prepared organic microcrystals, which can contribute to the development of organic integrated optoelectronic devices. [ABSTRACT FROM AUTHOR]

Integrated microstructures composed of organic micro/nanocrystals have gained impressive interest recently as probable candidate for constructing optoelectronic circuits. However, the fabrication of these designed composite structures remains a huge challenge. Herein, the sequentially self‐assembled branched homostructures based on 1D single‐crystalline organic microrods of 1,4‐bis((E)‐4‐iodostyryl)‐2,5‐dimethoxybenzene through the facile solution‐processing approach are demonstrated. The growth mechanism of these dendritic microcrystals with an angle of 75° between trunk and branch is attributed to the facet‐selective growth principle between the (020) and (110) crystal planes, for which the interplanar spacing mismatch rate is as low as 6.1%. More significantly, this branched microstructure exhibits an asymmetric optical waveguide and can function as an optical logic gate with an ON/OFF ratio of 10.5. Therefore, the approach to build this organized multilevel structure could provide further applications as building blocks in integrated optoelectronic circuits. Sequential self‐assembly of branched 1,4‐bis((E)‐4‐iodostyryl)‐2,5‐dimethoxybenzene organic microrods is successfully achieved through the facile solution process that follows the facet‐selective growth principle. The homostructures with an angle of 75° between trunk and branch exhibit an asymmetric optical waveguide, which can further serve as an optical logic gate with an ON/OFF ratio of 10.5. [ABSTRACT FROM AUTHOR]

It has been demonstrated that organic semiconductor micro-/nanocrystals with multicolor emission/waveguide characterizations would be widely utilized as ideal building blocks for the next generation of miniaturized optical, electronic and logic operation devices. However, rational synthesis of one dimensional micro-/nanocrystals with multicolor emission and optical waveguide performances are highly desirable and still remain a challenge. Here, the DCM doped Alq 3 single-crystalline microrods are fabricated via a facile solution-exchange method. It is found that a redshift in light-emission frequency is extremely sensitive to the doping concentration of 4-(dicyano-methylene)-2-methyl-6-(4-dimethylamino-styryl)-4Hpyran (DCM) guest molecule. The green emission at 527 nm of Alq 3 is the main emitting peak when doping concentration of DCM in Alq 3 :DCM is less than 150:1. Then, when the doping concentration of DCM in Alq 3 :DCM is larger than 100:2 such as 100:10, the red emission at 635 nm becomes the dominant emitting peak, the redshift amounts can reach to roughly 108 nm. In addition, the DCM-doped Alq 3 microrods exhibit a lower optical loss of 0.019 dB/μm as a multicolored waveguide material. Therefore, it is demonstrated that the DCM-doped organic micro/nano crystals can be utilized as a promising building block for various optoelectronic components. Herein, the DCM doped Alq 3 single-crystalline microrods were controllably fabricated via a facile solution-evaporation method. It is found that a redshift in light-emission frequency is extremely sensitive to the dopant concentration of DCM guest molecule. Interestingly, when the doped ratio of Alq 3 to DCM are 100:1 and 100:1.5, there is an obvious peak at 557 nm, besides, a weak peak at 613 nm appears. In addition, the DCM:Alq 3 microrods exhibits a lower optical loss of 0.019 dB/μm as a waveguide material. [Display omitted] • The DCM doped Alq 3 single-crystalline microrods are fabricated firstly via a facile solution-exchange method. • The light-emission frequency is highly sensitive to the doping concentration of DCM guest molecule. • The DCM-doped Alq 3 microrods exhibits a lower optical loss of 0.019 dB/μm as a multicolored waveguide material. [ABSTRACT FROM AUTHOR]

Due to the unique physical and chemical properties of fullerene (C 60) molecules, micro/nanostructures of fullerene molecules have exhibited great potential in the field of optoelectronics. The growth process of C 60 micro/nanostructures can be controlled fabricated through different preparation approaches, such as liquid-liquid interface precipitation, template method. When adjusting the solvent, temperature and concentration, the morphology and the size of the C 60 micro/nanostructures will be changed. Therefore, one-dimensional structure, polygonal structure, nanoflower structure, and mesh structure can be obtained. Due to the low recombination energy and high mobility of C 60 , it also has good optoelectronic properties, and C 60 micro/nanostructures with different morphologies will also affect its optoelectronic properties. In this review, we mainly summarize the C 60 micro/nanostructures prepared by different methods and their applications in the field of optoelectronics. In the end, the perspectives for the future development are given, hopefully to provide useful guidance for the future research on C 60 micro/nanostructures. In this review, we mainly summarize the C 60 micro/nanostructures prepared by different methods and their applications in the field of optoelectronics, and give the perspectives for the future development, which may provide useful guidance for the future research on C 60 micro/nanostructures. [Display omitted] • The C 60 micro/nanostructures with specific morphologies obtained by different fabrication methods. • The C 60 micro/nanostructures' main applications in the field of optoelectronics. • Help to construct the "morphology ─ optoelectronic performance" relationship for the C 60 micro/nanostructures. • Provide useful guidance for the future research on C 60 micro/nanostructures. [ABSTRACT FROM AUTHOR]