https://www.pnas.org/content/pnas/90/5/1635.full.pdf

Supramolecular chemistry.

Organic semiconducting single crystals (OSSCs) are ideal candidates for the construction of high-performance optoelectronic devices/circuits and a great platform for fundamental research due to their long-range order, absence of grain boundaries, and extremely low defect density. Impressive improvements have recently been made in organic optoelectronics: the charge-carrier mobility is now over 10 cm2 V-1 s-1 and the fluorescence efficiency reaches 90% for many OSSCs. Moreover, high mobility and strong emission can be integrated into a single OSSC, for example, showing a mobility of up to 34 cm2 V-1 s-1 and a photoluminescence yield of 41.2%. These achievements are attributed to the rational design and synthesis of organic semiconductors as well as improvements in preparation technology for crystals, which accelerate the application of OSSCs in devices and circuits, such as organic field-effect transistors, organic photodetectors, organic photovoltaics, organic light-emitting diodes, organic light-emitting transistors, and even electrically pumped organic lasers. In this context, an overview of these fantastic advancements in terms of the fundamental insights into developing high-performance organic semiconductors, efficient strategies for yielding desirable high-quality OSSCs, and their applications in optoelectronic devices and circuits is presented. Finally, an overview of the development of OSSCs along with current challenges and future research directions is provided.

Organic Semiconductor Single Crystals for Electronics and Photonics.

Supramolecular materials held together by noncovalent interactions, such as hydrogen bonding, host-guest interactions, and electrostatic interactions, have great potential in material science. The unique reversibility and adaptivity of noncovalent intreractions have brought about fascinating new functions that are not available by their covalent counterparts and have greatly enriched the realm of functional materials. This review article aims to highlight the very recent and important progresses in the area of functional supramoleuclar materials, focusing on adaptive mechanical materials, smart sensors with enhanced selectivity, soft luminescent and electronic nanomaterials, and biomimetic and biomedical materials with tailored structures and functions. We cannot write a complete account of all the interesting work in this area in one article, but we hope that it can in a way reflect the current situation and future trends in this prosperously developing area of functional supramolecular materials.

25th anniversary article: reversible and adaptive functional supramolecular materials: "noncovalent interaction" matters.

The features of well-conjugated and planar aromatic structures make π-conjugated luminescent materials suffer from aggregation caused quenching (ACQ) effect when used in solid or aggregated states, which greatly impedes their applications in optoelectronic devices and biological applications. Herein, we reduce the ACQ effect by demonstrating a facile and low cost method to co-assemble polycyclic aromatic hydrocarbon (PAH) chromophores and octafluoronaphthalene together. Significantly, the solid photoluminescence quantum yield (PLQYs) for the as-resulted four micro/nanococrystals are enhanced by 254%, 235%, 474 and 582%, respectively. Protection from hydrophilic polymer chains (P123 (PEO20-PPO70-PEO20)) endows the cocrystals with superb dispersibility in water. More importantly, profiting from the above-mentioned highly improved properties, nano-cocrystals present good biocompatibility and considerable cell imaging performance. This research provides a simple method to enhance the emission, biocompatibility and cellular permeability of common chromophores, which may open more avenues for the applications of originally non- or poor fluorescent PAHs.

/pdf/reducing-aggregation-caused-quenching-effect-through-co-7361ras43j.pdf

Reducing aggregation caused quenching effect through co-assembly of PAH chromophores and molecular barriers

ConspectusOrganic donor–acceptor (DA) complexes have attracted wide attention in recent decades, resulting in the rapid development of organic binary system electronics. The design and synthesis of organic DA complexes with a variety of component structures have mainly focused on metallicity (or even superconductivity), emission, or ferroelectricity studies. Further efforts have been made in high-performance electronic investigations. The chemical versatility of organic semiconductors provides DA complexes with a great number of possibilities for semiconducting applications. Organic DA complexes extend the semiconductor family and promote charge separation and transport in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). In OFETs, the organic complex serves as an active layer across extraordinary charge pathways, ensuring the efficient transport of induced charges.Although an increasing number of organic semiconductors have been reported to exhibit good p- or n-type properties (m...

/pdf/organic-donor-acceptor-complexes-as-novel-organic-4bzh7p0vbx.pdf

Organic Donor–Acceptor Complexes as Novel Organic Semiconductors

Self-assembled microtubes of mixed charge-transfer (CT) complexes comprising TCNB and naphthalene can be constructed with pyrene as dopant by an etching-assisted CT-induced interaction. Highly efficient Forster resonance energy transfer (FRET) from the excited naphthalene-TCNB to pyrene-TCNB molecules is obtained in mixed CT complex microtubes. White-light emissive CT complex microtubes can be formed by adjusting the dopant concentration and serve as an active optical waveguide.

White-light emitting microtubes of mixed organic charge-transfer complexes.

Two typical types of luminescent organic cocrystals comprising pyrene-octafluoronaphthalene (pyrene-OFN) and pyrene-1,2,4,5-tetracyanobezene (pyrene-TCNB) were developed by a simple supramolecular assembly strategy The cocrystals exhibit distinct optical properties because of their different intermolecular interaction modes; that is, arene-perfluoroarene (AP) and charge-transfer (CT) interactions Unexpectedly, a pyrene-TCNB system with strong CT interactions was incorporated into a pyrene-OFN host as a robust guest to generate white-light emission (WLE) In the supramolecular cocrystal system, an efficient energy-transfer process from pyrene-OFN to pyrene-TCNB occurred because of the well-matched spectra of the constituents and a desirable energy donor/acceptor (D/A) distance The present competitive intermolecular interaction strategy could be applied to the fabrication of more complicated organic light-harvesting systems

Competition between Arene–Perfluoroarene and Charge-Transfer Interactions in Organic Light-Harvesting Systems

We report here a new ternary solvated (perylene-TCNB)·2THF cocrystal, which can transform into binary perylene-TCNB cocrystal reversibly by successive desorption or absorption of THF solvent. As a consequence, macroscopic mechanical bending would be realized when repeated stimulation with THF solvent. The present results clearly demonstrated that solvent induced mechanical bending is driven by structural change at the molecular scale. Such solvatomechanical bending behavior is clearly revealed for the first time.

Solvatomechanical Bending of Organic Charge Transfer Cocrystal

A series of crystalline mixed cocrystal microtubes comprising organic charge-transfer (CT) complexes has been prepared. The emission colors of the mixed cocrystal microtubes can be tailored from green to orange at low dopant concentrations (0 < x ⩽ 5%), while their hexagonal cross sections can transform into square ones gradually at higher concentrations (0.15 < x < 1). In addition, we can further extend the solvent-processed synthetic route to other CT pairs based on structural compatibility consideration.

Charge-Transfer Emission of Mixed Organic Cocrystal Microtubes over the Whole Composition Range

Integrating together two dissimilar π-conjugated molecules into controlled complex topological configurations remains a largely unsolved problem owing to the diversity of organic species and their respective different assembly features. Here, we find that two structurally similar organic semiconductors, 9,10-bis(phenylethynyl)anthracene (BA) and 5,12-bis(phenylethynyl)naphthacene (BN), co-assemble into two-component helices by control of the growth kinetics as well as the molar ratio of BA/BN. The helical superstructures made of planar and twisted bis(phenylethynyl) derivatives can be regarded as (BA)x(BN)1-x alloys, which are formed due to compatible structural relationship between BA and BN. Moreover, epitaxial growth of (BA)x(BN)1-x alloy layer on the surface of BA tube to form BA@(BA)x(BN)1-x core-shell structure is also achieved via a solute exchange process. The precise control over composition and morphology towards organic alloy helices and core-shell microstructures opens a door for understanding the complex co-assembly features of two or more different material partners with similar structures.

/pdf/complex-assembly-from-planar-and-twisted-p-conjugated-55yugvmic7.pdf

Yilong Lei

Papers

White-light emitting microtubes of mixed organic charge-transfer complexes.

Competition between Arene–Perfluoroarene and Charge-Transfer Interactions in Organic Light-Harvesting Systems

Solvatomechanical Bending of Organic Charge Transfer Cocrystal

Charge-Transfer Emission of Mixed Organic Cocrystal Microtubes over the Whole Composition Range

Complex assembly from planar and twisted π-conjugated molecules towards alloy helices and core-shell structures.