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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 cm V s 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 cm V s 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.

Highly ordered organic crystalline materials provide an ideal platform for next-generation flexible electronics.

Another benefit of dietary fiber The gut microbiome can modulate the immune system and influence the therapeutic response of cancer patients, yet the mechanisms underlying the effects of microbiota are presently unclear. Spencer et al . add to our understanding of how dietary habits affect microbiota and clinical outcomes to immunotherapy. In an observational study, the researchers found that melanoma patients reporting high fiber (prebiotic) consumption had a better response to checkpoint inhibitor immunotherapy compared with those patients reporting a low-fiber diet. The most marked benefit was observed for those patients reporting a combination of high fiber consumption and no use of over-the-counter probiotic supplements. These findings provide early insights as to how diet-related factors may influence the immune response. —PNK

A cocrystal strategy with a simple preparation process is developed to prepare novel materials for near-infrared photothermal (PT) conversion and imaging. DBTTF and TCNB are selected as electron donor (D) and electron acceptor (A) to self-assemble into new cocrystals through non-covalent interactions. The strong D-A interaction leads to a narrow band gap with NIR absorption and that both the ground state and lowest-lying excited state are charge transfer states. Under the NIR laser illumination, the temperature of the cocrystal sharply increases in a short time with high PT conversion efficiency (η=18.8 %), which is due to the active non-radiative pathways and inhibition of radiative transition process, as revealed by femtosecond transient absorption spectroscopy. This is the first PT conversion cocrystal, which not only provides insights for the development of novel PT materials, but also paves the way of designing functional materials with appealing applications.

materials, [9][10][11][12] which are crystalline singlephase materials composed of two or more different compounds generally in a stoichiometric ratio, [13] providing a platform for unveiling the structure-property relationships at a molecular level. [14] The building blocks are assembled via noncovalent interactions, offering the opportunity to achieve noncovalent synthesis of functional molecules. [15] Compared with the traditional covalent synthesis, cocrystal engineering offers numerous advantages, including: 1) avoiding complicated synthesis procedures, and cocrystal assemblies have been successfully fabricated by the vapor methods and solution-processing methods in a facile and low-cost way; 2) manipulating intermolecular interactions through selecting suitable conformers from a plentiful supply of raw materials, resulting in tunable structures, morphologies, and sizes; 3) achieving rare and multifunctional properties through a collaborative strategy in distinct constituent units, which are difficult to realize for individual components. [16][17][18] Cocrystal engineering began to draw much attention since the exploration of the metal conductive tetrathiafulvalene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) cocrystals in 1973. [19] The peculiar conductivity in organic materials makes it possible for cocrystals to serve as organic electrodes, which can effectively lower the contact resistance and further improve device performance. Encouraged by this, cocrystals can serve as a breakthrough and provide an opportunity to discover novel physicochemical properties, which are far beyond the performance of single materials. In this respect, dielectric response [20] and nonlinear optics [21,22] are also realized through rational design of each component, which is absent in their constitute components. Even more, the bottom-up supramolecular assembly provides the opportunity to equip them with the individual properties of the donor or acceptor to create multifunctional materials. [23] Typically, ambipolar charge transport can be generated by coassembling p-type semiconductors and n-type ones, and the charge-carrier mobility is now up to 1.57 cm 2 V −1 s −1 for holes and 0.47 cm 2 V −1 s −1 for electrons. [24] To date, these exciting results accelerate the investigations of organic functional cocrystals, such as room-temperature ferroelectricity, [25][26][27] optical waveguide properties, [28,29] pure organic room-temperature phosphorescent properties, [30][31][32] stimulusresponse (e.g., mechanical stress, [33,34] heat, [35,36] or solvent [37] ) characteristics, photovoltaics, [38] and near-infrared photothermal (PT) conversion and imaging, [39] etc.Cocrystal engineering with a noncovalent assembly feature by simple constituent units has inspired great interest and has emerged as an efficient and versatile route to construct functional materials, especially for the fabrication of novel and multifunctional materials, due to the collaborative strategy in the distinct constituent units. Meanwhile, the precise crystal a...

The remarkable merits of 2D materials with atomically thin structures and optoelectronic attributes have inspired great interest in integrating 2D materials into electronics and optoelectronics. Moreover, as an emerging field in the 2D-materials family, assembly of organic nanostructures into 2D forms offers the advantages of molecular diversity, intrinsic flexibility, ease of processing, light weight, and so on, providing an exciting prospect for optoelectronic applications. Herein, the applications of organic 2D materials for optoelectronic devices are a main focus. Material examples include 2D, organic, crystalline, small molecules, polymers, self-assembly monolayers, and covalent organic frameworks. The protocols for 2D-organic-crystal-fabrication and -patterning techniques are briefly discussed, then applications in optoelectronic devices are introduced in detail. Overall, an introduction to what is known and suggestions for the potential of many exciting developments are presented.

Active layer engineering, device construction, and integrated applications for infrared organic photodiodes and phototransistors are discussed in this tutorial.