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.
The long‐range order, no grain boundaries, low density defects, and high purity of organic semiconductor single crystals (OSSCs) make them excellent candidates for high‐performance optoelectronic devices/circuits. In this context, a systematic summary of the recent fantastic progress in the development of high‐mobility, emissive, and integrated optoelectronic OSSCs, as well as their technological devices/circuit applications is presented.
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 architectures of organic cocrystals, with long‐range order as well as free defects, offer the opportunity to unveil the structure–property and charge‐transfer–property relationships, which are beneficial to provide some general rules in rational design and choice of functional materials. In this regard, an overview of organic cocrystals in terms of assembly, containing the intermolecular interactions and growth methods, two functionality‐related factors including packing structure and charge‐transfer nature, and those advanced and novel functionalities, is presented. An outlook of future research directions and challenges for organic cocrystal is also provided.
Organic cocrystals have attracted increasing attention in the area of molecular optoelectronics, and they have provided a collaborative strategy toward functional materials. A discussion on controllable assembly for organic cocrystals is highlighted, and the structure–property and charge‐transfer–property relationships are introduced. Furthermore, advanced and novel functionalities are presented, and an outlook is provided.
Large‐scale and high‐quality 2D materials have been an emerging and promising choice for use in modern chemistry and physics owing to their fascinating property profile. The past few years have ...witnessed inspiringly progressing development in controlled fabrication of large‐sized and single‐crystal 2D materials. Among those production methods, chemical vapor deposition (CVD) has drawn the most attention because of its fine control over size and quality of 2D materials by modulating the growth conditions. Meanwhile, Cu has been widely accepted as the most popular catalyst due to its significant merit in growing monolayer 2D materials in the CVD process. Herein, very recent advances in preparing large‐sized 2D single crystals on Cu substrates by CVD are presented. First, the unique features of Cu will be given in terms of ultralow precursor solubility and feasible surface engineering. Then, scaled growth of graphene and hexagonal boron nitride (h‐BN) crystals on Cu substrates is demonstrated, wherein different kinds of Cu surfaces have been employed. Furthermore, the growth mechanism for the growth of 2D single crystals is exhibited, offering a guideline to elucidate the in‐depth growth dynamics and kinetics. Finally, relevant issues for industrial‐scale mass production of 2D single crystals are discussed and a promising future is expected.
Recent advances in the growth and production of wafer‐scale and single‐crystal 2D materials on Cu substrates by chemical vapor deposition are presented. The features and roles of Cu in making 2D crystals are comprehensively demonstrated. The daunting quest for mass production of single‐crystal 2D materials poses great potential in electronics and other applications.
A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch ...systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO3 concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO3 concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni(II)-contaminated wastewater.
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.
Assembling organic nanostructures into 2D form offers the advantages of molecular diversity, flexibility, and unique physical properties, providing exciting future prospects for optoelectronic applications. The applications of organic 2D materials for optoelectronic devices are reviewed. After a brief discussion on the protocols for 2D crystal fabrication and patterning techniques, their applications in optoelectronic devices are introduced and an outlook is provided.
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.
The heat is on: A new cocrystal with NIR photothermal properties is prepared from two small molecules, wherein the strong charge‐transfer interaction leads to active non‐radiative pathways, as revealed by femtosecond transient absorption spectroscopy.
Organic cocrystal engineering refers to two or more organic molecules stoichiometrically combined and held together by noncovalent intermolecular interactions, which differs from standard chemical ...synthesis involving covalent bond breakage and formation. Organic cocrystals have unique properties and offer a new strategy for creating enhanced organics. First, however, some key questions need to be addressed: How do diverse monomers affect the intermolecular interaction kinetics during cocrystallization? How do the intermolecular forces in cocrystals affect cocrystal functions? In this Perspective, the definition and advantages of organic cocrystal engineering, specifically in the construction of a reliable intermolecular interaction–stacking structure–performance relationship, are outlined. Additionally, recent developments in the field and the questions above are discussed. Finally, a brief conclusion and some hints on likely future developments are provided.
Organic field‐effect transistors (OFETs) are the basic elements of organic circuits towards flexible, printable, and wearable electronics. Low‐energy‐consumption OFETs with high mobility are the ...prerequisite for practical applications. After 30 years of development, OFETs have progressed rapidly, from field‐effect materials to devices, and from individual device to small‐ and medium‐scale integration. Here, a brief retrospective of OFETs' development over the past decades, and the emerging opportunities and challenges from device physics, multifunctional materials to integrated application are presented.
Low‐energy‐consumption organic field‐effect transistors (OFETs) with high mobility are the prerequisite for practical applications. After 30 years of development, OFETs have progressed rapidly, from field‐effect materials to devices, and from individual device to small‐ and medium‐scale integration. Here, a brief retrospective of OFETs' development, and the emerging opportunities, and challenges, from device physics, multifunctional materials to integrated application are presented.
Two-dimensional molecular crystals (2DMCs) are a promising candidate for flexible and large-area electronics. Their large-area production requires both low nuclei density and 2D crystal growth mode. ...As an emerging type of material, their large-area production remains a case-by-case practice. Here we present a general, efficient strategy for large-area 2DMCs. The method grows crystals on water surface to minimize the density of nuclei. By controlling the interfacial tension of the water/solution system with a phase transfer surfactant, the spreading area of the solvent increases tens of times, leading to the space-confined 2D growth of molecular crystals. As-grown sub-centimeter-sized 2DMCs floating on the water surface can be easily transferred to arbitrary substrates for device applications.
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