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.
High‐purity semiconducting single‐walled carbon nanotubes (s‐SWCNTs) are of paramount significance for the construction of next‐generation electronics. Until now, a number of elaborate sorting and ...purification techniques for s‐SWCNTs have been developed, among which solution‐based sorting methods show unique merits in the scale production, high purity, and large‐area film formation. Here, the recent progress in the solution processing of s‐SWCNTs and their application in electronic devices is systematically reviewed. First, the solution‐based sorting and purification of s‐SWCNTs are described, and particular attention is paid to the recent advance in the conjugated polymer‐based sorting strategy. Subsequently, the solution‐based deposition and morphology control of a s‐SWCNT thin film on a surface are introduced, which focus on the strategies for network formation and alignment of SWCNTs. Then, the recent advances in electronic devices based on s‐SWCNTs are reviewed with emphasis on nanoscale s‐SWCNTs' high‐performance integrated circuits and s‐SWCNT‐based thin‐film transistors (TFT) array and circuits. Lastly, the existing challenges and development trends for the s‐SWCNTs and electronic devices are briefly discussed. The aim is to provide some useful information and inspiration for the sorting and purification of s‐SWCNTs, as well as the construction of electronic devices with s‐SWCNTs.
High‐purity semiconducting single‐walled carbon nanotubes (s‐SWCNTs) are crucial for electronic applications. Recent significant progress in the solution sorting/processing of s‐SWCNTs and their application in electronic devices is systematically summarized, giving deep insight into the principles and trends for solution sorting/processing of s‐SWCNTs based on the demands of electronic applications.
Polymer-based gate dielectrics have received growing attention due to their important role in field-effect transistors (OFETs). This review article aims to present the recent progress of polymer ...dielectrics for high-performance OFET applications. We first discuss the requirements for polymer dielectrics in tailoring the overall performance of OFETs from the perspective of both bulk material properties and surface characteristics of the polymers. On this basis, we introduce the design strategies and desired processing techniques of polymer dielectrics for optimizing the charge transport and stabilizing the operation of OFETs. Then, we highlight the recent advances in polymer-based dielectrics by classifying and comparing different categories of polymeric materials as well as polymer nanocomposites, and focus is also given to elucidating the critical relationships between polymer structures, gate dielectric properties and OFET performance. Finally, a perspective of future research directions and challenges for polymer dielectrics is provided.
With the decreased sizes of microelectronic devices, the excess heat has become one of the most important factors that shorten the lifetime of electronic components. As a result, developing materials ...with high-thermal conductivity is an urgent issue. In this study, we combine an ultrasonic exfoliation and evaporated self-assembly methods to prepare boron nitride nanosheets (BNNS)/thermoplastic polyurethane (TPU) composites with small (S) and large (L) sizes connected BNNS as additives. Our results indicate that BNNS/TPU nanocomposites have better thermal conductivity than TPU, and the optimum performance is achieved at 10 wt% BNNS(S/L-1/9)/TPU. This enhanced thermal conductivity is ascribed to the successful construction of effective thermal conductive pathway. The S-BNNS is connected to the adjacent L-BNNS in TPU, which can also form a dense structure. The formation of the continuous thermal conductive pathways and networks structure facilitate the heat diffusion throughout the composites, which are the key to achieving high thermal conductivity in polymer composites. Furthermore, these results may be helpful to the deeper understanding for the combined structure of fillers in polymer matrix, which will expand the scope of applications for these materials.
The piezoresistive pressure sensor, a kind of widely investigated artificial device to transfer force stimuli to electrical signals, generally consists of one or more kinds of conducting materials. ...Here, a highly sensitive pressure sensor based on the semiconductor/conductor interface piezoresistive effect is successfully demonstrated by using organic transistor geometry. Because of the efficient combination of the piezoresistive effect and field‐effect modulation in a single sensor, this pressure sensor shows excellent performance, such as high sensitivity (514 kPa−1), low limit of detection, short response and recovery time, and robust stability. More importantly, the unique gate modulation effect in the transistor endows the sensor with an unparalleled ability—tunable sensitivity via bias conditions in a single sensor, which is of great significance for applications in complex pressure environments. The novel working principle and high performance represent significant progress in the field of pressure sensors.
A highly sensitive pressure sensor based on the semiconductor/conductor interface piezoresistive effect in organic field‐effect transistors is demonstrated. This sensor simultaneously displays high and tunable sensitivity due to combining the advantages of the piezoresistive effect and the field‐effect modulation. In addition, the quick response speed and robust working performance show its potential in subtle and complex pressure environments.
High performance organic field‐effect transistor (OFET)‐based ammonia sensors are demonstrated with ultrathin (4–6 molecular layers) dendritic microstripes of an organic semiconductor prepared via ...dip‐coating. These sensors exhibit high sensitivity, fast response/recovery rate, good selectivity, low concentration detection ability, and reliable reversibility, as well as stability. Such a performance represents great progress in the field of OFET‐based sensors.
High-dielectric-constant (high-
k
) polymers are highly desirable for energy storage and dielectric applications in power systems and microelectronic devices because of their easy processing and ...flexibility. However, the enhancement of
k
is usually at the cost of other undesirable properties such as increase of dielectric loss and leakage currents and decrease of breakdown strength. Herein, using reversible-addition fragmentation chain transfer (RAFT) polymerization, we report a series of novel low-temperature crosslinkable high-
k
copolymers, poly(2-(methylsulfonyl)ethyl methacrylate-
co
-glycidyl methacrylate) (poly(MSEMA-
co
-GMA)), which exhibit
k
values about 9–12. The crosslinking significantly enhances the breakdown strength (
E
b
≈ 500 MV m
−1
), suppresses the leakage currents and improves the solvent resistance. The excellent dielectric performance makes the copolymers have both high energy storage capability and high energy efficiency. The discharged energy density reached 12.5 J cm
−3
at 500 MV m
−1
. Noticeably, an efficiency higher than 85% was maintained even at a high field of 400 MV m
−1
, which is much higher than those of poly(vinylidene fluoride) (PVDF) based ferroelectric polymers with comparable
k
. Furthermore, the poly(MSEMA-
co
-GMA) copolymers were successfully applied as dielectric layers for organic field-effect transistors (OFETs) to realize low-voltage operation.
Nanospheres lithography (NSL) is an economical technique, which makes use of highly monodispersed nanospheres such as deposition or etch masks for generating patterns with nanoscale features. ...Embedding nanostructures into organic electronic devices can endow them with unique capabilities and enhanced performance, which have greatly advanced the development of organic electronics. In this review, a brief summary of the methods for the preparation of monodispersed nanospheres is presented. Afterward, the authors highlight the recent advances of a wide variety of applications of nanospheres lithography in organic electronic devices. Finally, the challenges in this field are pointed out, and the future development of this field is discussed.
This review comprehensively summarizes recent advances of nanospheres lithography in organic electronics, including their applications in versatile organic electronic devices, such as organic field‐effect transistors (OFETs), OFET‐based sensors, vertical organic light‐emitting transistors (VOLETs), organic light emitting diodes (OLEDs), organic photovoltaic devices (OPVs), and some new emerging organic electronic devices.
Ultrathin film with thickness below 15 nm of organic semiconductors provides excellent platform for some fundamental research and practical applications in the field of organic electronics. However, ...it is quite challenging to develop a general principle for the growth of uniform and continuous ultrathin film over large area. Dip-coating is a useful technique to prepare diverse structures of organic semiconductors, but the assembly of organic semiconductors in dip-coating is quite complicated, and there are no reports about the core rules for the growth of ultrathin film via dip-coating until now. In this work, we develop a general strategy for the growth of ultrathin film of organic semiconductor via dip-coating, which provides a relatively facile model to analyze the growth behavior. The balance between the three direct factors (nucleation rate, assembly rate, and recession rate) is the key to determine the growth of ultrathin film. Under the direction of this rule, ultrathin films of four organic semiconductors are obtained. The field-effect transistors constructed on the ultrathin film show good field-effect property. This work provides a general principle and systematic guideline to prepare ultrathin film of organic semiconductors via dip-coating, which would be highly meaningful for organic electronics as well as for the assembly of other materials via solution processes.
We have surveyed avian influenza virus (AIV) genomes from live poultry markets within China since 2014. Here we present a total of 16,091 samples that were collected from May 2016 to February 2019 in ...23 provinces and municipalities in China. We identify 2048 AIV-positive samples and perform next generation sequencing. AIV-positive rates (12.73%) from samples had decreased substantially since 2016, compared to that during 2014-2016 (26.90%). Additionally, H9N2 has replaced H5N6 and H7N9 as the dominant AIV subtype in both chickens and ducks. Notably, novel reassortants and variants continually emerged and disseminated in avian populations, including H7N3, H9N9, H9N6 and H5N6 variants. Importantly, almost all of the H9 AIVs and many H7N9 and H6N2 strains prefer human-type receptors, posing an increased risk for human infections. In summary, our nation-wide surveillance highlights substantial changes in the circulation of AIVs since 2016, which greatly impacts the prevention and control of AIVs in China and worldwide.
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