Search

Considering environmental changes and the demand for more sustainable energy sources, stricter requirements have been placed on electrode materials for sodium and potassium‐ion batteries, which are expected to provide higher energy and power density while being affordable and sustainable. Vanadium sulfide‐based materials have emerged as intriguing contenders for the next generation of anode materials due to their high theoretical capacity, abundant reserves, and cost‐effectiveness. Despite these advantages, challenges such as limited cycle life and restricted ion diffusion coefficients continue to impede their effective application in sodium and potassium‐ion batteries. To overcome the limitations associated with electrochemical performance and circumvent bottlenecks imposed by the inherent properties of materials at the bulk scale, this review comprehensively summarizes and analyzes the crystal structures, modification strategies, and energy storage processes of vanadium sulfide‐based electrode materials for sodium and potassium‐ion batteries. The objective is to guide the development of high‐performance vanadium‐based sulfide electrode materials with refined morphologies and/or structures, employing environmentally friendly and cost‐efficient methods. Finally, future perspectives and research suggestions for vanadium sulfide‐based materials are presented to propel practical applications forward. [ABSTRACT FROM AUTHOR]

Stretchable and reconfigurable artificial synaptic devices with both excitatory and inhibitory properties have a wide range of applications and requirements in high‐performance neuromorphic computing and wearable electronics. Shim et al. have realized reconfigurable synaptic transistors with excitatory and inhibitory properties in the stretched state through elastic bilayer semiconductors, demonstrating great potential for neuromorphic computing. [ABSTRACT FROM AUTHOR]

The disordered chain arrangement of polymer dielectrics has complex both internal and external effects on system performance, which generally stimulates the weak acquisition and grain boundaries of vapor‐deposited organic small molecule films (VDOSMFs) with thermally activated charge transport. As a result, achieving "band‐like" transmission of VDOSMs on polymer dielectrics is attempting to prove to be a major challenge. Three types of bi‐polymer dielectrics are developed to modulate charge transport from thermally activated mode to "band‐like" transport at the interfacial level. The bottom consisting of a polyimide layer is critical to interfacial modulation, which shows the selectively binding capability with up‐dielectric layers to realize the modulation of charge transport, as corroborated by interface characterization and density functional‐based tight‐binding calculation. The findings provide an effective strategy for modulating the charge transport through polymer dielectric engineering and also recommend a podium to further comprehend the electrical characteristics of small molecules in organic thin‐film transistors. [ABSTRACT FROM AUTHOR]

Phase‐change semiconductor is one of the best candidates for designing nonvolatile memory, but it has never been realized in organic semiconductors until now. Here, a phase‐changeable and high‐mobility organic semiconductor (3,6‐DATT) is first synthesized. Benefiting from the introduction of electrostatic hydrogen bond (S···H), the molecular conformation of 3,6‐DATT crystals can be reversibly modulated by the electric field and ultraviolet irradiation. Through experimental and theoretical verification, the tiny difference in molecular conformation leads to crystalline polymorphisms and dramatically distinct charge transport properties, based on which a high‐performance organic phase‐change memory transistor (OPCMT) is constructed. The OPCMT exhibits a quick programming/erasing rate (about 3 s), long retention time (more than 2 h), and large memory window (i.e., large threshold voltage shift over 30 V). This work presents a new molecule design concept for organic semiconductors with reversible molecular conformation transition and opens a novel avenue for memory devices and other functional applications. [ABSTRACT FROM AUTHOR]

Organic semiconductors with combinative high carrier mobility and efficient solid‐state emission are full of challenges but urgently pursued for developing new emerging optoelectronics. Herein, by delicately regulating the crystal packing of an anthracene‐based molecular crystal via terminal tert‐butylation, we developed a superior high mobility emissive molecule, 2,6‐di(6‐tert‐butylnaphthyl)anthracene (TBU‐DNA). The unique "slipped herringbone" packing motif of TBU‐DNA enables its appropriate exciton‐exciton coupling and electron‐phonon coupling, thus resulting in remarkably high solid‐state emission (photoluminescence quantum yield, ΦF≈74.9 %) and efficacious charge transport (carrier mobility, μ=5.0 cm2 V−1 s−1). Furthermore, OLETs based on TBU‐DNA show an external quantum efficiency (EQE) of 1.8 %, which is among the highest EQE values for single component OLETs reported till now. This work presents a crystal engineering strategy via exquisite molecular design to realize high mobility emissive organic semiconductors. [ABSTRACT FROM AUTHOR]

It is generally believed that the incorporation of fluorine functional groups into dielectrics can effectively impede the charge‐trapping process and improve carrier mobility. However, the relationship between the device performance and fluorinated groups is still not clear and also the modulation effect of fluorine functional groups on photogenerated charge carrier in phototransistors has not yet been investigated. Herein, phototransistors are constructed by using three kinds of gate dielectric layers with different fluorinated groups to exploit the effect of fluorine functional groups. It is concluded that the presence of fluorinated groups indeed increases the transistor mobility and optical figures of merit in phototransistors compared to the device with a fluorine‐free dielectric layer. Concurrently, the exciton binding energy is increased with the addition of fluorinated groups, resulting in the decrease of phototransistor performance compared with less content of fluorinated groups due to the synergistic balance effect of fluorine functional groups. The results further clarify how the fluorine functional groups optimize the interface of organic phototransistors and modulate the photoelectric performance. [ABSTRACT FROM AUTHOR]

Integrating high charge‐carrier mobility and low‐threshold lasing action in an organic semiconductor is crucial for the realization of an electrically pumped laser, but remains a great challenge. Herein, we present an organic semiconductor, named as 2,7‐di(2‐naphthyl)‐9H‐fluorene (LD‐2), which shows an unexpected high charge‐carrier mobility of 2.7 cm2 V−1 s−1 and low‐threshold lasing characteristic of 9.43 μJ cm−2 and 9.93 μJ cm−2 and high‐quality factor (Q) of 2131 and 1684 at emission peaks of 420 and 443 nm, respectively. Detailed theoretical calculations and photophysical data analysis demonstrate that a large intermolecular transfer integral of 10.36–45.16 meV together with a fast radiative transition rate of 8.0×108 s−1 are responsible for the achievement of the superior integrated optoelectronic properties in the LD‐2 crystal. These optoelectronic performances of LD‐2 are among the highest reported low‐threshold lasing organic semiconductors with efficient charge transport, suggesting its promise for research of electrically pumped organic lasers (EPOLs). [ABSTRACT FROM AUTHOR]

Molecule design of organic semiconductors (OSCs) for eliminating photoresponse and maintaining high charge mobility concurrently is beneficial to realize intrinsically photostable and high‐performance organic field‐effect transistors (OFETs), which has never been reported. Here, a novel organic semiconductor TFP‐TT‐TPA with a centrosymmetric structure is synthesized. Remarkably, OFETs with TFP‐TT‐TPA show negligible photoresponse under light intensity up to 170.4 mW cm−2 (higher than sunlight intensity, about 138 mW cm−2), which ensures that the devices can work stably under sunlight. Through the single‐crystal structure and exciton dynamics analysis, it is found that the specific structure design can make strong intermolecular D–A interaction that occurs in the aggregate state, which facilitates the process of exciton quenching and thus enables the photostable OFETs. This study provides a new strategy for the design of organic semiconductors with intrinsic photostability and the construction of photostable organic optoelectronic devices for applications in light environment. [ABSTRACT FROM AUTHOR]

Organic phototransistors (OPTs) are playing an indispensable role in organic optoelectronics, which greatly show their promising application in optical communication, video imaging, missile guidance, and night vision. However, because the thermally activated mode dominated for thin‐film devices leads to a sharp drop in mobility at low temperatures, until now, most of the studies about OPTs are performed at room temperature, severely hindering their further potential optoelectronic application over a broad range of temperatures, especially at low temperature environment. In this work, the optoelectronic properties of a small molecule (2,6‐diphenylanthracene, DPA) based OPTs with band‐like transport are studied at low temperatures. The devices exhibit outstanding optoelectronic properties in terms of mobility (2.6 cm2 V−1 s−1), on/off ratio (≈104), detectivity (1013 Jones), and external quantum efficiency (2500%) even at 150 K, which is superior to the performance of devices with thermally activated mode. In addition, the organic photodetector at low temperatures is also fabricated. Our results demonstrate that organic π‐conjugated DPA small‐molecule has great potential in low‐temperature application. [ABSTRACT FROM AUTHOR]

Organic field‐effect transistors (OFETs) are of great significance in next‐generation optoelectronics and have made remarkable advances during the last decade. For the commercialization of OFETs, power consumption is one of the main issues needed to be addressed. To this end, OFETs with low‐voltage operation are constructed, and several strategies have been successively developed, which have attracted intensive attention for researchers to achieve this goal. In this review, we summarized the recent progress of various approaches for realizing low‐voltage OFETs, including adopting high‐k dielectrics, ultra‐thin dielectric, electrolyte dielectric, and interface engineering. Besides, the potential applications of low‐voltage OFETs in organic electronics are introduced. Finally, we give a brief outlook of this area for the future direction. [ABSTRACT FROM AUTHOR]

Stretchable organic field‐effect transistors (OFETs) are one of the essential building blocks for next‐generation wearable electronics due to the high stretchability of OFET well matching with the large deformation of human skin. In recent years, some significant progress of stretchable OFETs have already been made via the strategies of stretchable molecular design and geometry engineering. However, the main opportunity and challenge of stretchable OFETs is still to simultaneously improve their stretchability and mobility. This review covers the recent advances in the research of stretchable OFETs with high mobility. First, the core stretchable materials are summarized, including organic semiconductors, electrodes, dielectrics, and substrates. Second, the materials and healing mechanism of self‐healing OFET are summarized in detail. Subsequently, their different configurations and the potential applications are summarized. Finally, an outlook of future research directions and challenges in this area is presented. [ABSTRACT FROM AUTHOR]

Polyimide memory materials with a donor–acceptor structure based on a charge‐transfer mechanism exhibit great potential for next‐generation information storage technology due to their outstanding high‐temperature resistance and good dimensional and chemical stability. Precisely controlling memory performance by limited chemical decoration is one of core challenges in this field. Most reported work mainly focuses on designing novel and elaborate electron donors or acceptors for the expected memory behavior of polyimides; this takes a lot of time and is not always efficacious. Herein, we report a series of porphyrinated copolyimides coPI−Znx (x=5, 10, 20, 50, 80), where x represents the mole percentage of Zn ion in the central core of the porphyrin. Experimental and theoretical analysis indicate that the Zn ion could play a vital bridge role in promoting the formation and stabilization of a charge‐transfer complex by enhancing the hybridization of local and charge transfer (HLCT) excitations of porphyrinated polyimides, endowing coPI−Znx with volatile random access memory performance and continuously tunable retention time. This work could provide one simple strategy to precisely regulate memory performance merely by altering the metal content in porphyrinated polyimides. [ABSTRACT FROM AUTHOR]

The functionalization of polymer dielectrics with self‐assembly monolayer is still a big issue to be resolved due to the lack of particular anchoring sites on their surface for specific binding. To this end, hydroxyl groups are a kind of commonly used anchoring sites, which can be effectively produced on polymer surface by oxygen plasma treatment. In this work, the modification methods are investigated and the assembly conditions of self‐assembly monolayer are characterized on the surface of low‐k polyimide (PI) gate dielectric layers. As a result, the device performance can be enhanced by an order of magnitude under the optimal modified state compared with the initial state. In addition, the charge transport mechanism of organic semiconductor on PI surface is studied through temperature‐variable experiments. Furthermore, organic logic circuits (NAND gate, NOR gate, inverter, and oscillator) are manufactured using modified PI as insulating layers. The functionalization of polymer dielectrics with self‐assembly monolayer offers an effective strategy to improve the device performance in organic electronics. [ABSTRACT FROM AUTHOR]

Fullerene assembling with specific donor molecules would yield multifunctional metamaterials via the collective behavior, wherein linear acenes are widely used as donor molecules to construct the charge‐transfer heterojunction structure with fullerene. However, they are generally prepared by vacuum deposition due to the insoluble property of high‐performance linear acenes molecules in common solvents, which makes the construction of fullerene with insoluble donor molecules still be a big challenge in the solution‐processed method. To this end, chemical modification provides an effective solution‐processed strategy to construct donor and acceptor systems. Here, the C60‐pentacene is assembled into controllable flower‐like superstructures by the surface grafting method. It is found that the nanofeatures of the microflowers could be regulated by temperature, resulting in dense‐flakes morphology at room temperature and loose flakes at high temperatures. Furthermore, the dense‐flakes microflowers structures with less mass but better crystalline structure exhibit better optoelectronic properties. Our results reveal an effective control on the nanofeatures of the self‐assembled fullerenes complex superstructures and their role for the optoelectronic performance, which may promote the exploring of fullerene superstructures as photodetectors. [ABSTRACT FROM AUTHOR]

Phototransistors combine light detection and signal amplification functions into a single device and are regarded as one of the most important components for optoelectronic integration. In recent years, organic phototransistors (OPTs) have attracted worldwide interest because of their potential advantages of low cost, light weight, excellent flexibility and broadband detection. In this review, a brief description of the working mechanisms and performance metrics of OPTs is presented. Afterwards, the recent progress of OPTs based on the conventional planar field‐effect transistor structure is presented. Furthermore, from the perspective of novel device architectures and interface engineering, strategies for improving the performance of OPTs are discussed. Flexible optoelectronic devices based on OPTs for potential application in next‐generation wearable and human‐friendly electronics are also highlighted. Finally, an outlook for future research directions and challenges for OPTs is provided. [ABSTRACT FROM AUTHOR]

Abstract: The +6 oxidation state of iron generally exists in the form of ferrate(VI) with high redox potential and environmentally friendly nature. Although ferrate(VI) has been known for over a century, its chemistry is still limited to the solvent‐based reactions that suffers from the insolubility/instability of this oxidant and the environmental issues caused by hazardous solvents. Herein, we explore the solvent‐free reactivity of ferrate(VI) under mechanical milling, revealing that its strong oxidizing power is accessible in the “dry” solid state towards a broad variety of substrates, for example, aromatic alcohols/aldehydes and carbon nanotubes. More significantly, solvent‐free mechanochemistry also reshapes the oxidizing ability of ferrate(VI) due to the underlying solvent‐free effect and the promotive mechanical actions. This study opens up a new chemistry of ferrate(VI) with promising application in green oxidative transformation of both organic and inorganic substrates. [ABSTRACT FROM AUTHOR]

The article discusses a study focusing on the use of nanosphere lithography to generate nanogap electrodes and arrays between pre-patterned electrodes. Topics discussed include the self-assembling characteristic of polystyrene nanospheres; the process of electron-beam lithography; and the use of sodium dodecyl sulfate (SDS) for self-assembling polystyrene nanospheres. Also mentioned is the use of photoresist polymethyl methacrylate in the study.

The article focuses on issue of charge injection which enables to investigate the mechanism of charge transport of nanopore structured silver electrodes in bottom-gate bottom-contact (BGBC) of organic field effect transistors (OFET). Topics discussed include use of scanning Kelvin probe microscopy (SKPM) to detect the condition of the local electric potential, nanopore electrodes induce the growth of pentacene with a reduced number of grain boundaries and performance in organic electronics.

Keywords: Charge Transport; Crystal Engineering; Light Emission; Molecular Crystals; Organic Semiconductor EN Charge Transport Crystal Engineering Light Emission Molecular Crystals Organic Semiconductor 1 1 1 11/03/22 20221107 NES 221107 B An anthracene-based molecular crystal b with a unique "slipped herringbone" packing motif was developed by crystal engineering through terminal I tert i -butylation. Appropriate exciton-exciton coupling/electron-phonon coupling originating from the unique crystal packing induces a remarkably strong solid-state emission and efficient charge transport, as reported by Wenping Hu et al. in their Research Article (e202206825). Appropriate exciton-exciton coupling/electron-phonon coupling originating from the unique crystal packing induces a remarkably strong solid-state emission and efficient charge transport, as reported by Wenping Hu et al. in their Research Article (e202206825). [Extracted from the article]

Nanosphere lithography is used to process nanopore-structured electrodes, which are applied into the fabrication of bottom-gate, bottom-contact configuration organic field effect transistors (OFETs) to serve as source/drain elecrodes. The introduction of this nanopore-structure electrode facilitates the forming of nanopore-structure pentacene layers with small grain boundaries at the electrode interface, and then reduces the contact resistance, contactinduces the growth of pentacene and accordingly improves the mobility of charge carriers in the OFETs about 20 times as compared with results in literature through enhancing the charge carrier injection. It is believed that this structure of electrode is a valuable approach for improving organic filed effect transistors. [ABSTRACT FROM AUTHOR]

'Regioselectivity deposition' method is developed to pattern silver electrodes facilely and efficiently by solution-process with high resolution (down to 2 μm) on different substrates in A4 paper size. With the help of this method, large-area, flexible, high-performance polymer field-effect transistors based on the silver electrodes and polyimide insulator are fabricated with bottom-contact configuration by all-solution processes. The polymer devices exhibit high performance with average field-effect mobility over 1.0 cm2 V−1 s−1 (the highest mobility up to 1.5 cm2 V−1 s−1) and excellent environmental stability and flexibility, indicating the cost effectiveness of this method for practical applications in organic electronics. [ABSTRACT FROM AUTHOR]

Organic circuits, organic field-effect transistors (OFETs), polyimide, self-assembled monolayer, surface modification Functionalization of Polymer Dielectrics: Functionalization of Low-k Polyimide Gate Dielectrics with Self-Assembly Monolayer Toward High-Performance Organic Field-Effect Transistors and Circuits (Adv. Keywords: organic circuits; organic field-effect transistors (OFETs); polyimide; self-assembled monolayer; surface modification EN organic circuits organic field-effect transistors (OFETs) polyimide self-assembled monolayer surface modification 1 1 1 06/12/21 20210609 NES 210609 In article number 2100217, Jie Li, Ye Zou, Deyang Ji, Liqiang Li, and co-workers report the functionalization of polyimide dielectrics with orderly self-assembly monolayer, which promotes ordered growth of the semiconductor for enhancing the device performance by an order of magnitude. [Extracted from the article]

The study of monolayer organic field‐effect transistors (MOFETs) provides an effective way to investigate the intrinsic charge transport of semiconductors. To date, the research based on organic monolayers on polymeric dielectrics lays far behind that on inorganic dielectrics and the realization of a bulk‐like carrier mobility on pure polymer dielectrics is still a formidable challenge for MOFETs. Herein, a quasi‐monolayer coverage of pentacene film with orthorhombic phase is grown on the poly (amic acid) (PAA) dielectric layer. More significantly, charge density redistribution occurs at the interface between the pentacene and PAA caused by electron transfer from pentacene to the PAA dielectric layer, which is verified by theoretical simulations and experiments. As a consequence, an enhanced hole accumulation layer is formed and pentacene‐based MOFETs on pure polymer dielectrics exhibit bulk‐like carrier mobilities of up to 13.7 cm2 V−1 s−1 from the saturation region at low VGS, 9.1 cm2 V−1 s−1 at high VGS and 7.6 cm2 V−1 s−1 from the linear region, which presents one of the best results of previously reported MOFETs so far and indicates that the monolayer semiconductor growing on pure polymer dielectric could produce highly efficient charge transport. [ABSTRACT FROM AUTHOR]

The increasing amount of electronic exerts a profound impact on both the environment and human health. Looking forward, it is imperative to develop electronic products that can degrade under mind condition, which largely relies on the development of degradable organic semiconductors (OSCs). Yet, designing degradable OSCs with decent electrical properties is challenging. In this study, two degradable n‐type OSCs based on a dynamic covalent C═C bond formed via the Knoevenagel condensation reaction are reported. The cleavage of Knoevenagel formed C═C bond through a retro‐Knoevenagel process imparts the degradability of these two OSCs in the weak base, particularly in the human‐friendly α‐amino acid of lysine. Meanwhile, the C═C bond formed by Knoevenagel reaction preserves optimal backbone planarity and good electron delocalization of the molecules. This, in turn, endows the OSCs with commendable electron transport performance, achieving an electron mobility of up to 0.57 cm2 V⁻¹ s⁻¹ in organic thin‐film transistors. This work provides a new insight into the molecular design strategy for the development of OSCs with degradability and good electrical properties. [ABSTRACT FROM AUTHOR]

Small reaction, big application! The silver mirror reaction is a straightforward way to produce silver films, and can be performed using cheap reactants in aqueous solutions. Here, it is successfully introduced into organic electronics by L. Jiang, H. Dong, G. Yu, W. Hu, and co‐workers, and applied to the process of fabricating flexible, high‐performance, large‐area, all‐solution‐processable organic fieldeffect transistors at room temperature with high resolution. [ABSTRACT FROM AUTHOR]