Near-infrared organic photodetectors (NIR OPDs) own some unique properties such as tailorable optoelectronic properties, ease of processing, compatibility with flexible substrates, and operation at ...room temperature. Therefore, NIR OPDs are attractive candidates for future electronic products due to the increasingly desired for wearable electronic devices and biomedical applications. In order to fulfill this goal, it is extremely necessary to fabricate high-performance NIR OPDs. In this review, we present a broad overview of advances in NIR OPDs from the perspective of material selection and device performance optimization over the past decade, and we also summarize the potential applications of NIR OPDs. At last, we undergo a deep discussion about the challenges and prospects for the future development of organic NIR OPDs.
The advantages of organic field‐effect transistors, such as low cost, mechanical flexibility and large‐area fabrication, make them potentially useful for electronic applications such as flexible ...switching backplanes for video displays, radio frequency identifications and so on. A large amount of molecules were designed and synthesized for electron transporting (n‐type) and ambipolar organic semiconductors with improved performance and stability. In this review, we focus on the advances in performance and molecular design of n‐type and ambipolar semiconductors reported in the past few years.
This review focuses on the advances in n‐type and ambipolar semiconductors reported in the past few years. n‐Type and ambipolar semiconducting materials designed for high‐performance OFETs are classified by their chemical structures. The relationships between the chemical structure, energy level, transistor characteristics, stability, etc. are discussed.
Graphene, a two‐dimensional material, is regarded as one of the most promising candidates for future nanoelectronics due to its atomic thickness, excellent properties and widespread applications. As ...the first step to investigate its properties and finally to realize the practical applications, graphene must be synthesized in a controllable manner. Thus, controllable synthesis is of great significance, and received more and more attention recently. This Progress Report highlights recent advances in controllable synthesis of graphene, clarifies the problems, and prospects the future development in this field. The applications of the controllable synthesis are also discussed.
Controllable synthesis of graphene is of great importance for both foundational researches and practical applications. This Progress Report summarizes recent advances in synthesizing graphene with controlled sizes, shapes, edges, layers, doping, and assembly, discusses their applications, and clarifies the problems and prospects the future development. It will be valuable for the development of research in this field.
The progress of neural synaptic devices is experiencing an era of explosive growth. Given that the traditional storage system has yet to overcome the von Neumann bottleneck, it is critical to develop ...hardware with bioinspired information processing functions and lower power consumption. Transistors based on 2D materials, metal oxides, and organic materials have been adopted to mimic the synapse of a human brain, due to their high plasticity, parallel computing, integrated storage, and system information processing. Among these materials used to build transistors, organic semiconductors are considered to be the most promising candidate for neural synaptic devices and bio‐electronics, owing to their easy processing, mechanical flexibility, low cost, good bio‐compatibility, and ductility. This review focuses on the recent advances in organic synaptic devices with various structures, materials, and working mechanisms. The applications of artificial neural networks that integrate multiple organic synaptic transistors are also concretely discussed. Finally, the challenges that organic synaptic devices currently face are discussed and future developments are forecast.
This review focuses on recent progress in organic synaptic devices. The organic materials used in synaptic devices, device structures, working mechanisms, and applications for organic‐based artificial neural systems are reviewed. The current problems and future perspectives regarding this emerging area are also discussed.
High‐performance ambipolar and electronic type semiconducting polymers are essential for fabricating various organic optoelectronic devices and complementary circuits. This review summarizes the ...strategies of improving the electron transport of semiconducting polymers via acceptor modulation strategies, which include the use of single, dual, triple, multiple, and all acceptors as well as the fusion of multiple identical acceptors to obtain new heterocyclic acceptors. To further improve the electron transport of semiconducting polymers, the introduction of strong electron‐withdrawing groups can enhance the electron‐withdrawing ability of donors and acceptors, thereby facilitating electron injection and suppressing hole accumulation. In addition, the relationships between the molecular structure, frontier molecular orbital energy levels, thin film morphology, microstructure, processing conditions, and device performances are also comprehensively discussed. Finally, the challenges encountered in this research area are proposed and the future outlook is presented.
This review illustrates the significance of improving electron transport of semiconducting polymers. To improve the electron mobilities, acceptor modulation strategies are summarized and discussed. The introduction of electron‐withdrawing groups into polymers is also involved. High‐performance organic field‐effect transistors are reviewed. The relationship between device performance and chemical structure, energy levels, molecular packing orientation, and processing condition is comprehensively discussed.
The enhancement of catalytic performance of cobalt phosphide-based catalysts for the hydrogen evolution reaction (HER) is still challenging. In this work, the doping effect of some transition metal ...(M = Fe, Ni, Cu) on the electrocatalytic performance of the M–Co2P/NCNTs (NCNTs, nitrogen-doped carbon nanotubes) hybrid catalysts for the HER was studied systematically. The M–Co2P/NCNTs hybrid catalysts were synthesized via a simple in situ thermal decomposition process. A series of techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, transmission electron microscopy, and N2 sorption were used to characterize the as-synthesized M–Co2P/NCNTs hybrid catalysts. Electrochemical measurements showed the catalytic performance according to the following order of Fe–Co2P/NCNTs > Ni–Co2P/NCNTs > Cu–Co2P/NCNTs, which can be ascribed to the difference of structure, morphology, and electronic property after doping. The doping of Fe atoms promote the growth of the 111 crystal plane, resulting in a large specific area and exposing more catalytic active sites. Meanwhile, the Feδ+ has the highest positive charge among all the M–Co2P/NCNTs hybrid catalysts after doping. All these changes can be used to contribute the highest electrocatalytic activity of the Fe–Co2P/NCNTs hybrid catalyst for HER. Furthermore, an optimal HER electrocatalytic activity was obtained by adjusting the doping ratio of Fe atoms. Our current research indicates that the doping of metal is also an important strategy to improve the electrocatalytic activity for the HER.
Particular attention has been focused on n‐channel organic thin‐film transistors (OTFTs) during the last few years, and the potentially cost‐effective circuitry‐based applications in flexible ...electronics, such as flexible radiofrequency identity tags, smart labels, and simple displays, will benefit from this fast development. This article reviews recent progress in performance and molecular design of n‐channel semiconductors in the past five years, and limitations and practicable solutions for n‐channel OTFTs are dealt with from the viewpoint of OTFT constitution and geometry, molecular design, and thin‐film growth conditions. Strategy methodology is especially highlighted with an aim to investigate basic issues in this field.
Recent progress in the performance and molecular design of n‐channel semiconductors during the past five years is summarized. The limitations and practicable solutions for n‐channel organic thin‐film transistors (OTFTs) are dealt with from the viewpoint of OTFT constitution and geometry, molecular design, and thin‐film growth conditions. Strategies for methodology are especially highlighted with an aim to investigate basic issues in this field.
We analyze the polarization content of gravitational waves in Horndeski theory. Besides the familiar plus and cross polarizations in Einstein’s General Relativity, there is one more polarization ...state which is the mixture of the transverse breathing and longitudinal polarizations. The additional mode is excited by the massive scalar field. In the massless limit, the longitudinal polarization disappears, while the breathing one persists. The upper bound on the graviton mass severely constrains the amplitude of the longitudinal polarization, which makes its detection highly unlikely by the ground-based or space-borne interferometers in the near future. However, pulsar timing arrays might be able to detect the polarization excited by the massive scalar field. Since additional polarization states appear in alternative theories of gravity, the measurement of the polarizations of gravitational waves can be used to probe the nature of gravity. In addition to the plus and cross states, the detection of the breathing polarization means that gravitation is mediated by massless spin 2 and spin 0 fields, and the detection of both the breathing and longitudinal states means that gravitation is propagated by the massless spin 2 and massive spin 0 fields.
Cobalt phosphides have been used as promising electrocatalysts for catalyzing the hydrogen evolution reaction (HER) in acidic aqueous solutions. In order to further explore the influence of phase ...structure and support effect on the catalytic activity for HER, herein, a series of cobalt phosphide-based electrocatalysts, including Co 2 P, CoP, Co 2 P/CNTs, CoP/CNTs, Co 2 P/NCNTs and CoP/NCNTs, were synthesized successfully via a facile thermal decomposition approach. The crystalline phase can be controlled by changing the phosphide source species. When the phosphide source was trioctylphosphine, CoP-based catalysts were obtained. However, Co 2 P-based catalysts can be obtained by using triphenylphosphine as the phosphide source. Then the phase catalytic activity and stability of the as-synthesized cobalt phosphide-based catalysts for hydrogen evolution were compared. The results show that the catalytic activity followed the order CoP/NCNTs > Co 2 P/NCNTs > CoP/CNTs > Co 2 P/CNTs > CoP > Co 2 P, which can be attributed to the different atomic ratios of Co to P, the strong interaction between cobalt phosphide and carbon species and the doping of N atoms into CNTs. Our studies indicate that the HER catalytic efficiency of transition metal phosphide catalysts can be improved significantly by adjusting active phase and carbon species structures.
Functional organic field‐effect transistors (OFETs) have attracted increasing attention in the past few years due to their wide variety of potential applications. Research on functional OFETs ...underpins future advances in organic electronics. In this review, different types of functional OFETs including organic phototransistors, organic memory FETs, organic light emitting FETs, sensors based on OFETs and other functional OFETs are introduced. In order to provide a comprehensive overview of this field, the history, current status of research, main challenges and prospects for functional OFETs are all discussed
Functional organic field‐effect transistors (OFETs) have attracted increasing attention due to their abilities in photoswitching, light detection, light emission, signal storage, sensing, and other areas and have many potential commercial applications. This review focuses on functional OFETs including organic phototransistors, organic non‐volatile memory FETs, organic light emitting FETs, sensors based on OFETs and other functional OFETs.
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