Organic semiconductor gas sensor is one of the promising candidates of room temperature operated gas sensors with high selectivity. However, for a long time the performance of organic semiconductor ...sensors, especially for the detection of oxidizing gases, is far behind that of the traditional metal oxide gas sensors. Although intensive attempts have been made to address the problem, the performance and the understanding of the sensing mechanism are still far from sufficient. Herein, an ultrasensitive organic semiconductor NO2 sensor based on 6,13‐bis(triisopropylsilylethynyl)pentacene (TIPS‐petacene) is reported. The device achieves a sensitivity over 1000%/ppm and fast response/recovery, together with a low limit of detection (LOD) of 20 ppb, all of which reach the level of metal oxide sensors. After a comprehensive analysis on the morphology and electrical properties of the organic films, it is revealed that the ultrahigh performance is largely related to the film charge transport ability, which was less concerned in the studies previously. And the combination of efficient charge transport and low original charge carrier concentration is demonstrated to be an effective access to obtain high performance organic semiconductor gas sensors.
An ultrasensitive organic semiconductor NO2 sensor based on crystalline 6,13‐bis(triisopropylsilylethynyl)pentacene films is achieved with a sensitivity over 1000% ppm–1 and fast response/recovery within 200 s/400 s. The relationship between sensor performance and film charge transport is studied. The low original carrier concentration and efficient charge transport are demonstrated to be key factors for the ultrahigh performance.
Current research activities on colloidal lithography, a highly efficient technology for fabricating large-area patterned functional nanostructures are summarized, including three aspects: i) ...self-assembly of colloidal spheres and their modifications; ii) lithographic patterning methods and pattern transfer; iii) promising applications, especially in the optical and photonic-related fields.
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•The review presents recent progress of colloidal lithography ranging from surface patterning to functional applications.•It contains self-assembly and modifications of colloids, fabrication and applications of patterned nanostructures.•Modifications of colloids have been reviewed including morphological change and functionalized decoration.•Lithographic patterning methods, including deposition and patterning of functional materials, pattern transfer, are presented.•The optical and photonic related applications, including antireflection, LSPR-based sensors, SERS and SALDI-MS, in particular.
This article presents a comprehensive review about the current research activities on colloidal lithography, a highly efficient technology for fabricating large-area patterned functional nanostructures. Three aspects are elaborated: i) self-assembly of monolayer of colloidal crystals (MCCs) and their modifications; ii) lithographic patterning methods, including deposition and patterning of functional materials and pattern transfer onto the underlying substrates; iii) promising applications, especially in the optical and photonic-related fields in the past several years. Finally, perspectives on the current challenges and future trends in this area are given. The present review intends to inspire more ingenious designs and exciting research in colloidal lithography for advanced nanofabrication.
Recent advances in flexible and stretchable electronics (FSE), a technology diverging from the conventional rigid silicon technology, have stimulated fundamental scientific and technological research ...efforts. FSE aims at enabling disruptive applications such as flexible displays, wearable sensors, printed RFID tags on packaging, electronics on skin/organs, and Internet-of-things as well as possibly reducing the cost of electronic device fabrication. Thus, the key materials components of electronics, the semiconductor, the dielectric, and the conductor as well as the passive (substrate, planarization, passivation, and encapsulation layers) must exhibit electrical performance and mechanical properties compatible with FSE components and products. In this review, we summarize and analyze recent advances in materials concepts as well as in thin-film fabrication techniques for high-k (or high-capacitance) gate dielectrics when integrated with FSE-compatible semiconductors such as organics, metal oxides, quantum dot arrays, carbon nanotubes, graphene, and other 2D semiconductors. Since thin-film transistors (TFTs) are the key enablers of FSE devices, we discuss TFT structures and operation mechanisms after a discussion on the needs and general requirements of gate dielectrics. Also, the advantages of high-k dielectrics over low-k ones in TFT applications were elaborated. Next, after presenting the design and properties of high-k polymers and inorganic, electrolyte, and hybrid dielectric families, we focus on the most important fabrication methodologies for their deposition as TFT gate dielectric thin films. Furthermore, we provide a detailed summary of recent progress in performance of FSE TFTs based on these high-k dielectrics, focusing primarily on emerging semiconductor types. Finally, we conclude with an outlook and challenges section.
The successful synthesis of stacking graphdiynes has stimulated numerous fascinating applications. However, it still remains challenging to prepare atomically precise 2D graphdiyne and other ...graphyne‐based structures. The development of on‐surface synthesis has contributed to many secondary graphyne‐based structures that are directive in fabricating extended graphyne networks. Herein, the recent progress concerning on‐surface synthesis of graphyne‐based nanostructures, especially atomically precise graphdiyne nanowires, is summarized.
On‐surface construction of acetylenic or diacetylenic linkages is a promising strategy to prepare low‐dimensional graphyne‐based nanostructures. The methodologies to fabricate 1D graphyne (graphdiyne) nanowires and their functionalized derivatives are presented to illustrate how on‐surface synthesis may contribute to 2D graphyne‐related structures.
Gold–organic hybrids can be prepared on gold substrates by on‐surface dehalogenation of molecular precursors with multiple halogen substituents. Various contact geometries of covalent arylAu bonds ...are achieved by changing the halogen substituents in the bay or peri regions. Scanning tunneling microscopy/spectroscopy (STM/STS) investigations allow a better understanding of the structure/property relationships in various gold–aryl contacts. Recent progress on the synthesis, large‐scale alignment, and STS measurement of gold–organic hybrids is described, ending with an emphasis on potential future applications, e.g., as precursors (intermediates) for the synthesis of graphene nanoribbons (GNRs) on insulating surfaces, and as a model system to investigate the role of covalent arylAu bonds in electron transport through gold–GNR contacts.
Gold–organic hybrids with various arylAu bonding geometries can be prepared on gold substrates through on‐surface dehalogenation of molecular precursors with multiple halogen substituents. Recent progress made in the synthesis, large‐scale alignment and scanning tunneling spectroscopy of gold–organic hybrids is highlighted.
This review focuses on polymer field-effect transistor (PFET) based gas sensor with polymer as the sensing layer, which interacts with gas analyte and thus induces the change of source-drain current ...(Δ
). Dependent on the sensing layer which can be semiconducting polymer, dielectric layer or conducting polymer gate, the PFET sensors can be subdivided into three types. For each type of sensor, we present the molecular structure of sensing polymer, the gas analyte and the sensing performance. Most importantly, we summarize various analyte-polymer interactions, which help to understand the sensing mechanism in the PFET sensors and can provide possible approaches for the sensor fabrication in the future.
Integrating covalent organic frameworks (COFs) with other functional materials is a useful route to enhancing their performances and extending their applications. We report herein a simple ...encapsulation method for incorporating catalytically active Au nanoparticles with different sizes, shapes, and contents in a two-dimensional (2D) COF material constructed by condensing 1,3,5-tris(4-aminophenyl)benzene (TAPB) with 2,5-dimethoxyterephthaldehyde (DMTP). The encapsulation is assisted by the surface functionalization of Au nanoparticles with polyvinylpyrrolidone (PVP) and follows a mechanism based on the adsorption of nanoparticles onto surfaces of the initially formed polymeric precursor of COF. The incorporation of nanoparticles does not alter obviously the crystallinity, thermal stability, and pore structures of the framework matrices. The obtained COF composites with embedded but accessible Au nanoparticles possess large surface areas and highly open mesopores and display recyclable catalytic performance for reduction of 4-nitrophenol, which cannot be catalyzed by the pure COF material, with activities relevant to contents and geometric structures of the incorporated nanoparticles.
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.
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