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The value of two-dimensional (2D) materials in printed electronics has been gradually explored, and the rheological properties of 2D material dispersions are very different for various printing technologies. Understanding the rheological properties of 2D material dispersions plays a vital role in selecting the optimal manufacturing technology. Inkjet printing is suitable for small nanosheet sizes and low solution viscosity, and it has a significant advantage in developing nanosheet inks because of its masklessness, high efficiency, and high precision. In this work, we selected 2D Ti0.8Co0.2O2 nanosheets, which can be synthesized in large quantities by the liquid phase exfoliation technique; investigated the effects of nanosheet particle size, solution concentration on the rheological properties of the dispersion; and obtained the optimal printing processing method of the dispersion as inkjet printing. The ultrathin Ti0.8Co0.2O2 nanosheet films were prepared by inkjet printing, and their magnetic characteristics were compared with those of Ti0.8Co0.2O2 powder. The films prepared by inkjet printing exhibited long-range ordering, maintaining the nanosheet powders' paramagnetic characteristics. Our work underscored the potential of inkjet printing as a promising method for fabricating precisely controlled thin films using 2D materials, with applications spanning electronics, sensors, and catalysis. [ABSTRACT FROM AUTHOR]

All-printed microcapacitors made of high- k perovskite nanosheets (i.e., Ca 2 Nb 3 O 10 and Ca 2 NaNb 4 O 13) with different electrodes are prepared by inkjet printing. The dielectric constant of the microcapacirors with graphene electrode is nearly-four times higher than those with silver electrodes. These inkjet-printed microcapacitors exhibited large capacitance density of 150 nF/cm2, high dielectric constant up to 200, excellent flexibility, and thermal stability up to 200 ℃. [Display omitted] Chemically exfoliated nanosheets have exhibited great potential for applications in various electronic devices. Solution-based processing strategies such as inkjet printing provide a low-cost, environmentally friendly, and scalable route for the fabrication of flexible devices based on functional inks of two-dimensional nanosheets. In this study, chemically exfoliated high- k perovskite nanosheets (i.e., Ca 2 Nb 3 O 10 and Ca 2 NaNb 4 O 13) are well dispersed in appropriate solvents to prepare printable inks, and then, a series of microcapacitors with Ag and graphene electrodes are printed. The resulting microcapacitors, Ag/Ca 2 Nb 3 O 10 /Ag, graphene/Ca 2 Nb 3 O 10 /graphene, and graphene/Ca 2 NaNb 4 O 13 /graphene, demonstrate high capacitance densities of 20, 80, and 150 nF/cm2 and high dielectric constants of 26, 110, and 200, respectively. Such dielectric enhancement in the microcapacitors with graphene electrodes is possibly attributed to the dielectric/graphene interface. In addition, these microcapacitors also exhibit good insulating performance with a moderate electrical breakdown strength of approximately 1 MV/cm, excellent flexibility, and thermal stability up to 200 ℃. This work demonstrates the potential of high- k perovskite nanosheets for additive manufacturing of flexible high-performance dielectric capacitors. [ABSTRACT FROM AUTHOR]

Dielectric capacitors are an essential passive component widely used in integrated circuits. Recently, inkjet printing of 2D nanosheets into highly insulating layers has been developed for capacitor applications. However, the relatively low dielectric constant inherently associated with 2D nanosheets will hinder the rational design of high‐performance capacitor devices. In this work, the inks of high‐k Ca2NaNb4O13 perovskite nanosheets are formulated, and all‐printed dielectric capacitor consisting of Ca2NaNb4O13 films with commercial Ag electrodes is demonstrated. An average areal capacitance of ≈21 nF cm−2, together with low current density (<10−7 A cm−2) and low dielectric loss (≈2%), is achieved for the dielectric layer with thickness of ≈2 µm. The research shows that high‐k perovskite nanosheets have a great potential for applications in ink‐based additive manufacturing of flexible electronic devices. [ABSTRACT FROM AUTHOR]

Abstract: A high quality anodic aluminum oxide (AAO) template with ordered apertures about 50–80nm was fabricated by anodizing aluminum in electrolytes through a two-step method, and silver nanowires with diameters from 40nm to 70nm were prepared on this AAO template by magnetron sputtering. On the glass covered with silver nanowires, high quality surface enhanced Raman scattering (SERS) spectra of sudan II (C18H16N2O) with enhancement factors of 105 were obtained. And comparison of SERS spectra on silver nanowires with the SERS spectra of silver colloids indicates that main enhanced mode is lightning rod effect of nanorods on the Sudan II/silver nanowires system. [Copyright &y& Elsevier]

Abstract: Gold nanowires array with diameter from 90 to 110nm was prepared on AAO template by laser molecular beam epitaxy (LMBE), and surface-enhanced Raman scattering (SERS) spectrum of probe molecules nicotinic acid (NA) were recorded on the gold nanowires array. The Raman and SERS spectrum of NA using DFT-B3PW91 with lanl2dz based on two models were calculated, and compared with the experimental results. It was found the calculated frequencies were in good agreement with experimental values, which indicates that there are two enhanced mechanism which electromagnetic enhancement and charge transfer enhancement, on the gold nanowires array regarding SERS effect. [Copyright &y& Elsevier]

Abstract: Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications. [Copyright &y& Elsevier]