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Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 Ω /cm were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. [ABSTRACT FROM AUTHOR]

A simple patterning process to prepare conducting circuits in the atmosphere with the irradiation of laser and complex Cu nano-colloid was demonstrated. Stable Cu nano-colloids with a particle size of less than 10 nm were produced by an electrical wire explosion process in anhydrous ethanol. Uniform Cu film without cracks was prepared by using a Cu nano-colloid with copper(II) nitrate trihydrate. Various kinds of conductive Cu patterns on a flexible substrate were prepared by laser irradiation in air. The Cu pattern on a flexible polyimide substrate showed about 40 Ω/square of electrical sheet resistance. [ABSTRACT FROM AUTHOR]

Air-stable Cu nanoparticles (NPs) with an average diameter of 6.5 nm were synthesized under ambient conditions using polyvinylpyrrolidone and cetyltrimethylammonium bromide as a mixed capping agent, for preparing nano-Cu ink applicable for direct writing on photo paper using a roller pen. The size, morphology, and air-stability of the Cu NPs were characterized by TEM, SEM, XRD, etc. The mixed capping agent was effective in reducing the aggregation, size of the Cu NPs and improving their air-stability. The reduced size and enhanced air-stability of the Cu NPs resulted in an improved particle density upon sintering, which was mainly responsible for the increased conductivity of the Cu patterns. The resistivity of Cu patterns sintered at 160 °C for 2 h was 11 ± 0.8 μΩ cm, 6.40 times the bulk resistivity. A sample RFID antenna and a decorative logo were successfully made and the Cu patterns or lines exhibited excellent integrity and good conductivity, which were experimentally tested. [ABSTRACT FROM AUTHOR]

An unusual kind of transparent and high-efficiency organic silver conductive ink (OSC ink) was synthesized with silver acetate as silver carrier, ethanolamine as additive, and different kinds of aldehyde-based materials as reduction agents and was characterized by using a thermogravimetric analyzer, X-ray diffraction, a scanning electron microscope, and a four-point probe. The results show that different reduction agents all have an important influence on the conductive properties of the ink through a series of complex chemical reactions, and especially when formic acid or dimethylformamide was used as the reduction agent and sintered at 120°C for 30 s, the resistivity can be lowered to 6 to 9 µΩ⋅cm. Furthermore, formula mechanism, conductive properties, temperature, and dynamic fatigue properties were investigated systematically, and the feasibility of the OSC ink was also verified through the preparation of an antenna pattern. [ABSTRACT FROM AUTHOR]

Pulsed electrohydrodynamic printing (EHDP) is used to fabricate conductive silver patterns with micrometer resolution. The silver ink pendant experiences swelling, pulsation, and ejection under an applied pulse voltage of 20 Hz. The droplet deposition frequency is equal to the applied voltage frequency so that the EHDP can deposit silver ink on demand. A low applied voltage favors uniform and non-scattering silver patterns while a high applied voltage results in ink scattering. Discrete droplets with 45-55 μm in diameter and continuous tracks with 60 μm in width are generated by using a 110-μm-cailber nozzle. The feature size of deposited patterns is about half of the nozzle caliber, and a finer resolution can be achieved with the introduction of smaller nozzle calibers. Furthermore, the appropriate curing condition is investigated for sufficient combustion of ink solvent. The minimum resistivity of 3.3 μΩ cm is demonstrated for a continuous track cured at 200°C for 10 min. Eventually, several passive electrical components, such as coated resistors, interdigitated capacitors (6 pF), and spiral inductors (0.6 μH), are successfully fabricated. [ABSTRACT FROM AUTHOR]