Microfluidic devices fabricated via soft lithography have demonstrated compelling applications such as lab-on-a-chip diagnostics, DNA microarrays, and cell-based assays. These technologies could be further developed by directly integrating microfluidics with electronic sensors and curvilinear substrates as well as improved automation for higher throughput. Current additive manufacturing methods, such as stereolithography and multi-jet printing, tend to contaminate substrates with uncured resins or supporting materials during printing. Here, we present a printing methodology based on precisely extruding viscoelastic inks into self-supporting microchannels and chambers without requiring sacrificial materials. We demonstrate that, in the submillimeter regime, the yield strength of the as-extruded silicone ink is sufficient to prevent creep within a certain angular range. Printing toolpaths are specifically designed to realize leakage-free connections between channels and chambers, T-shaped intersections, and overlapping channels. The self-supporting microfluidic structures enable the automatable fabrication of multifunctional devices, including multimaterial mixers, microfluidic-integrated sensors, automation components, and 3D microfluidics.

Black arsenic (BAs) is an elemental van der Waals semiconductor that is promising for a wide range of electronic and photonic applications. The narrow bandgap and symmetric band structure suggest that ambipolar (both n- and p-type) transport should be observable, however, only p-type transport has been experimentally studied to date. Here, we demonstrate and characterize ambipolar transport in exfoliated BAs field effect transistors. In the thickest flakes (∼ 80 nm), maximum currents, Imax, up to 60 μA μm−1 and 90 μA μm−1are achieved for hole and electron conduction, respectively. Room-temperature hole (electron) mobilities up to 150 cm2 V−1 s−1 (175 cm2 V−1 s−1) were obtained, with temperature-dependence consistent with a phonon-scattering mechanism. The Schottky barrier height for Ni contacts to BAs was also extracted from the temperature-dependent measurements. Imax for both n- and p-type conductivity was found to decrease with reduced thickness, while the ratio of Imax to the minimum current, Imin, increased. In the thinnest flakes (∼ 1.5 nm), only p-type conductivity was observed with the lowest value of Imin = 400 fA μm−1. Imax/Imin ratios as high as 5 × 105 (5 × 102) were obtained, for p- (n-channel) devices. Finally, the ambipolarity was used to demonstrate a complementary logic inverter and a frequency doubling circuit.

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Rivian, an American maker of electric pickups, went public on The Nasdaq on November 10, 2021, pricing at $78 and raising $12 billion. The IPO rose 29.14% on its first day, with a market value of more than $80 billion, making it the world's seventh largest automaker. A week later it overtook Volkswagen to become the world's third-largest carmaker, with a market capitalisation of $151.9 billion. For a car company that has not yet begun to deliver on a large scale, this is undoubtedly an exaggeration. Based on the listing experience of Rivian, this paper aims to expand and analyze how electric vehicles have become the general trend, and what advantages and disadvantages they have compared with traditional fuel vehicles. And Rivian, as the electric car company most likely to replicate Tesla's legendary experience, has an advantage over other companies, and what its future should be.

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