Related Articles

3D printing of micro-nano devices and their applications

In recent years, the utilization of 3D printing technology in micro and nano device manufacturing has garnered significant attention. Advancements in 3D printing have enabled achieving sub-micron level precision. Unlike conventional micro-machining techniques, 3D printing offers versatility in material selection, such as polymers. 3D printing technology has been gradually applied to the general field of microelectronic devices such as sensors, actuators and flexible electronics due to its adaptability and efficacy in microgeometric design and manufacturing processes. Furthermore, 3D printing technology has also been instrumental in the fabrication of microfluidic devices, both through direct and indirect processes. This paper provides an overview of the evolving landscape of 3D printing technology, delineating the essential materials and processes involved in fabricating microelectronic and microfluidic devices in recent times. Additionally, it synthesizes the diverse applications of these technologies across different domains.

Spin injection in graphene using ferromagnetic van der Waals contacts of indium and cobalt

Graphene-based spintronic devices require efficient spin injection, and dielectric tunnel barriers are typically used to facilitate spin injection. However, the direct growth of ultrathin dielectrics on two-dimensional surfaces is challenging and unreliable. Here we report spin injection in graphene lateral spin valves using ferromagnetic van der Waals contacts of indium and cobalt (In–Co), and without the deposition of dielectric tunnel barriers. With this approach, we obtain magnetoresistance values of 1.5% ± 0.5% (spin signal around 50 Ω), which is comparable to state-of-the-art graphene lateral spin valves with oxide tunnel barriers, with a working device yield of more than 70%. By contrast, lateral spin valves with non-van der Waals contacts containing only cobalt are inefficient and exhibit, at best, a magnetoresistance of around 0.2% (spin signal around 3 Ω). The contact resistance of our ferromagnetic indium–cobalt van der Waals contacts is 2–5 kΩ, which makes them compatible with complementary metal–oxide–semiconductor devices.

Flash Joule heating for synthesis, upcycling and remediation

Electric heating methods are being developed and used to electrify industrial applications and lower their carbon emissions. Direct Joule resistive heating is an energy-efficient electric heating technique that has been widely tested at the bench scale and could replace some energy-intensive and carbon-intensive processes. In this Review, we discuss the use of flash Joule heating (FJH) in processes that are traditionally energy-intensive or carbon-intensive. FJH uses pulse current discharge to rapidly heat materials directly to a desired temperature; it has high-temperature capabilities (>3,000 °C), fast heating and cooling rates (>102 °C s−1), short duration (milliseconds to seconds) and high energy efficiency (~100%). Carbon materials and metastable inorganic materials can be synthesized using FJH from virgin materials and waste feedstocks. FJH is also applied in resource recovery (such as from e-waste) and waste upcycling. An emerging application is in environmental remediation, where FJH can be used to rapidly degrade perfluoroalkyl and polyfluoroalkyl substances and to remove or immobilize heavy metals in soil and solid wastes. Life-cycle and technoeconomic analyses suggest that FJH can reduce energy consumption and carbon emissions and be cost-efficient compared with existing methods. Bringing FJH to industrially relevant scales requires further equipment and engineering development.

A network analysis of postpartum depression and mother-to-infant bonding shows common and unique symptom-level connections across three postpartum periods

Postpartum depression and mother-to-infant bonding difficulties (MIBD), two issues crucial to maternal and infant mental health, often coexist and affect each other. Our study aims to dissect their complex relationship through a graphical LASSO network analysis of individual symptoms in 5594 Japanese postpartum women, whose geographical distribution was nationally representative. We identified ‘fear’, ‘enjoyment’, ‘overwhelm’, and ‘insomnia’ as common bridge symptoms linking postpartum depression and MIBD across three distinct postpartum periods. Moreover, ‘self-harm’ emerged as a bridge symptom in the first 6 months and the 7–12 month period, while ‘laugh’ was a bridge symptom in the first 6 months and the 13–24 month period. Notably, ‘self-blame’ was identified as a unique bridge symptom specific to the 13–24 month period. Our analysis highlights the complexities of symptom connectivity across postpartum stages and underscores the critical need for interventions that address both common and stage-specific bridge symptoms to effectively support maternal mental health and strengthen mother-to-infant bonding.

Promises and challenges of indoor photovoltaics

Indoor photovoltaics (IPVs) harvest ambient light to produce electricity and can cleanly power the rapidly growing number of Internet-of-Things (IoT) sensors. The surge in IPV development, with new proposed materials, devices and products, creates the need to critically evaluate how IPV devices have advanced and to assess their prospects. In this Review, we analyse the status, challenges and opportunities of established and emerging IPV technologies, including metal-halide perovskite, organic photovoltaics, dye-sensitized solar cell and perovskite-inspired materials. Many emerging low-toxicity semiconductor materials could reach IPV efficiencies of up to 50%, but carrier localization and defect trapping hinder their performance. Wide adoption of standardized performance assessment methods is essential, and further harmonization is needed for stress tests, qualification standards and energy rating assessments. For seamless IPV integration in IoT devices, series-connected cell modules and appropriate power management hardware are crucial to maximize energy extraction. IPV device stability, technology upscaling and cost-effective integration in IoT sensors must be further developed but balanced with sustainability across the entire value chain.

Responses

Your email address will not be published. Required fields are marked *