Direct Laser Writing (DLW) has been increasingly selected as a microfabrication route for efficient, cost‐effective, high‐resolution material synthesis and conversion. Concurrently, lasers participate in the patterning and assembly of functional geometries in several fields of application, of which electronics stand out. In this review, recent advances and strategies based on DLW for electronics microfabrication are surveyed and outlined, based on laser material growth strategies. First, the main DLW parameters influencing material synthesis and transformation mechanisms are summarized, aimed at selective, tailored writing of conductive and semiconducting materials. Additive and transformative DLW processing mechanisms are discussed, to open space to explore several categories of materials directly synthesized or transformed for electronics microfabrication. These include metallic conductors, metal oxides, transition metal chalcogenides and carbides, laser‐induced graphene, and their mixtures. By accessing a wide range of material types, DLW‐based electronic applications are explored, including processing components, energy harvesting and storage, sensing, and bioelectronics. The expanded capability of lasers to participate in multiple fabrication steps at different implementation levels, from material engineering to device processing, indicates their future applicability to next‐generation electronics, where more accessible, green microfabrication approaches integrate lasers as comprehensive tools.

Since the discovery of laser-induced graphene (LIG), significant advances have been made to obtain green LIG (gLIG) from abundant, eco-friendly, natural, and organic renewable bio-based carbon sources. Recently, some sustainable and cost-effective electronic devices have been designed with gLIG, resulting in diverse solutions to the environmental impact caused by electronic waste (e-waste). However, there are still several challenges that must be addressed regarding the widespread market implementation of gLIG-based products, from synthesis to practical applications. In this review, we focus on sustainable precursor sources, their conversion mechanisms, physical and chemical properties and applications, along with the challenges related to its implementation, showing the future opportunities and perspectives related to this promising new material. Various systems based on gLIG for energy storage, electrocatalysis, water treatment, and sensors have been reported in the literature. Additionally, gLIG has been proposed for ink formulation or incorporation into polymer matrices, to further expand its use to non-carbon-based substrates or applications for which pristine LIG cannot be directly used. In this way, it is possible to apply gLIG on diverse substrates, aiming at emerging wearable and edible electronics. Thus, this review will bring an overview of gLIG developments, in accordance with the European Green Deal, the United Nations Sustainable Development Goals and the new era of internet-of-things, which demands cost-effective electronic components based on the principles of energy efficiency and sustainable production methods.

Laser-induced graphene (LIG) is as a promising material for flexible microsupercapacitors (MSCs) due to its simple and cost-effective processing. However, LIG-MSC research and production has been centered on non-sustainable polymeric substrates, such as polyimide. In this work, it is presented a cost-effective, reproducible, and robust approach for the preparation of LIG structures via a one-step laser direct writing on chromatography paper. The developed strategy relies on soaking the paper in a 0.1 M sodium tetraborate solution (borax) prior to the laser processing. Borax acts as a fire-retardant agent, thus allowing the laser processing of sensitive substrates that other way would be easily destroyed under the high-energy beam. LIG on paper exhibiting low sheet resistance (30 Ω sq⁻¹) and improved electrode/electrolyte interface was obtained by the proposed method. When used as microsupercapacitor electrodes, this laser-induced graphene resulted in specific capacitances of 4.6 mF cm⁻² (0.015 mA cm⁻²). Furthermore, the devices exhibit excellent cycling stability (> 10,000 cycles at 0.5 mA cm⁻²) and good mechanical properties. By connecting the devices in series and parallel, it was also possible to control the voltage and energy delivered by the system. Thus, paper-based LIG-MSC can be used as energy storage devices for flexible, low-cost, and portable electronics. Additionally, due to their flexible design and architecture, they can be easily adapted to other circuits and applications with different power requirements. Graphical Abstract

The demand for smart, wearable devices has been dictating our daily life with the evolution of integrated miniaturized electronics. With technological innovations, comes the impactful human footprint left on the planet’s ecosystems. Therefore, it is necessary to explore renewable materials and sustainable methodologies for industrial processes. Here, an eco-friendly approach to producing flexible electrodes based on a single-step direct laser writing is reported. A 1.06 µm wavelength fiber laser was used for the first time to produce porous three-dimensional laser-induced graphene (LIG) on an agglomerated cork substrates. The obtained material exhibits the typical Raman spectra, along with an exceptionally low sheet resistance between 7.5 and 10 ohm sq⁻¹. LIG on cork high electrical conductivity and the friendliness of the used production method, makes it an interesting material for future technological applications. To show its applicability, the production of planar micro-supercapacitors was demonstrated, as a proof of concept. Electrochemical performance studies demonstrate that LIG interdigitated electrodes, using PVA-H₂SO₄ electrolyte, achieve an area capacitance of 1.35 mF cm⁻² (103.63 mF cm⁻³) at 5 mV s⁻¹ and 1.43 mF cm⁻² (109.62 mF cm⁻³) at 0.1 mA cm⁻². In addition, devices tested under bending conditions exhibit a capacitance of 2.20 mF cm⁻² (169.22 mF cm⁻³) at 0.1 mA cm⁻². Here, showing that these electrodes can be implemented in energy storage devices, also successfully demonstrating LIG promising application on innovative, green, and self-sustaining platforms.