Speaker
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The rapid expansion of electronic technologies has intensified concerns regarding electronic waste, resource depletion, and the environmental impact of manufacturing processes. These issues are particularly critical for emerging classes of ultra-thin, flexible, and disposable electronics, where short device lifetimes are often paired with fabrication routes that remain energy-intensive, chemically aggressive, and poorly recyclable. Conventional microfabrication techniques largely inherited from silicon-based electronics rely on complex photolithographic workflows, hazardous solvents and etchants, and single-use substrates, thus limiting their alignment with the principles of green electronics, circularity, and sustainable manufacturing.
To address these challenges, the field of sustainable electronics is increasingly exploring alternative fabrication paradigms that minimize material consumption, reduce chemical waste, and enable substrate reuse. Transfer-based approaches offer an attractive strategy by decoupling device fabrication from the final application, thereby expanding the choice of substrates and protecting fragile or unconventional materials [1]. These techniques rely on conventional fabrication, such as physical vapor deposition, involving a donor substrate. In a second step, the functional electronics elements are detached and transferred to the desired substrate. However, most existing transfer methods rely on sacrificial layers between the donor substrate and the functional elements, inherently introducing additional materials, solvents, and processing steps that increase waste, cost, and environmental burden. Although sacrificial layer materials and compatible solvents have been developed to enable bio- and environmentally friendly transfer methods [2,3], the sacrificial layers always involve an extra limiting step and material losses, which increase the cost and are time-consuming.
In this contribution, we present a sacrificial-layer-free transfer method inspired by wet-processing and microfluidic principles, exploiting interfacial energy and wetting contrast to enable the spontaneous release of ultra-thin functional layers. Functional elements are patterned directly onto superhydrophilic donor substrates (contact angle <10°) using shadow-mask-assisted sputtering. Upon immersion in water, the interfacial energy mismatch induces autonomous delamination of the functional layer, which floats on the water surface and can be transferred onto a wide range of target substrates without chemical etchants, adhesives, or mechanical force.
Importantly, the donor substrate remains chemically unaltered, retains its hydrophilic properties, and can be immediately reused, enabling zero material loss and full process recyclability. The method is compatible with diverse functional materials, including dielectric, metallic conductors (Cu, Ag, Ti), and semiconductors, enabling the transfer of multilayer device architectures. We have proven the full transfer of temperature and gas sensors, using both thermistors and resistive sensors. Notably, the method presented is compatible with exotic substrates, such as stretchable polymers, delicate natural materials (including insect wings or bird feathers), and complex 3D substrates relevant to flexible electronics and microfluidic platforms. By eliminating sacrificial materials and reducing chemical and energy inputs, this approach provides a scalable route toward low-impact, circular microfabrication and represents a step forward in the development of truly green electronic technologies.
[1] Salvatore, G. A., et al. Nat. Commun. 5.1 (2014): 2982.
[2] Oliveira, H. D. S., et al. Adv. Electron. Mater. 9.9 (2023): 2201281.
[3] Bezsmertna, O., et al. Adv. Funct. Mater. (2025): 2502947.