Nano-Solder Enabled E-Textile Sensors for Hazardous Gas Detection

Conventional solders such as Sn/Pb or lead-free solders such as SAC alloys provide reliable metallurgical bonding for electronic components or chips on rigid substrates; however, their typical processing temperatures around 200 °C or higher exceed the thermal stability of most cotton or polymer-based fabrics, undesirable for direct use in soldering wearable electronic textiles (E-textiles) and their related applications. Current strategies for incorporating functional materials onto fabrics—primarily chemical conjugation or physical embedding via sonication—lack stable, electrically robust interfaces and do not leverage joining science principles and technologies. To date, limited approach has been implemented in micro- or nano-scale soldering as a means of forming functional electrical interconnections on textile substrates.

This work introduces a low-melting-temperature nano‑solder joining method for enabling graphene-based e-textile gas sensors on NyCo fabric. Using Sn–In micro/nano‑joining at electrode interfaces, printed graphene/carboxylated graphene oxide (GO) sensing films are metallurgically bonded and mechanically stabilized on the fabric at relatively low processing temperatures, without exceeding substrate thermal limits. Room‑temperature exposures to various analytes, such as ammonia, acetic acid, and selective VOCs (Volatile Organic Compounds), exhibit reproducible signal responses, reduced baseline drift relative to non-joined films, and rapid response characteristics. By centering the device architecture around a micro/nano‑joining-enabled electrical interface, this work offers a practical pathway toward textile-integrated sensors with enhanced stability and long-term reliability. Future studies will investigate cross-environment durability and analyte-specific selectivity to support deployment in complex vapor mixtures.