Printable Thermoelectric Ink for Self-Healing, Thermally Responsive Soft Devices

Emerging technologies such as wearable electronics and soft robotics require thermoelectric materials that can be digitally fabricated into application-specific geometries while maintaining mechanical compliance. However, most existing thermoelectric inks rely on high-temperature sintering or rigid inorganic binders, limiting manufacturing versatility and flexibility. Here, we present a printable thermoelectric ink composed of microscale bismuth telluride particles dispersed within a viscoelastic styrene-isoprene-styrene polymer matrix, enabling direct ink writing of soft thermoelectric architectures under ambient, room temperature conditions. The ink combines tunable viscoelasticity with electrostatically driven particle and polymer interactions to form stable conductive pathways while preserving printing fidelity without post-sintering. The printed structures retain thermoelectric performance under mechanical deformation and exhibit solvent-assisted self-healing and biocompatibility. By integrating rheological tunability, mechanical flexibility, thermoelectric energy conversion, and thermal sensing capabilities, the printable ink provides a versatile platform for low temperature, programmable manufacturing of soft thermoelectric devices, offering new opportunities for self powered electronic skins, adaptive robotic systems, and biointegrated electronics.