Ultra-sensitive and high-resolution flexible thermoelectric sensor enabled by p-n heterojunction array structure

Abstract

Flexible, self-powered thermoelectric temperature sensors with high reliability are increasingly recognized as essential components in tactile perception, wearable technologies, and medical monitoring. To fulfill the performance requirements of these applications—specifically, achieving high Seebeck coefficients and superior resolution—traditional fabrication strategies typically rely on intricate molecular engineering, microscale structural optimization, or macroscale topological design. However, these approaches often involve complex manufacturing processes and elevated production costs, constraining large-scale deployment. Here, we propose a simple multilayer assembly approach that harnesses a self-permeation effect to enable the facile and cost-effective fabrication of flexible thermoelectric sensors with significantly improved sensitivity and resolution. By inducing intensive p-n heterojunctions through self-permeation and leveraging phonon scattering at multilayer-structured interfaces, the obtained sensor exhibits an unprecedented sensitivity of 1,203.6 μV K⁻¹ and an ultimate temperature difference detection capability of 0.001 K, showcasing great potential for applications in three-dimensional environmental monitoring and bionic robotic tactile sensing.