Interface-Engineered High-Performance Flexible Thermoelectric Films for Self-Powered Health Monitoring.

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Flexible thermoelectric (TE) materials are crucial for self-powered wearable electronics but face challenges in balancing electrical/thermal transport with flexibility.
• Current designs often lack application-driven co-design between materials and devices, limiting practical implementation.

Purpose of the Study:

• To develop a flexible TE material with enhanced performance by incorporating an insulating polymer.
• To investigate the multifunctional interfacial effects of polyvinylpyrrolidone (PVP) on a silver selenide (Ag2Se)-based matrix for improved carrier-phonon decoupling.

Main Methods:

• Incorporation of polyvinylpyrrolidone (PVP), an insulating polymer, into a flexible Ag2Se-based thermoelectric matrix.
• Characterization of the resulting flexible TE film's electrical and thermal transport properties.
• Assembly and testing of a flexible TE generator and a thermoelectric-powered healthcare monitoring device (TE-cup).

Main Results:

• Achieved a record-high power factor of 3328 ± 332 µW m⁻¹ K⁻² and a figure of merit (ZT) of 1.1 at 341 K.
• The addition of PVP promoted coherent grain boundaries and mitigated Fermi-level pinning, enhancing TE performance.
• The flexible TE generator demonstrated a normalized power density of 81 W m⁻² under a 35 K temperature gradient.

Conclusions:

• Non-conductive polymers can play a beneficial role in TE nanocomposites, contrary to previous assumptions.
• The study presents an effective strategy for manipulating material structure to enhance thermoelectric properties.
• A self-sustained platform for next-generation healthcare monitoring, integrating physiological sensing and energy harvesting, was successfully demonstrated.