Morphology-engineered nanostructured silver- and antimony-telluride films for flexible thermoelectric generators

TL;DR

This study develops flexible thermoelectric films from nanostructured silver and antimony-telluride, enhanced by morphology engineering and doping, achieving significantly improved power output for wearable energy harvesting.

Contribution

It introduces a novel synthesis and doping strategy for nanostructured thermoelectric films, leading to higher power factors and device performance in flexible thermoelectric generators.

Findings

Up to 8-fold increase in power factor with S doping.

Maximum power output of 120 nW at ΔT 30°C.

Device resistance increases under mechanical bending.

Abstract

Harvesting low-grade heat to electricity is attractive for powering wearable electronic devices. Here, we demonstrate nW-scale thermoelectric power generation in devices from thin film assemblies of microwave-synthesized p-Sb2Te3 nanoplates and n-Ag2Te nanowires on polyvinylidene fluoride membranes. While microwave cycling is crucial for Ag2Te nanocrystal shaping, Sb2Te3 formation is sensitive to precursors and surfactant concentrations. Introducing S doping in Sb2Te3 in the 1 - 1.5 atomic percent range via thioglycolic acid during synthesis yields an up to eightfold higher power-factor, due to a fivefold increase in electrical conductivity and 25% increase in Seebeck coefficient. Our microfilm devices generate up to 33.6 mV from 5 deg C to 50 deg C thermal gradients, with 120 nW maximum power output at Delta T 30 deg C, which is sixtyfold higher than Sb2Te3 paper devices. Mechanical bending can increase device resistance by up to 125% due to diminished inter-nanostructure electronic transport. These findings provide insights for integrating synthesis, morphology engineering and device design for next-generation wearable thermoelectric systems.