Lightweight Flexible Biodegradable Thin-film Thermoelectric Module Based on Thin Films of CuI and Nanocellulose

Abstract

In this study we present a new flexible thin-film thermoelectric (TE) material consisted of biocompatible and biodegradable polymer nanocellulose (NC) as substrate and thin films of copper iodide $(\gamma-CuI)$ as a basic TE p-type semiconductor. For a preparing 8 $\mu m$ thick nanocellulose film we used a widespread plant common reed (Phragmites australis) and a fabrication process 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO)-mediated oxidation. The 1. $8-3.0\mu m$ thick nanostructured films CuI were deposited onto NC substrates via low-temperature aqueous cheap, facile, and scalable fabrication technique Successive Ionic Layer Adsorption and Reaction (SILAR). Thus we obtained TE material $NC/CuI$ with high thermoelectric power factor $S^{2}/\rho$ up to 60 $\mu W/(m\cdot K^{2})$. Lightweight flexible biodegradable thin-film TE modules based on thin-film samples NC/CuI were equipped with vacuum deposited thin Cr films providing ohmic contacts. Their output power densities up to 36 $\mu W/cm^{2}$ at difference of temperature between their ends 40 K, are comparable to those for state-of-the-art solid and flexible thermoelectric films.