Thin-films on cellulose paper to construct thermoelectric generator of promising power outputs suitable for low-grade heat recovery

Here, cellulose paper-based thermoelectric generators packaged inside Kapton layers are fabricated that demonstrate enhanced physical stability and flexibility with impressive power outputs at low temperature heating. The work introduces a successful combination of copper iodide (CuI) and bismuth (Bi) coated cellulose papers, two non-toxic and simple conductors which act as p-type and n-type legs in the generator, respectively. The power output characteristics of a generator comprising ten p-n junctions are measured and analysed at different temperature gradients. A high output voltage of 84.5 mV and corresponding output power of 215 nW are obtained from the device at a temperature difference (ΔT) of ~50 ºC, which is comparable to expensive and toxic thermoelectric devices reported in the literature. The presented device fabrication method is a very simple and economical approach to fabricate paper based eco-friendly thermoelectric devices that can be used for low-grade heat conversion applications.