All-Oxide p–n Junction Thermoelectric Generator Based on SnO<i>_x</i> and ZnO Thin Films

Achieving thermoelectric devices with high performance based on low-cost and nontoxic materials is extremely challenging. Moreover, as we move toward an Internet-of-Things society, a miniaturized local power source such generator (TEG) desired to increasing numbers of wireless sensors. Therefore, in this work, all-oxide p–n junction TEG composed low-cost, abundant, materials, n-type ZnO p-type SnOx thin films, deposited borosilicate glass substrate proposed. A type II heterojunction between films was predicted by density functional theory (DFT) calculations confirmed experimentally X-ray photoelectron spectroscopy (XPS). scanning transmission electron microscopy (STEM) combined energy-dispersive (EDS) show sharp interface the layers, confirming quality even after annealing at 523 K. exhibit Seebeck coefficients (α) ∼121 ∼258 μV/K, respectively, 298 K, resulting factors (PF) 180 μW/m K2 (for ZnO) 37 SnOx). thermal conductivities are 8.7 1.24 W/m no significant changes until 575 The four pairs generated maximum output (Pout) 1.8 nW (≈126 μW/cm2) temperature difference 160 voltage (Vout) current (Iout) 124 mV 0.0146 μA, respectively. This work paves way for achieving high-performance device oxide films.