Facile One‐Pot Solvothermal Synthesis of Bi 2 Te 3 Nanoplate/Te Nanorod Composites with High Seebeck Coefficients for Flexible Film‐Based Thermoelectric Generators

We report a one‐pot solvothermal route to Bi 2 Te 3 nanoplate/Te nanorod composites, eliminating the multiple synthesis cycles required for hybrid nanostructures. Structural analyses reveal that Sb acts as a growth inhibitor, with no significant lattice incorporation detected. The Bi:Te ratio sets the phase assemblage, whereas Sb regulates crystallite size, so that finely divided 2D nanoplates and 1D nanorods form in a single step. Bulk optimization identified Sb ratios of 0.00 and 0.85 as optimal n ‐type and p ‐type compositions, balancing Seebeck coefficient against electrical conductivity. Drop‐cast films on polyimide exhibit stable thermoelectric behavior, reaching −127 µV/K ( n ‐type) and 323 µV/K ( p ‐type) at 393 K, among the highest Seebeck coefficients reported for Bi 2 Te 3 ‐based flexible films. This primarily reflects the refined nanostructures produced by Sb‐mediated growth suppression, with interfacial energy filtering at most secondary. A flexible p ‐ n ‐junction thermoelectric generator (TEG) generated 6.2 mV at Δ T = 5.6 K (area‐averaged by infrared thermography; 7.7 K inferred from the Seebeck coefficient). Although below the ∼20 mV required by typical DC‐DC converters, the high per‐junction voltage indicates that series scaling can reach this threshold. This one‐step, voltage‐centric strategy offers a scalable route to flexible harvesters addressing the cold‐start voltage barrier of low‐power Internet of Things (IoT) electronics.