High-Performance Flexible Thermoelectric Generator via Rapid Evaporation of Nanocrystalline Bi2Te3-Alloy Films

We demonstrate a high-performance flexible thermoelectric generator (FTEG) using nanocrystalline p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.7Se0.3 films deposited on polymer (PET) via rapid thermal evaporation (RTE) at room temperature. Without any annealing, these ∼1 μm films reach power factors of ∼1.5 and ∼1.2 mW·m–1·K–2 at 200 °C─among the highest for flexible Bi2Te3-based films. A 10-couple device yields ∼61 mV (446 nW) at ΔT = 25 °C and ∼13 mV at ∼10 °C on skin, demonstrating viable body-heat harvesting. RTE involves no high-temperature steps and is compatible with scalable, low-cost fabrication of wearable power sources.