Enhancing Thermoelectric Performance and Flexibility of Sb2Te3 Thin Films through MAPbI3‐Induced Crystallographic Orientation Modulations and Interfacial Doping

Abstract Wearable thermoelectric (TE) devices have garnered significant attention, but achieving both high TE performance and flexibility in Sb 2 Te 3 ‐based systems remains a challenge. In this study, methylammonium lead iodide (MAPbI 3 ) is incorporated to simultaneously enhance the TE performance and mechanical flexibility of Sb 2 Te 3 thin films. The integration of MAPbI 3 introduces micro strain, modulating the crystal orientation by suppressing the (015) plane and enhancing the (00 l ) plane, leading to improved carrier mobility and electrical conductivity. Additionally, MAPbI 3 ‐induced interfacial doping reduces carrier concentration and increases the Seebeck coefficient. The introduced lattice defects, such as large‐angle grain boundaries, strengthen phonon scattering, significantly reducing thermal conductivity and yielding a high zT of 0.47 at 250 °C. The films demonstrate exceptional flexibility, as evidenced by a decrease in the resistance change ratio ( ΔR / R 0 ) from 54.6% to 8.7% upon MAPbI 3 incorporation, attributed to its lower Young's modulus. The fabricated device achieves a maximum output power of 33.5 nW under a temperature gradient of 10 K, consistent with finite element simulations, highlighting its promising potential for wearable electronics.