Ultra-flexible organic-inorganic hybrid Bi2Te3 thin films for thermoelectric generators

Abstract

Achieving high thermoelectric (TE) performance and flexibility is essential for wearable electronics. Here, an organic-inorganic hybrid strategy incorporating methylammonium lead iodide (MAPbI₃) into Bi₂Te₃ thin films enhances both TE and mechanical properties. Pb/I incorporate into Bi₂Te₃ lattice, improving electrical conductivity via enhanced carrier transport and moderate doping effects. Meanwhile, amorphous phases derived from MA-related species strengthen phonon scattering, reducing κ_l+κ_bi from 1.1 Wm^-1K^-1 to 0.1 Wm^-1K^-1. As a result, the zT value improves from 0.08 to 0.94 at 250 °C. Moreover, the amorphization effect induced by the amorphous inclusions enhances flexibility by reducing the Young's modulus, yielding a resistance change of <7 % (ΔR/R₀) after bending. Specifically, the 0.6 wt. % sample exhibits only a 2.5 % resistance change after 5000 bending cycles. Finally, a flexible TE generator fabricated with hybrid films and Ag electrodes delivers a high output power of 35.3 nW under a 20 °C temperature gradient, highlighting the potential of this hybrid approach for wearable electronics.