Modulation Doping Leads to Optimized Thermoelectric Properties in <i>n</i>‐Type Bi₆Cu₂Se₄O₆ due to Interface Effects

Abstract Heterogeneous composites consisting of Bi 6 Cu 2 Se 3.6 Cl 0.4 O and are prepared according to the concept modulation doping. With prominently increased carrier mobility almost unchanged effective mass, electrical transport properties considerably optimized resulting in a peak power factor ≈1.8 µW cm −1 K −2 at 873 K, although concentration is slightly deteriorated. Meanwhile, lattice thermal conductivity lowered ≈0.62 W m due introduction second phase. The modified Self‐consistent Effective Medium Theory utilized explain deeper mechanism enhancement apparent derived from highly active phase interfaces as fast channels, while reduced ascribed existence resistance interfaces. Ultimately, an ZT ≈0.23 obtained + 13% Se. This research demonstrates effectiveness doping for optimizing thermoelectric once again, provides direct microstructure observation consistent theoretical model calculation emphasize role interface effects doping, which should be probably applicable other thermoelectrics.