In Situ Design of High‐Performance Dual‐Phase GeSe Thermoelectrics by Tailoring Chemical Bonds

Composite engineering favors high thermoelectric performance by tuning the carrier and phonon transport. Herein, orthorhombic rhombohedral dual-phase GeSe are designed in situ tailoring chemical bonds. Atom probe tomography verifies coexistence of a covalently bonded phase metavalently GeSe-InTe alloys. The production simultaneously increases concentration, mobility, band degeneracy, density-of-states effective mass due to reduced formation energy cation vacancies improved crystal symmetry. These attributes beneficial high-power factor. In addition, thermal conductivity can be significantly intrinsically strong lattice anharmonicity phase, interfacial acoustic mismatch across different bonding mechanisms, scattering at vacancy-solute clusters. Moreover, embraces higher solubility dopants that enables further optimization properties Cd-Ag doping, resulting zT 0.95 773 K as well enhanced strength ductility Ge0.94Cd0.03Ag0.03Se(InTe)0.15. This work indicates design composites bonds is an method for enhancing mechanical other p-bonded chalcogenides.