CuAlSe2 Inclusions Trigger Dynamic Cu+ Ion Depletion from the Cu2Se Matrix Enabling High Thermoelectric Performance.Atomic-scale incorporation of CuAlSe2 inclusions within the Cu2Se matrix, achieved through a solid-state transformation of CuSe2 template precursor using elemental Cu and Al, enables a unique temperature-dependent dynamic doping of the Cu2Se matrix.  Furthermore, the nanostructuring near the CuAlSe2/Cu2Se interface, as well as the extensive atomic disorder in the Cu2Se and CuAlSe2 phases, significantly increases phonon scattering, leading to suppressed lattice thermal conductivity.  This work demonstrates the use of in situ-formed interactive secondary phases in a semiconducting matrix as an elegant alternative approach for further improvement of the performance of leading thermoelectric materials.
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