Boosting the Thermoelectric Performance via Dynamic Cu Doping in GeTe

Thermoelectric performance of GeTe across broad temperature ranges is fundamentally constrained by its temperature‐dependent optimization of carrier concentration, where traditional static doping cannot satisfy. Here, we present a dynamic doping strategy that can harness temperature‐driven Cu migration to achieve temperature‐dependent carrier optimization. At low temperatures, Cu preferentially occupies interstitial sites, effectively suppressing excessive intrinsic carrier concentrations. With increasing temperature, Cu migrates to cationic substitutional sites, acting as acceptor‐like dopants. This adaptive behavior maintains the carrier concentration within the optimal range at both low and high temperatures while introducing localized lattice strains that suppress the lattice thermal conductivity approaching the amorphous limit. Consequently, a peak figure of merit ( ZT ) reaching ∼2.4 at 673 K and an average ZT of ∼1.6 across 300–773 K are achieved. A four‐legged module is constructed and achieves a power density of ∼5.9 KW m −2 with a temperature gradient of ∼360 K. This study establishes adaptive carrier regulation via dynamic doping as a key mechanism for achieving high thermoelectric performance across a wide temperature range.