Ligand‐Free Multi‐Scale CuAgSe Micro‐Nanoparticles with a Dendritic Structure for Application as a Room Temperature Thermoelectric Material

Abstract Exploring non‐BiSbTe thermoelectric (TE) materials operable in the near room temperature range has emerged as a vibrant research frontier. However, the current synthesis of such materials heavily relies on energy‐intensive techniques, with harsh conditions and the use of toxic reagents. In this work, a scalable, safe, simple, and cost‐effective solution‐based method is reported for synthesizing β ‐CuAgSe materials with a topologically dendritic structure. Notably, the synthesized material's surface is free from the complex organic ligands typically left by conventional synthesis methods, which mitigates the electrical performance degradation due to the intricate structure. Meanwhile, the multi‐scale phonon scattering induced by the complex structure leads to a reduction in thermal conductivity. As a result, the material achieves a maximum ZT max of 0.48 at 298K and ZT ave of 0.42 in the 298–348K range, surpassing other doped CuAgSe materials and ranking among the top in various materials synthesized via solvothermal methods. The successful fabrication of thermoelectric devices (TED) enhanced with integrated radiative cooling and TE pastes formulated from these materials demonstrates their potential for applications in flexible TE.