An Organic–Inorganic Superlattice with Nanocrystal‐Amorphous Composite Nanolayers for Ultrahigh Thermoelectric Performance

Thermoelectric materials play a crucial role in converting heat into electricity, offering significant potential for applications in waste heat recovery and cooling. Herein, an innovative approach that combines an organic–inorganic hybrid superlattice structure with nanocrystal‐amorphous composite nanolayers is introduced. The nanocrystal‐amorphous composite enhances the Seebeck coefficient resulting in a notable twofold improvement in the power factor. The superlattice, alternating self‐assembled organic monolayers and inorganic nanolayers, effectively reduces lattice thermal conductivity by creating multiple interfaces that scatter phonons effectively. The integration of the nanocrystal‐amorphous composite nanolayers into the superlattice provides a dual advantage, simultaneously boosting the power factor and suppressing thermal conductivity. This synergistic effect leads to exceptional thermoelectric performance in the 4‐mercaptophenol/Sb 2 Te 3 superlattice, with achieved figure of merit (ZT) values of 3.48 at 300 K and reaching a peak ZT value exceeding 4.0 at 400 K while surpassing 2.5 over the temperature range from 300 to 500 K. These results suggest that this innovative approach paves the way for the development of highly efficient thermoelectric materials, propelling efforts toward more energy‐efficient and environmentally friendly solutions.