Organic-SnSe₂ Hybrid Superlattice toward Synergistic Electrical Transport Optimization and Thermal Conductance...

Recently, layered SnSe₂ has drawn broad research interest as a promising thermoelectric material that possesses great potential for application in energy conversion. However, extensive efforts have been devoted to optimizing the thermoelectric performance of SnSe₂, but the ZT value is still far from satisfactory. Therefore, we developed an organic-inorganic superlattice hybrid by intercalating organic cations into SnSe₂ interlayers in an attempt to enhance the thermoelectric properties. Organic intercalants can enlarge the basal spacing and decouple the SnSe₂ layers, bringing about synergistic electrical transport modification and phonon softening. Thus, by simultaneously improving the electrical conductivity and reducing the thermal conductivity, a ZT value of 0.34 is achieved at 342 K in tetrabutylammonium-intercalated SnSe₂, approximately two orders of magnitude higher than that of pristine SnSe₂ single crystals. In addition, by opening van der Waals gaps via organic cations, outstanding flexibility of organic-intercalated SnSe₂ is realized, with a superior figure of merit for flexibility of approximately 0.068. This work demonstrates a general and facile strategy to fabricate organic-inorganic superlattice hybrids with a considerable improvement in the thermoelectric performance via organic cation intercalation, which is promising for flexible thermoelectrics.