Tin Diselenide Molecular Precursor for Solution-Processable Thermoelectric Materials

In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe₂ nanoplates (NPLs) and their use to produce crystallographically textured SnSe₂ nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism. This mechanism typically results in pyramidal structures, but we demonstrate here that the growth from multiple dislocations results in flower-like structures. Crystallographically textured SnSe₂ bulk nanomaterials obtained from the hot pressing of these SnSe₂ structures display highly anisotropic charge and heat transport properties and thermoelectric (TE) figures of merit limited by relatively low electrical conductivities. To improve this parameter, SnSe₂ NPLs are blended here with metal nanoparticles. The electrical conductivities of the blends are significantly improved with respect to bare SnSe₂ NPLs, what translates into a three-fold increase of the TE Figure of merit, reaching unprecedented ZT values up to 0.65.