(101d) Synthesis of Sne (E=S,Se) Nanocrystals with Controlled Morphology and Investigation of Their Electronic Properties

Solution-processed electronic and optoelectronic devices are of great interest due to their potential to enable low cost and industrially-favorable fabrication processes. Cadmium, lead, or/and tellurium-based nanocrystals (NCs) are the best-studied materials for these applications, but cannot ultimately be used in all applications, because of their scarcity and/or toxicity. In this work, we study tin-based semiconductor NCs, which are relatively non-toxic and abundant materials compared with cadmium-based NCs. We provide a facile method to size-controllably synthesize SnSe QDs based on air-stable and low-cost chemicals. Moreover, we synthesize colloidal single-crystalline SnS and SnSe nanosheets by combining different ligands to suppress nanocrystal growth along specific directions in the crystal lattice. These colloidal single-crystalline nanosheets not only facilitate fabrication of thin film by casting, coating and printing, but are also also more favorable for charge transport compared to small NC-based thin film. This is a result of improved contact between overlapping nanosheets compared to adjacent quasi-spherical nanocrystals.