Single‐Crystalline Colloidal Quasi‐2D Tin Telluride

Abstract

Tin telluride is a narrow gap semiconductor with promising properties for IR optical applications and topological insulators. We report a convenient colloidal synthesis of quasi-two-dimensional SnTe nanocrystals through the hot-injection method in a nonpolar solvent. By introducing the halide alkane 1-bromotetradecane as well as oleic acid and trioctylphosphine, the thickness of two dimensional SnTe nanostripes can be tuned down to 30 nm, while the lateral dimensional can reach 6 μm. The obtained SnTe nanostripes are single-crystalline with a rock-salt crystal structure. The absorption spectra demonstrate pronounced absorption features in the IR range revealing the effect of quantum confinement in such structures.

Template-Mediated Formation of Colloidal Two-Dimensional Tin Telluride Nanosheets and the Role of the Ligands

“…In previous studies, we observed that halogenated compounds have an important influence on the shape of semiconductor nanomaterials. ,,, The active species promoting the shape transformation and confined growth were halide ions produced in situ which influence both the nucleation and ripening of the nanostructures . We also evidenced that the amount of 1-chlorotetradecane (1-CTD) is one of the key factors for obtaining relative uniform and well-defined 2D SnTe nanostripes while only agglomerates were produced if no haloalkanes were used during the synthesis of SnTe nanostructures . The importance of 1-bromoheptane (Br-Hep) in the formation of CdSe nanosheets was earlier revealed, suggesting that two active species, Br-Hep and ionic Br – , were present on the surface of the CdSe nanosheets and partially replace the carboxylate ligands .…”

“…As a IV–VI narrow bandgap semiconductor (0.18 eV, bulk), SnTe exhibits an intrinsically high charge carrier concentration, which results in a relatively low Seebeck coefficient, , but optimization of the material through doping and alloying offers great promise for thermoelectric applications of this material . SnTe has also gained significant interest due to its exciting properties as a topological crystalline insulator, IR detection and radiation receiver material, and photovoltaic absorber. − So far, attempts to obtain solution-based SnTe nanocrystals (NCs) mainly yielded zero-dimensional (0D) or one-dimensional (1D) nanostructures. − Recently, we reported a synthesis protocol for two-dimensional (2D) colloidal SnTe nanostructures . Now, we disclose the important role of ligands in the colloidal synthesis process information about the 2D morphology and the observed faceting of nanocrystals.…”

Colloidal Two-Dimensional Metal Chalcogenides: Realization and Application of the Structural Anisotropy

“…By electrical transport characterizations, fascinating properties of individual colloidal nanoplatelet and nanosheet were revealed, such as structure- and spin-dependent optoelectronic responses. The discoveries shed light on their tremendous potential of being used as building blocks in electronics and photonics, including surface-defined materials with topological states for spin transport, low-threshold pulsed or continuous wave lasers, quantum sensors, light-emitting diodes, and solar cells.…”

“…Li et al found that the optimized configuration of monolayered SnTe isolated from the bulk orthorhombic SnTe had a lower symmetry ( Pmn 2 1 ) . Recently, our group synthesized quasi-two-dimensional SnTe nanostripes with a lateral size of up to 6 μm and thicknesses below 30 nm using a one-pot hot injection method . These SnTe nanostripes were found to display a cubelike rock salt structure and show pronounced absorption features in the IR range.…”

“…49 Recently, our group synthesized quasi-two-dimensional SnTe nanostripes with a lateral size of up to 6 μm and thicknesses below 30 nm using a one-pot hot injection method. 50 These SnTe nanostripes were found to display a cubelike rock salt structure and show pronounced absorption features in the IR range. Despite the extensive studies on colloidal SnX nanosheets, finding ways to refine the crystal thickness and eliminate surface oxidation are still major tasks.…”