Solvothermal Synthesis of V-VI Binary and Ternary Hexagonal Platelets: The Oriented Attachment Mechanism

General synthesis of both binary and ternary V-VI based thermoelectric alloy hexagonal platelets was carried out for the first time in a unified system using a modified solvothermal method, which adopted convenient oxides as source materials and friendly ethylene glycol as both solvent and reducing agent. The structure and composition analysis reveal that the samples are pure phase with corresponding atomic ratios. Electron microscopy results indicate that the as-prepared products are uniform and highly crystallized. The formation process was studied in detail by observing time-dependent products, and it was found that the oriented attachment mechanism could be responsible for the growth of these hexagonal platelets, which exhibits intrinsic difference compared with the inferred seed-mediated growth mechanism in previous reports. The influence of pH value and polyvinyl pyrrolidone on the morphology of the products was investigated as well. This work may open up a new rationale on designing the solution synthesis of nanostructures for materials possessing similar intrinsic crystal symmetry.