Tweaking the chemicals used to form nanorods can be used to control their shape.Controlling a nanorod’s shape is a key to controlling its properties. Researchers used a combined experimental and theoretical approach to show that precursor reactivity determines the relative ease of formation of different nanocrystals. Specifically, photocatalysts made from tiny amounts of cadmium, sulfur and selenium will form selectively into shapes that look like either tadpoles or drumsticks depending on the relative reactivity of the selenium and sulfur precursors. The more strongly bound the selenium or sulfur is to phosphorous in the precursor, the lower the reactivity. The lower the reactivity, the longer the nanorod and the more it is shaped like a tadpole. Purposely altering and modulating chemical reactivity of reactants will contribute to the development of more predictable routes to fabricate nanostructures with highly specific properties.
Molecular Control of the Nanoscale: Effect of Phosphine—Chalcogenide Reactivity on CdS—CdSe Nanocrystal Composition and Morphology