Precursor-mediated linear- and branched- polytypism control in CuαZnβSnySeδ colloidal nanocrystals using a dual-injection method

Control of polytypism in colloidal nanocrystals allows for a shape evolution from 0D to 3D and also provides an opportunity to tailor physical properties that are crystal phase dependent. Initiating polytypism in nanostructures is a function of multiple different control parameters that dictate nucleation and growth, including reaction temperature, ligands, and precursors. This is further complicated as the number of metal ions increases in progressing from binary to ternary to quaternary compositions. Here, a synthesis method with dual injections is developed to initiate two- and three-dimensional polytypism in the nonstoichiometricαβδ CuαZnβSnγSeδ system simply by changing a single commercially available chemical precursor. Synthesis parameters were developed to grow single-crystal wurtzite and zinc-blende forms with a further extension to linear and branched morphologies deriving from nucleation in one phase and growth termination in the other. Photoluminescence measurements were carried out on the particles at a low temperature with emission peaks ranging from ∼1.93 to ∼2.32 eV observed.