Shape control of CdSe/CdS nanocrystals during shell formation and growth: Dominating effects of surface ligands over core crystal structure

CdSe/CdS nanocrystals (NCs) are among the most studied semiconductor nanocrystals, yet there is still much information to be gained. This work reveals that core@shell NCs with different shapes more controlled by interaction between NC surface and capping ligands than core concentration, but not at all difference in crystalline nature of core. Among precursors, cadmium carboxylates promote an isotropic structure, while conversely, long-chain phosphonates favor anisotropic one. Cadmium critical formation headshell, play a role tail growth. Against expectations, CdSe-core crystal structure (zinc blende or wurtzite) plays very little determining final shape, which may due two-stage CdS shell process, gives rise tadpole shape. With appropriate ligands, precise control structures can achieved both shape growth process. We claim, here, morphologies as tadpoles, nanoflowers, dot-in-rods, tetrapods obtained only varying ligand ratios. unique crystal-growth mechanism applied other seed-mediated methods produce aniso-tropic nanostructures.