Directing semiconductor nanorod assembly into 1D or 2D supercrystals by altering the surface charge.

Coulomb repulsion due to the surface charge on semi-conductor nanorods works against the dipole-dipole attraction that tends to direct the nanorods to self-assemble; the nature of this self-assembly for CdSe nanorods can be thus altered by pyridine washing, which charges the rods surface--thereby allowing the Coulomb repulsion to tailor the alignment.