Monodisperse core/shell and other complex structured nanocrystals and methods of preparing the same

A composition comprising nanocrystalline, core/shell/shell quantum wells, wherein:

• the quantum wells comprise a core material, a first shell material overcoating the core material, and a second shell material overcoating the first shell material;
• the core material comprises a stable, nanometer-sized inorganic solid;
• the first shell material and the second shell material are independently selected from a II/VI compound or a III/V compound;
• the band gap of the first shell material is less than the band gap of the core material and less than the band gap of the second shell material;
• and
• the as-prepared quantum wells exhibit a photoluminescence that is substantially limited to a bandgap emission, with a room temperature photoluminescence quantum yield from 10% to 60%.