Highly luminescent CuInS²/ZnS (CIS/ZnS) core/shell quantum dots which have quantum yield of 65 % were synthesized by cation exchange reaction. Similar sized CIS core and CIS/ZnS core/shell which were confirmed by the TEM images revealed that cation exchange occurred inside core, as a result, reduced core size and large blue-shifted emission. Elemental analysis by the ICP revealed the CIS cores have gradient composition that is richer in indium close to the surface of the core, which could explain broad emission spectrum. Cation exchange reaction could be applied to AgInS² (AIS) QDs, which showed blue-shift of 70 ㎚ in the emission spectrum. PXRD pattern also showed peak shift as an evidence of core/shell structure.
