Synthesis of highly luminescent Cd (Se,S) nanocrystals

Highly luminescent semiconductor nanocrystals with graded band gap were synthesized using hot injection method. The band gap of nanocrystals were controlled by gradual incorporation of sulfur to CdSe nanocrystals by applying severely asymmetric composition of reactants ([Cd]/[Se,S]≫1). The maximum emission wavelength of the grown nanocrystals was varied by controlling the concentration ratio of VI group element, ie. Se and S. A green light was emitted from Cd (Se,S) nanocrystals with [Se]:[S]=1:3 in the reactant mixture and the maximum quantum yield measured by comparing with Rhodamine 6G was larger than 80%.