Core-shell structure and photoluminescence of CdS quantum dots

A double-potential-well model is proposed to describe the core-shell thickn ess-dependent photoluminescence peaks and energy relaxations in semiconduct or quantum dots (QDs). The surface effect plays an important role in the fo rmation of new states-polaronic states around the surface of QDs. The polar onic states formed emit light due to the strong interaction between the cor e state (con-fined state) and the surface state with an enhanced participat ion of the size effect.