Influence of size and surface state emission on photoluminescence of CdSe quantum dots under UV irradiation

Under UV irradiation, photo-oxidation occurs on the surface of CdSe quantum dots (QDs), thus modifying their QD optical properties. The influence of size and surface state (SS) emission on the photoluminescence (PL) evolution of CdSe QDs was investigated. Colorimetric study of the CdSe QD emission under UV irradiation indicates that the QD size and SS emission will influence the movement of chromaticity parameters. A photo-corrosion effect reduced the QD size and caused blue shift of the band edge (BE) peak. The irradiation-induced blue shift of QD emission always moves the corresponding chromaticity coordinate counterclockwise in the chromaticity diagram. For CdSe QDs with a dominant SS peak, the different evolution between BE and SS peak under UV irradiation will substantively influence the transformation of emission color: the chromaticity coordinate moved faster when PL increased than that when it decreased. Generally, the emission color of CdSe QDs with relatively large size and weak SS peaks is more stable in irradiation process.