Synthesis Of Co-Doped Aqueous ZnSe Quantum Dots And Optical Property Tuning

Co-doped quantum dots(QDs) can be regarded as QDs which have incorporated with two different kinds of metal ions. Many types of co-doped ZnSe QDs with tunable fluorescence can be synthesized by controlling the type of metal ions. In this work, we studied the synthesis and tuning of optical properties of co-doped ZnSe QDs in aqueous media, the main results are shown below:Ag,Mn:ZnSe QDs with improved monochromaticity were synthesized in aqueous solution by co-doping non-irradiative Ag inside QDs. The optical filtering effect of Ag can be achieved by controlling experimental conditions including pH values, MPA/Zn ratios and growth time. By research in the exciton relaxation dynamics information with and without Ag doping, we can see that, the co-doping of Ag into Mn:ZnSe QDs leads to decreased irradiative decay rates of ZnSe band gap emission (krZnSe) and efficiency of electron transfer from ZnSe conduction band to defects energy level (?ETTS) but cannot decrease the efficiency of electron transfer from ZnSe conduction band to Mn energy level (?ETMn), thus ZnSe band gap and ZnSe trap emission can be suppressed. In this work, the observed optical filtering effect inside QDs for the first time. This work is also helpful to comprehend the coordination effect of non-irradiative dopants inside a single QD.Aqueous Cu,Mn:ZnSe QDs were prepared via a nucleation doping strategy by co-doping Cu2+ and Mn2+, precise control for the PL peaks and ratios of the multiple emission Cu,Mn:ZnSe QDs was realized by controlling the experimental conditions including pH values, MPA/Zn ratios and growth time. White emission was realized by manipulating Cu dopant emission and Mn dopant emission in a single QD. This work provides white light materials for QDs light emitting diodes.