Free-standing ZnS:Cu and ZnS:Cu,Al quantum dots were prepared in the aqueous medium from readily available
precursors. The construction, morphology and luminescence properties of the ZnS:Cu and ZnS:Cu,Al quantum dots were
evaluated by XRD,TEM and photoluminescence spectra. The average particle size was calculated using the Scherrer
formula to be 5nm, which is also observed from HRTEM image. In PL spectra, 0.7% Cu and 0.4% Cu -doped ZnS:Cu
quantum dots have emission peak around 470 nm and 500 nm, which attributed to the transition from the shallow donor
level (sulfur vacancy) to the e level and t2 level of Cu2+ respectively. And PL spectra of ZnS:Cu,Al quantum dots is
similar with the PL of ZnS:Cu quantum dots, but the luminescence intensity of quantum dots ZnS:Cu,Al increase, which
arise from that Al 3+ ions as co-activated enhance donor level.
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