Color Manipulation of Intense Multiluminescence from CaZnOS:Mn²⁺ by Mn²⁺ Concentration Effect

Abstract

Color manipulation of intense multiluminescence from CaZnOS:Mn2+ has been realized by adjusting Mn2+ concentration. Not only the photoluminescence (PL) of Mn2+ emission from 4T1(4G) to 6A1(6S) shows a red shift from yellow to red with increasing Mn2+ concentration, which is in contrast to the fixed PL emission reported by Hintzen et al. (Chem. Mater., 2009), but also mechanoluminescence (ML) and cathodoluminescence (CL) have a similar variation. More attractively, the brightness of multiluminescence is surprisingly intense for all the CaZnOS:Mn2+ with a large-scale Mn2+ doping (0.1–10 mol %). Based on the investigation of crystal field, various spectral results, and PL lifetimes, the red-shift mechanism of multiluminescence reported here has been proposed to arise from the exchange interaction effect of Mn2+ pairs at higher concentrations. In addition to correcting the previous misunderstanding on the emission of CaZnOS:Mn2+, these findings extend the tunable emission window, opening up new opportunities in multifunctional applications of PL, ML, and CL involving multicolor light sources, displays, and stress imaging, especially providing a novel resolution to design ML colors.

Luminescence, Plasmonic, and Magnetic Properties of Doped Semiconductor Nanocrystals

“…Schematic presentations of the doped nanocrystals with variation of dopant concentration are shown in Figure 2b. Inset shows the plot of decay time as afunction of Mn to Zn ratio.Q ualitatively similar, but quantitatively less pronounced results have also been reported for CaZnOS, [31] with the excited state decay lifetime decreasing rapidly with the dopant (Mn 2+ )c oncentration, as shown in Figure 2d. Fort he nanocrystals having average 32 Mn atoms per crystal the lifetime measured was 850 ms, but with average 431 atoms per crystal it was reduced to 100 ms.…”

“…a) Optical spectra of Mn-doped ZnSe with variationo fMncontent. and Ref [31],. c) Excited state decay lifetime plots for Mn-doped ZnSe nanocrystals with different Mn content.…”

Red‐Tuned Mn d–d Emission in Doped Semiconductor Nanocrystals

“…These long lifetimes might be due to the interaction of the neighboring elements or surface ligands with Mn ligand fields. It has been reported very recently that for the host CaZnOS, the emission was redshifted and the lifetime decay varied with increase in Mn concentration; the higher the Mn content in the crystal, the shorter the PL lifetime of the 4 T 1 → 6 A 1 emission. Figure a shows the digital images of illuminated samples, which show color variation with changes of Mn concentration and Figure b presents the change in decay time with Mn concentration.…”

Energy harvesting and conversion mechanisms for intrinsic upconverted mechano-persistent luminescence in CaZnOS

“…20,21,37,83 Eqn (9) and (10) show the cases of single luminescence peaks within different charge states due to the subtle interplay of multi-defect reactions. For a single persistent luminescence peak with ÀU eff for O-defects, eqn (11) seems to be valid in many cases. Considering eqn (5a), the intensity of three independent chain reactions is shown as follows:…”

“…[7][8][9] Recent studies performed by Xu et al 5,10 demonstrated a substantial leap in this field, showing that some ML materials, such as oxy-sulfides, can also be applied as persistent luminescence materials through transition metal doping and have flexible color manipulations. 11 This requires us not only to understand the electronic structures that originate from extrinsic doping, but also makes it highly necessary to plot the photonelectron dynamic transitions based on the subtle energy conversion mechanisms during the process of persistent luminescence. Currently, stronger intensity, longer time and lower cost with flexible wavelength in persistent luminescence are increasingly needed as the demands of electronic device integration, biochemistry and materials engineering rapidly expand.…”