Fig. 7: Experimental investigations on color centers and local piezoelectricity.
From: Dynamic multicolor emissions of multimodal phosphors by Mn2+ trace doping in self-activated CaGa4O7
a Diffuse reflectance spectra of CaGa4O7:Mn2+ before photoexcitation (gray line) and after photoexcitation (red line). The yellow curve shows the PL spectrum of Mn2+ in CaGa4O7:Mn2+. The inset shows an optical photograph of the CaGa4O7:Mn2+ disc, with photoexcitation applied to the right half. b ESR spectra of CaGa4O7:Mn2+ before photoexcitation (gray line) and after photoexcitation (red line). c PFM hysteresis loop of a CaGa4O7:Mn2+ particle (top, phase signal; bottom, amplitude signal). Source data are provided as a Source Data file.
