The spontaneous-reduction of Mn7+or Mn4+to Mn2+with intense Mn2+-photoluminescence or afterglow luminescence has been first demonstrated in Zn2GeO4and A2BGeO4(A = Li, Na; B = Mg, Zn) synthesized by a high temperature solid state reaction method in air.

The valence manipulation of emissive Mn ions (Mn2+/Mn4+) in Ba0.75Al11O17.25–BaMgAl10O17 solid solutions and their corresponding application in temperature-sensing have been demonstrated by defect control along with composition variation.

An accurate measurement of radiation doses is required to ensure efficient use of electromagnetic radiation in medical diagnostics, agriculture, or general lighting applications. Yet, existing dosimeters usually face the issues of cumbersome manipulation, time-consuming analysis, or power-supply requirement. Here, an all-round dosimeter is reported based on BaMgSiO 4 , a photochromic material that exhibits a reversible white-pink color change upon irradiation. Electron paramagnetic resonance measurements under in situ coloring and bleaching reveal that the charge carrier trapping and detrapping at oxygen vacancy-related defects determine the photochromic behavior. This can be utilized for dosimetry of X-rays, ultraviolet, and visible light, as the coloring and bleaching are dependent on the irradiation wavelength and the dose. The distinct color variation of BaMgSiO 4 allows for on-site measurement of irradiation doses by a colorimetric method, and the special wavelength-responsive behavior in the ultraviolet region is suitable for personal solar ultraviolet light monitoring. By virtue of good stability and excellent cycling robustness, BaMgSiO 4 can be an ideal integrating detector for X-rays, ultraviolet, and visible light dosimetry. A prototype device is also developed for long-duration daylight measurements. These findings enhance the understanding of the photochromic behavior in inorganic materials and can stimulate the exploration of new photochromic dosimeters.

The different Mg/Zn ratios of (Mg1−xZnx)2.97(PO4)2:0.03Mn2+ result in various PL intensities and spectra profiles, which are related to the crystal field strength and local environment of the Mn2+ ions.