Comparison of thermoluminescence spectra of MgB4O7 doped with dysprosium and manganese

A series of magnesium borate phosphors MgB4O7:Dy, MgB4O7:Mn and MgB4O7:Dy, Mn were prepared and their thermoluminescence (TL) emission spectra were measured. TL emission bands in 480, 575 and 660 nm at 200 and 360 °C were observed in the MgB4O7:Dy due to the transitions of the trivalent rare earth ions Dy3+. The glow peaks of broad wavelength band around ∼580 nm at 180 and ∼290 °C were observed in MgB4O7:Mn due to the emission of Mn2+ ions. The main glow peak of MgB4O7 co-doped with Dy and Mn appeared in 580 nm at ∼360 °C. When MgB4O7 was co-doped with Dy (0.5 mol.%) and different concentrations of Mn (0.01 mol.%–1.0 mol.%), the peak in 580 nm at 360 °C was intensified and broadened as the concentration of Mn increased, while the peaks in 480, 680 and 750 nm below 300 °C remained the characteristic emission of Dy3+ and were reduced in intensity. The emission spectra of the MgB4O7:Dy, Mn phosphor showed that the competitive de-excitation processes between Dy3+ and Mn2+ existed and the energy transfer occurred from Dy3+ to Mn2+. These results meant that rare earth and Mn ions in MgB4O7:Dy, Mn might cause the formation of defects complex that dominated the traps and recombination.