IR Emission Band and Multiple-Peak Structure in Photoluminescence Spectra of SnO₂:Mn

SnO 2 :Mn phosphor was synthesized by chemically etching metallic Sn and Mn shots in aqueous HNO 3 solution. The synthesized phosphor was investigated by photoluminescence (PL), PL excitation spectroscopies, and PL decay time measurements. The PL spectra of SnO 2 :Mn exhibited a strong IR emission at ∼800 nm and green/red (G/R) emission. The G/R emission band was also observed in undoped SnO 2 . These emission bands were attributed to the Mn 2+ (IR) and Sn 2+ (G/R) ions in the SnO 2 host, respectively. The IR emission band exhibited multiple-peak structure with an energy interval of ∼13 meV, in agreement with the Fourier transform analysis. The activation energies of the IR and G/R emission bands were determined to be ∼0.3 eV. The PL decay times were ∼2 ms and ∼2 μ s for the IR and G/R emissions, respectively. The integrated PL intensity for the IR emission band showed a gradual increase with increasing temperature at T = 20–130 K. These unique tempearture dependence and multiple-peak structure were well explained by the configurational-coordinate model with the aid of the Franck–Condon principle. Resonant energy transfer from Sn 2+ to Mn 2+ is the cause of an appearance of the IR emission band in SnO 2 :Mn.