Emission Red Shift and Unusual Band Narrowing of Mn²⁺ in NaCaPO₄ Phosphor

Abstract

Concentration dependence of Mn(2+) luminescence in NaCaPO(4)/Mn(2+) is investigated by structural analyses and optical and laser excitation spectroscopies in the temperature range 19-300 K. NaCaPO(4)/Mn(2+) forms solid solution over the Mn(2+) concentration range 1.0-22 mol %. We observe the red shift and unusual band narrowing of Mn(2+) emission by increasing Mn(2+) concentration in NaCaPO(4). The lifetime of Mn(2+) emission lengthens unexpectedly for higher Mn(2+) concentration. The results are discussed in relation with crystal structure, photon reabsorption, exchange interaction, and energy transfer and energy migration in NaCaPO(4)/Mn(2+).

β-Zn3BPO7:Mn2+: A novel rare-earth-free possible deep-red emitting phosphor

“…As the fluorescence lifetime is often defined as the time of the fluorescence intensity decreased to 1/e of initial intensity, the fluorescence lifetime can be estimated to be about 9.6 ms, which is typical for the parity and spin-forbidden 4 T 1 ? 6 A 1 transition of Mn 2+ [6]. The above result indicates that the Mn 2+ ion in b-Zn 3 BPO 7 host has a fast decay time in the order of millisecond.…”

“…2(a), the excitation spectrum consists of a broad excitation band peaking at 255 nm around 220 and 300 nm and a group of line-shaped excitation peaks around 350 nm and 500 nm. For the latter, they can be assigned to the inner d-d electron transitions of Mn 2+ ion, in which the highest peak at 402 nm belongs to the transition from the ground state 6 A 1 ( 6 S) to the [ 4 A 1 ( 4 G), 4 E( 4 G)] levels [1,6,10]. The intensities of these transitions are very weak because they are spin-forbidden.…”

“…6 A 1 transition of Mn 2+ ion within the 3d shell. The 3d electrons are strongly coupled to lattice vibration and affected by crystal field strength, which leads to the emission wavelength of Mn 2+ ions dependent strongly on the host lattice, varying from green to deep-red region [6], so Mn 2+ ion can also be used as a structural probe ion. Classically, Mn 2+ ions in the tetrahedral coordination often show green-light emission, whereas the octahedrally coordinated Mn 2+ ions can give orange to red emission.…”

Optical properties of Sm3+ and Dy3+ ions in Gd2MoB2O9 host lattice

“…The average lifetime from non-exponential decay curves can be calculated using the following equation [18,19]:…”

Probing luminescence centers in Na rich feldspar

“…This emission in the host lattice typically occurs with a lifetime of the order of tens of milliseconds within the 3d shell, where the electrons are strongly coupled to lattice vibration and affected by crystal field strength and site symmetry (e.g. Shi et al, 2010). In our phosphorescence data, we observe the dominant lifetimes of the order of hundreds of microseconds to less than a fraction of a millisecond, which is not consistent with the interpretation that the green emission is arising from discrete Mn 2+ defects.…”