Structure and photoluminescence properties of a rare-earth free red-emitting Mn²⁺-activated KMgBO₃

Abstract

In this combined X-ray diffraction and photoluminescence study, the coordination environment of Mn(2+) and the photoluminescence of single Mn(2+) doped KMgBO3 phosphors were studied. Mn(2+) occupies Mg(2+) sites, which were coordinated by six O(2-). The strong absorption of KMgBO3:Mn(2+) was ascribed to the strong relaxation of spin and parity forbidden d-d transitions of Mn(2+). The emission bands were centered at 636 nm, regardless of the excitation wavelength and Mn(2+) doping concentration. Mn(2+) activated KMgBO3 could be efficiently excited with the excitation of Mn(2+) d-d transitions in the wavelength range of 300-475 nm. The red-shift of Mn(2+) emission was because of the strong crystal field environment of Mn(2+) afforded by KMgBO3. The potential applications of the phosphors have been pointed out based on their absorption spectra, excitation and emission spectra, thermal quenching properties, and decay properties.

Abnormal luminescent property of Mn2+ in α-LiZnBO3:Mn2+

“…Eu 2+ (60 nm), 20 KMgBO 3 :Mn 2+ (70 nm). 21 It can be observed that the emission band is asymmetric. This phenomenon is caused mainly by efficient energy transfer from the defectrelated emission.…”

Site occupancy and photoluminescence properties of Eu3+-activated Ba2ZnB2O6 phosphor

“…18,19 In order to prove the Eu 3+ ions occupy Zn 2+ sites in Ba 2 ZnB 2 O 6 : Eu 3+ , the renement of the XRD patterns of Ba 2 ZnB 2 O 6 :Eu 3+ by Rietveld method 20,21 within the Fullprof Program 22 were performed. Renement of the structure parameters from diffraction data can obtain the crystal structure properties, such as the lattice parameters, the atomic positions of the doped ions, and occupancies.…”

“…Renement of the structure parameters from diffraction data can obtain the crystal structure properties, such as the lattice parameters, the atomic positions of the doped ions, and occupancies. 18,19 In order to prove the Eu 3+ ions occupy Zn 2+ sites in Ba 2 ZnB 2 O 6 : Eu 3+ , the renement of the XRD patterns of Ba 2 ZnB 2 O 6 :Eu 3+ by Rietveld method 20,21 within the Fullprof Program 22 were performed. It is found that the Ba 2+ sites cannot be occupied because of the nal agreement factors are very high and the occupancy of Eu 3+ on this site is far away from the nominal doping content.…”

Oxygen vacancy content drives self-reduction and anti-thermal quenching

“…31 The decay lifetimes of the three decay curves all gradually decrease with increasing dopant contents because of the rising possibility of exchange interaction between Mn 2+ ions. 32 The difference in the lifetimes of different decay curves comes from the different energy transition rate of different luminescent centers. 33 In addition, the concentration-dependent PL spectra are evaluated in Fig.…”

“…S2 (ESI †), in which the intensity increases with the dopants until reaching a maximum at x = 0.14 and then decreases due to the exchange interaction between Mn 2+ ions. 32 To verify the valence state of Mn ions in the doped samples, K-edge X-ray absorption near edge structure (XANES) is usually regarded as a powerful tool, from which the Mn edge and preedge absorption peak of LZPM 0.14 are more coincident with those of MnO rather than MnO 2 (Fig. 2b).…”