Application of Spectroscopic Probes in Study of Ferroelectrics

Abstract

A 2 ) and vibrational sidebands. It is suggested that unusually large temperature shift of ZPL is caused mainly by the contribution of the lowest TO soft optical branch into interaction of emitting center with a lattice. The PL spectrum of Cd 2 Nb 2 O 7 :Cr 3+ consists of four narrow emission lines accompanied by vibrational sidebands. Emission lines are attributed to the zero-phonon transitions 2 E → 4 A 2 of two kinds of octahedral coordinated Cr 3+ centers. The change in activation energies of PL thermal quenching at T c = 196 K is tentatively explained by a change of the adiabatic potential of the Cr 3+ centers at the ferroelectric phase transition of Cd 2 Nb 2 O 7 at T c . The low-temperature photosensitivity of both materials is attributed to the photoinduced change of charge state of manganese and chromium centers.

Photo-induced degradation and thermal decomposition in ZnSnF6·6H2O:Mn4+ red-emitting phosphor

“…The PL spectrum in Fig. 2 gives the sharp red emission lines typically observed in various Mn 4+ -activated phosphors [25][26][27][28][29][30]. This PL spectrum is also found to be nearly the same as those observed in the trigonal ZnSiF 6 Á6H 2 O:Mn 4+ and ZnGeF 6 Á6H 2 O:Mn 4+ phosphors, as demonstrated in Fig.…”

Probing local site environments and distribution of manganese in SrZrO3:Mn; PL and EPR spectroscopy complimented by DFT calculations

“…There is a peak at around 250 nm, which is ascribed to the host absorption band (HAB), arising due to O to Zr charge transfer. [54][55][56][57][58] The absence of such peaks eliminates the possibility of stabilizing Mn as Mn 4+ in the matrix. 3b.…”

Deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics for plant lighting

“…The nephelauxetic ratio β 1 in this Fig. 9 Dependence of Mn 4+ 2 E g energy level on the β 1 value in different hosts [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50].…”