Luminescence and Electron–Hole-Trapping Centers in α-Ca2P2O7−Mn

Abstract

The mechanisms of formation of induced intrinsic and impurity radiative states, which consist of intrinsic and impurity electron–hole-trapping center states in irradiated 𝐶⁢𝑎2⁢𝑃2⁢𝑂7 −𝑀⁢𝑛 and 𝐶⁢𝑎2⁢𝑃2⁢𝑂7 phosphates, were investigated using thermoactivation and vacuum-ultraviolet spectroscopy methods. These centers are excited at photon energies of 4.0 eV and 4.5 eV, which are within the matrix’s transparency region. New radiative-induced states at 3.06 eV and 2.92 eV are demonstrated to be generated upon the excitation of anions by photons with energies of 5.0 and 5.64 eV. This process is due to charge transfer from the ion to the impurities, specifically 𝑀⁢𝑛2+⁢(𝑂2−−𝑀⁢𝑛2+) and the neighboring ion 𝑂2− −(𝑃2⁢𝑂7)4−. Furthermore, upon the excitation of matrix anions with photon energies exceeding the band gap (8.0–8.25 eV), electron-trapping by impurities such as 𝑀⁢𝑛2+ and (𝑃2⁢𝑂7)4− ions results.