Mechanism of broad-band luminescences in ZnS phosphors—I. Spectrum shift during decay and with excitation intensity

Abstract The measurements of spectrum shift during decay and with excitation intensity are made for the broad-band luminescences in ZnS phosphors due to Ib activator and IIIb or VIIb coactivator, in order to investigate the luminescence mechanism. The Green-Cu Blue-Ag luminescences show remarkable spectrum shifts; namely, the emission peak shifts to lower energies during decay and also with decreasing excitation intensity. It is concluded that these luminescences are due to the so-called donor-acceptor pair emission mechanism, assuming that the donor and acceptor states involved are created, respectively, by the coactivator and activator. The self-activated luminescence shows a gradual spectrum shift at liquid helium temperature, although it shows a somewhat irregular shift at liquid nitrogen temperature. It seems that one has to assume the pair emission mechanism also for this luminescence. The Blue-Cu, Red-Cu and Red-Cu.In luminescences show no spectrum shifts. It is concluded, together with the knowledge already obtained from other measurements, that the transitions for these luminescences occur between two localized levels confined within the associated centers.

[1]  S. Shionoya,et al.  Mechanism of broad-band luminescences in ZnS phosphors—II. Characteristics of pair emission type luminescences , 1968 .

[2]  D. G. Thomas,et al.  Kinetics of Radiative Recombination at Randomly Distributed Donors and Acceptors , 1965 .

[3]  P. H. Kasai,et al.  Electron Paramagnetic Resonance Studies of the ZnS-A and -B Centers , 1962 .

[4]  M. Aven,et al.  Fluorescent Emission Spectra in II – VI Compounds , 1965 .

[5]  S. Shionoya,et al.  Nature of Luminescence Transitions in ZnS Crvstals , 1964 .

[6]  S. Shionoya,et al.  Effect of pressure on the luminescence of zinc sulphide phosphors , 1966 .

[7]  D. G. Thomas,et al.  Pair Spectra and "Edge" Emission in Gallium Phosphide , 1964 .

[8]  R. Miller,et al.  Photoluminescene and Pair Spectrum in Boron Phosphide , 1966 .

[9]  S. Shionoya,et al.  Polarization of the Green-Copper Luminescence in Hexagonal ZnS Single Crystal , 1965 .

[10]  S. Shionoya,et al.  Nature of the Self-Activated Blue Luminescence Center in Cubic ZnS: Cl Single Crystals , 1964 .

[11]  F. Williams,et al.  Activator Systems in Zinc Sulfide Phosphors , 1956 .

[12]  Shionoya Shigeo,et al.  Decay characteristics of luminescence in ZnS phosphors by pulse light excitation , 1965 .

[13]  E. F. Apple,et al.  Associated Donor‐Acceptor Luminescent Centers in Zinc Sulfide Phosphors , 1959 .

[14]  S. Shionoya,et al.  Nature of the Green-Copper Luminescence Transition in ZnS as Elucidated by the Measurements of Time-Resolved Spectrum , 1966 .

[15]  H. Kukimoto,et al.  Infrared absorption due to donor states in ZnS crystals , 1968 .

[16]  S. Shionoya,et al.  Nature of the red-copper luminescence centre in ZnS crystals as elucidated by polarization measurements , 1966 .

[17]  F. Williams.  Theory of the energy levels of donor-acceptor pairs , 1960 .

[18]  S. Shionoya,et al.  Optical Symmetry of the Self-Activated Luminescence Center in ZnS Single Crystal , 1963 .

[19]  S. Shionoya,et al.  Polarization of the Self-Activated Luminescence in ZnS:Al Crystals , 1968 .

[20]  D. G. Thomas,et al.  Pair Spectra in GaP , 1963 .