Influence of Ce3+ Concentration on the Thermal Stability and Charge-Trapping Dynamics in the Green Emitting Phosphor CaSc2O4:Ce3+
Artikel i vetenskaplig tidskrift, 2017

The influence of the Ce3+ concentration on the excitation and emission characteristics, thermal stability, and charge-trapping-detrapping dynamics, of the green-emitting phosphor Ce3+ doped calcium scandium oxide (CaSc2O4) with very dilute Ce3+ substitutions (0.5, 1.0, and 1.5%), has been investigated using optical spectroscopy techniques. The diffuse reflectance and excitation spectra are found to exhibit a nonsystematic behavior with varying Ce3+ concentration, mainly linked to spectral band-overlap, whereas the emission spectra display only minor changes with varying Ce3+ concentration, suggesting that the local structural coordination of the Ce3+ dopants remains the same for different Ce3+ dopant levels. The major impact of Ce3+ concentration is seen on the thermal quenching temperature, which is found to be as high as T-50% approximate to 600 K for the most dilute Ce3+ doping (0.5%), followed by T-50% approximate to 530 K for 1.0% doping and T-50% approximate to 500 K for 1.5% doping, respectively. The materials are found to display a red-shift of the emitted light from 518 to 535 nm with increasing temperature from T = 80 K to T = 800 K, for all Ce3+ dopant levels. Thermoluminescence glow curves provide evidence for five charge-trapping defects, which are found to exhibit different charge-trapping dynamics for excitation into different 5d levels. It is argued that the three deeper traps can be filled by athermal tunneling of charges from the Ce3+ 5d(1) level, while the two shallower traps can only be filled when the charges move through the conduction band of the material.

Författare

Suchinder Sharma

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

M. Bettinelli

I. Carrasco

Maths Karlsson

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 121 41 23096-23103

Ämneskategorier

Atom- och molekylfysik och optik

DOI

10.1021/acs.jpcc.7b03263

Mer information

Skapat

2017-11-16