Thermoluminescence and photoluminescence study of KY3F10:Ho3+ commercial phosphor powder

Abstract

Thermoluminescence (TL) and photoluminescence (PL) properties of KY3F10:Ho3+ phosphor powder is reported. The TL measurements were carried out for different heating rates and for various durations of UV exposure. The TL intensity increases with the duration of UV exposure up to 20 min and then decreases. A decrease of the glow peak height was observed for the glow curves with an increasing heating rate. The area under the TL-time plot is calculated for each heating rate at a constant UV dose and it is found to be constant and independent of the heating rate. It is found that the observed decrement in intensity of each glow curve following an increment in the heating rate is not attributed to the thermal quenching effect. Important TL kinetic parameters namely, the activation energy (E) and the frequency factor (s) were calculated using a variable heating rate (VHR) method. The glow peaks obey first order kinetics. PL emission spectra were also investigated at four main excitation wavelengths; namely, 362, 416, 454 and 486 nm. Green emission at 540 nm and faint red emission at 750 nm were observed for all the excitations. The green emission at 540 nm is ascribed to the 5F4–5I8 and 5S2–5I8 transitions and the faint red emission at 750 nm is due to the 5F4–5I7 and 5S2–5I7 transitions. In addition to the sharp green emission at 540 nm, a broad emission centered at 600 nm was observed for excitation wavelength of 362 nm.