Luminescence Study of CaF2.5Al2O3 doped with Tb3 + and Pb2+ Activators

Abstract

Wide-band-gap fluoride CaF2 provide attractive hosts for those rare earth (RE) ions that are capable of
producing fast and efficient emissions under ionizing irradiation. The quality of calcium difluoride (fluorite, CaF2) as an
optical material has been greatly improved over the past years following a demand for highest quality materials used as lens
and window material in ultraviolet laser lithography systems. CaF2:Eu have been investigated as efficient luminescent
materials with potential applications in solid state lighting, fiber amplifiers, solid state lasers, and radiation detection
CaF2:Eu2+ is one of the earliest known thermoluminescent materials and was among the earliest used for TL dosimetry. Wet
chemical synthesis and combustion synthesis were used to prepare CaF2.5Al2O3. The X-ray diffraction pattern of the powder
synthesized by combustion synthesis of aluminium nitrate and calcium fluoride in the mole ratio of 1:10:26.66. All the peaks
are well indexed to CaF2.5Al2O3 phase (Acta Cryst. 6 (1953) 363). Luminescence studies have been carried out frequently for
CaF2 but there are no data on CaF2.5Al2O3. The excitation spectra for Tb3+consists of two peaks ranging from 200 to 310 nm
with a maximum at about 235 nm, corresponding to 4f8
– 4f7
5d1
transition for the prominent emission at 543nm. Similarly for
Pb2+ the emission is around 370nm for the excitation of 254nm