Strong increase the photoluminescence of Dy3+ doped germanate compounds by optimizing the synthesis conditions

Abstract

The aim of the present study was to investigate the influence of synthesis conditions (temperature and synthesis time) and consequently the change in particle size and shape, their size distribution, degree of agglomeration and the degree of crystallinity on the emission intensity of three different germanates Li 2 CaGeO 4 , Ca 2 GeO 4 and Ca 5 Ge 3 O 11 doped by 1at% Dy 3+ . The analysis showed that the emission intensities of Li 2 CaGeO 4 , Ca 2 GeO 4 and Ca 5 Ge 3 O 11 doped by 1at% Dy 3+ increase 4, 10 and 3 times only as a result of optimizing the synthesis conditions. Studies have shown definitely that the dominant factor for this strong increase of the emission intensity is the increase of the degree of crystallinity. The presence of agglomeration in high temperature synthesis (in the case of Ca 2 GeO 4 ) strongly reduces the emission intensity. The sizes and shape of the particles, as well as their size distribution for the three investigated compounds are of secondary importance for the emission intensity. • Dysprosium doped powder Li 2 CaGeO 4 , Ca 2 GeO 4 and Ca 5 Ge 3 O 11 samples are prepared. • Different thermal treatment conditions are used. • XRD, SEM images and particle size distribution are presented. • Emission and excitation spectra of powder samples are presented. • Several relations between the synthesis regime and spectra intensity are obtained.