Abstract of Publication No. 396
We present and analyse high-resolution absorption, luminescence and
upconversion-luminescence spectra of Cs2GeF6: 2% Re4+.
The crystals of Cs2GeF6: 2% Re4+ were
grown from solution. Upon excitation around 11000 cm–1 in the
near infrared, visible upconversion luminescence around 17000 cm–1
is observed. On increasing the temperature from 15 K to room temperature
the integrated upconversion luminescence intensity decreases to 2%. This
is attributed to the decreasing absorption cross-section at the
monochromatic laser-excitation energy. The upconversion excitation spectra
and the results obtained from time-dependent measurements indicate a
dominant energy-transfer upconversion mechanism.