Upconversion photoluminescence of lanthanide complexes
Lanthanide-doped upconversion materials have great potential for applications such as fluorescence labels for in vitro bioimaging, as lighting sources in optical devices or as up-shifting layers in solar cells. These materials absorb light in the near infrared (NIR) spectral region (typically at ca. 980 nm) and emit light in the visible range. The structure of the luminescence spectrum strongly depends on the composition of the upconversion material as well as on the excitation intensity. The FluoTime 300 spectrometer can achieve very high spectral resolution along with outstanding stray light rejection when equipped with double monochromators in both excitation and emission pathways. This configuration is therefore well suited to measure the rather weak upconversion luminescence from these highly scattering samples. The upconversion luminescence kinetics of lanthanide-doped materials can range from nanoseconds to milliseconds. Thus the FluoTime 300 spectrometer is ideally suited to study these materials as it can cover time spans from a few picoseconds to several seconds by using either Time-Correlated Single Photon Counting (TCSPC) or Multi-Channel Scaling (MCS).