• chirality
• chiroptical spectroscopy
• europium
• Lanthanides
• OLED
• polarization

Chiral molecules can emit left and right polarized light with different intensities;
this phenomenon is known as circularly polarized luminescence (CPL). CPL can
be observed in photoluminescence and in electroluminescence. In general CPL
spectroscopy can be an interesting tool to investigate the chirality of the excited
state or it can be employed in technological applications such as OLEDs able to
directly emit circularly polarized electroluminescence (CP-OLEDs).
The first part of this work concerns chiral lanthanide complexes, which can emit
CPL with a degree of circular polarization which is almost precluded to non-
aggregated purely organic molecules. In this part, we present a new chiral Eu
complex with highly polarized emission and, a series of CP-OLEDs based on a
lanthanide complex. Following this strategy, the highest polarization degree
reported to date is obtained. Moreover, we discuss and rationalize the factors
affecting the polarization inside a device.
In the second part, we investigate the CPL properties of chiral organic molecules
and we apply CPL spectroscopy as a qualitative analytical tool in pH-dependent
chiroptical switch and to signal the interaction between fluorescent stains and
protein-based matrices used in paintings.