Magnetic Circularly Polarized Luminescence of Organic Compounds

Abstract

Achiral purely organic molecules can show selectivity towards circularly polarized light in emission in the presence of a magnetic field. This phenomenon is called magnetic circularly polarized luminescence (MCPL). Recently a few examples of MCPL from organic molecules have appeared in the literature. Through this technique, interesting photophysical information can be inferred and, moreover, a few technological applications can be devised based on this principle. This short review has the purpose to give a general introduction to this recent field of research and some critical insights on the reported examples.

Magneto-chiral dichroism of chiral lanthanide complexes

“…In that case, a chiral system shows emission of CPL upon application of a nonpolarized excitation, even if this phenomenon is now also studied under a magnetic field. 12–14 MChA refers to a modulation of the absorption or emission intensity of light collinear to an applied magnetic field without generation of CPL.…”

Enhancement of circularly polarized electroluminescence via reflection reversal under a magnetic field

“…In recent years, external static magnetic fields have garnered significant attention as a physical bias to induce circularly polarised signals in the photoexcited states of achiral and racemic organic, organic–inorganic, or inorganic luminescent materials. 30–45 In this context, we have succeeded in generating full-colour red-green-blue-yellow (RGBY) CPEL under a magnetic field from organic light-emitting diodes (OLEDs) incorporated with optically inactive phosphorescent iridium( iii ) luminophores in the EML. That is, the application of an external magnetic field allows us to develop phosphorescent CP-OLEDs without any chiral phosphors, namely, magnetic CP-OLED (MCP-OLEDs).…”

Magneto-optical Properties of Chiral Co2Ln and Co3Ln2 (Ln = Dy and Er) Clusters

“…To evaluate the magneto-optical effects of ( R )-Co 2 Er and ( R )-Co 3 Er 2 , we calculated the g MCD values using the formula g MCD = 2­{[ε + ( B ) – ε + (− B )]/[(ε + ( B ) + ε + (− B )]}, simplified to g MCD = Δε/ε. , Additionally, we normalized the magnetic field strength using the formula g Nor = g / B ( B = 1.6 T). , It should be noted that when circularly polarized light passes through an absorbing medium, the absorption between left and right circularly polarized light differs (ε L ≠ ε R ), with the CD representing the difference Δε = ε L – ε R . The ε value is derived from the absorption spectrum ε = [(ε + ( B ) + ε + (− B )]/2 at the same concentration as that used to measure the MCD spectrum.…”