Impact of the experimental bandwidth on circularly polarized luminescence measurements of lanthanide complexes: the case of erbium(iii)

This article outlines the synthesis and comprehensive characterization of a pair of Er(iii) enantiomers with controlled helicity. These complexes exhibit a near-infrared circularly polarized luminescence (NIR-CPL) signature with high glum values of +/- 0.66 at 1519 nm at room temperature. However, due to a large number of potential transitions at this temperature owed to the crystal field splitting, the CPL pattern likely results from overlapping of many positive and negative contributions. This study explores how reducing the effective bandwidth affects the CPL spectral analysis. Practical insights are provided for measuring CPL spectra, highlighting the importance of resolving peak positions with opposite signs to accurately determine g(lum) values.