Spin selective devices and organic spintronics from chiral lanthanide-based systems (Spin X-LaB)

Chiral induced spin selectivity (CISS) effect is the ability of chiral semiconducting materials to selectively conduct electrons with a preferential spin, depending on the handedness of the material itself. This phenomenon has several major implications ranging from biological systems to electronic devices. CISS has been demonstrated in diverse molecular systems such as DNA monolayers, supramolecular aggregates, semiconducting polymers, proteins, metal oxides and perovskites crystals. Several parameters are proposed to play a major or significant role in regulating the CISS of chiral materials. Among those we may identify: chiroptical activity, paramagnetism and the related anisotropy of the magnetic susceptibility tensor, and the presence of energy transfer and donor-acceptor dynamics. Despite the relevance of such parameters have been reported previously, they have not been systematically investigated so far. Despite chiral Lanthanide (Ln) complexes have never been explored in this context, they would offer a privileged scaffold to investigate the effects of such parameters. All the above-mentioned properties can be effectively and independently controlled by the choice of the Ln centre and the ligands. Therefore, systematically modifying ligands (e.g. with electron donating/withdrawing group) or lanthanide core, individual parameters can be addressed. In particular, chiral Ln complexes are widely investigated in the field of circularly polarized luminescence (CPL) as they can emit light with a degree of circular polarization which is almost precluded to isolated organic molecules. As the relationship between chiroptical properties (such as circular dichroism and CPL) and CISS effects is expected to be strong, Ln chiral complexes are interesting candidates. Another advantage is that, unlike many organic molecules, (chiro)optical properties of Ln chiral complexes are mainly local; therefore, they do not depend on aggregation modes. This will allow us to prepare thin films featuring the required characteristics for CISS studies without significantly affecting the desired properties. The project will contribute to the fundamental understanding of the role played by the above-mentioned parameters and will establish chiral Ln complexes as a new and versatile class of CISS materials. As a practical outcome of the project, we will build a proof-of-concept spin-OLED, exploiting a chiral layer as the spin filter and a Ln complex as the emitter