Research Projects

Spintronics uses spin rather than the charge of electrons to carry and process information. Regulating electron spin requires far less energy (one-thousandth) than driving electrons, making spintronic devices more energy-efficient than traditional microelectronics. Typically, spintronics devices are made from inorganic materials, but matching magnetic properties with the structural properties of inorganic films complicates the device production. This and other challenges drive the interest in exploring organic materials. Organic molecules in spintronic devices do not serve as electron spin polarizers rather a medium to transport electrons with specific spin orientations, also known by chirality-induced spin selectivity (CISS) phenomenon. Recent advances exploiting CISS in various chiral organic molecules, including biomolecules (e.g., DNA, peptides, and proteins) and synthetic chiral compounds (e.g. helicenes), have demonstrated substantial spin-filtering efficiencies, especially when organized in well-defined orientations. However, to date, they have been lacking the performance and mechanistic understanding required for commercial translation. More importantly, they lack structural diversities, alignment controllability and tunable chirality by simpler means. Traditional approaches for alignment involve self-assembled monolayers (SAMs) or supramolecular chiral assemblies on conductive surfaces, which offer some control over molecular orientation. However, these methods face limitations, including complex synthesis, limited molecular compatibility, and challenges in achieving consistent molecular alignment. These issues highlight the need for new materials that combine ease of processability, tunability, and reliable orientation control to enhance spin-filtering performance and enable broader applicability of CISS effect. In this direction, chiral liquid crystals (LCs), such as cholesteric/chiral nematic and chiral columnar LCs have not been touched so far. LCs, a unique phase between crystalline solids and isotropic liquids—known for their inherent alignment capability, self-organization and long-range order are highly desirable in spintronic applications where consistency in order and alignment directly impacts device performance. In chiral nematic LCs, we aim to use light to tune chirality by integrating molecular photoswitches by virtue of change in its helical pitches. These systems will also allow us to switch on/off the chirality with light stimulus by changing helices alignment from standing cholesteric to laying chiral helices. Additionally, we will explore light-responsive chiral nematics capable of reversing helical chirality, providing dual spin polarizers within a single system, which will further validate CISS mechanisms. Light-responsive chiral columnar LCs tuning its charge transport and helical sense will also be explored as part of this project.