Publication date: 15th December 2025
Spin interactions have emerged as fundamental in organic photovoltaics.[1,2] In this framework, chiral molecules offer an exciting route to control the spin degree of freedom via the chirality-induced spin selectivity (CISS) effect.[3] Recent breakthroughs have enabled the direct detection of CISS in electron donor-acceptor dyads.[4] These studies show that CISS governs the spin dynamics of photoinduced charge transfer through chiral bridges at the molecular level. Understanding the molecular origin of CISS and identifying its key molecular parameters are now pressing priorities.[5,6]
Here, we present new systems consisting of a thiabridged[4]helicene donor covalently linked to a perylenediimide (PDI) acceptor through bridges of variable length. Transient absorption and time-resolved electron paramagnetic resonance (TREPR) spectroscopies reveal that the spin selectivity of charge transfer and triplet formation pathways strongly depends on the bridge design. Orientation-dependent TREPR experiments of the longer chiral dyad and its achiral analogue disclose the generation of distinct spin-polarized radical pair signals. Complementary theoretical simulations clarify the molecular origin of the CISS effect and show that the electron motion through the chiral bridge is essential for its observation.
These results add another piece to the puzzle of chirality in donor-acceptor dyads, with the final aim of exploiting CISS to control electron spin states for applications in photovoltaics and quantum information science.
AP acknowledges financial support from the Italian Ministry of University and Research through the Fondo Italiano per la Scienza project SPIROχ (FIS-2023-01975).
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.