Ultrafast broadband sensitive magneto-chiroptical microscopy to track the consequences of symmetry breaking in solution-processable semiconductors

forthcoming

Chiral solution-processable semiconductors are a new class of materials that could revolutionize optoelectronics by enabling circularly polarized light (CPL) emission and spin control without external magnetic fields at room temperature. This could enhance the efficiency of displays, solar cells, holography, cryptography, and biomedical imaging, while opening new possibilities in quantum information processing. However, current trial-and-error approaches, limited by the absence of suitable techniques to probe mechanisms, prevent systematic breakthroughs in designing chiral materials with strong CPL emission and spin polarization. MACHIRO will overcome these limitations. We will develop the first ultrafast broadband magneto-chiroptical microscope to map the Stokes vector of light polarization emitted from chiral materials with diffraction-limited spatial and femtosecond-temporal resolution. This will enable us to directly track the interplay between charge, spin, and light polarization in time and space, to mechanistically understand how CPL and spin polarization arise from structural chirality imprint on the excited state. We will use this new tool to study a range of i) heavy-element containing chiral halide perovskite semiconductors, as well as ii) purely molecular twisted materials with much less spin orbit coupling. We will systematically vary dimensionality (3D bulk to 0D quantum dots), hierarchical level of chirality, helical pitch and addition magnetic impurities, while always monitoring the role of local disorder through mapping. Thus, we will identify dominant loss channels and arrive at a unified mechanism of how light and spin polarization are connected. Finally, we will integrate insights across all materials, establishing universal design rules for using chirality to control spin and light simultaneously, enabling next-generation solution-processable spin-optoelectronic technologies with unprecedented energy efficiency.