Probing the chirality and optical activity of organic molecules through the anisotropic photoluminescence of porous silicon

In this study, we investigate the potential of using the unique anisotropic photoluminescence (PL) properties of porous silicon (PSi) to detect the chirality and optical activity of organic molecules. We systematically measure the polarization and intensity of the anisotropic PL response of PSi to chiral and spiropyran molecules with different chemical structures to determine the chiral resolution and optical activity of these molecules. Our results indicate that compared with the use of a laser excitation source (method I), the use of an improved light-emitting diode light source (method II) provides a higher resolution for chiral structures and considerably improved the discrimination of chiral molecules. The method developed in this study (method II) can also be used to determine the concentration of spiropyran molecules. The results of this study suggest that using the anisotropic PL properties of PSi for detecting the chirality and optical activity of organic molecules is a reliable and sensitive method.