Surface-enhanced circular dichroism by butterfly frame structure

Circular dichroism (CD) is widely used for the characterization of molecular chirality, protein secondary structure determination, and evaluation of biomolecule stability. However, the inherently weak CD signal of chiral molecules poses considerable challenges for their detection. In this paper, a novel approach employing a butterfly frame structure is proposed to enhance the sensitivity of molecular chirality detection. It is demonstrated that this structure can achieve up to 241-fold CD enhancement. Furthermore, a clear and comprehensive explanation of the mechanisms underlying molecular CD, its distinct components, as well as induced circular dichroism is presented. The proposed mechanism suggests that chiral molecules affect nanostructures, leading to differences in the optical rotation of electric fields, thus inducing CD effects. The hypothesis is verified by calculating the average difference in rotation angle, providing conclusive evidence supporting our proposed mechanism. The results not only reveal insights into the induced CD mechanisms but also suggest a promising approach for enhancing single molecular chirality detection.