Surface-enhanced Raman scattering (SERS) as a label-free, non-contact, highly sensitive, and powerful technique has been widely applied in determining bio- and chemical molecules with fingerprint recognitions. 2-dimensional (2D) materials with layered structures, tunable optical properties, good chemical/physical stabilities, and strong charge–transfer interaction with molecules have attracted researchers’ interests. Two-D materials with a large and flat surface area, as well as good biocompatibility have been considered promising candidates in SERS and widely applied in chemical and bio-applications. It is well known that the noble metallic nanostructures with localized surface plasmon effects dominate the SERS performance. The combination of noble metallic nanostructure with 2D materials is becoming a new and attractive research domain. Until now, the SERS substrates combined with 2D materials, such as 2D graphene/metallic NPs, 2D materials@metallic core-shell structures, and metallic structure/2D materials/metallic structure are intensely studied. In this review, we introduce different kinds of fabrication strategies of 2D and 3D SERS substrates combing with 2D materials as well as their applications. We hope this review will help readers to figure out new ideas in designing and fabricating SERS substrates with high SERS performance that could enlarge the applicable domains of SERS.
Understanding chiral dynamic mechanisms (from chirality generation and transfer, and amplification) is crucial for circularly polarized luminescent (CPL) materials. Herein, intrinsically chiral bipyrenyl-based enantiomers, R-5 and S-5, were first synthesized as model compounds to gain a deeper insight into their chiroptical properties and the chirality amplification mechanisms. These enantiomers not only exhibit typical aggregation-induced emission (AIE) with a high solid-state fluorescence efficiency up to 0.66, but also display significant chirality amplification upon aggregation, with amplified |gCD| from 4.73 10-5 (10-7 M) to 7.3410-3 (10-3 M), and |glum| values up to 4.6810-4 in the solid state. Morphological and CP-fs-TA studies reveal that the amplified chiroptical properties stem from helical self-assembly and prolonged excited-state chiral conformational reorganization in aggregates. This work establishes a design strategy for high-performance CPL materials by integrating intrinsic chirality, AIE properties, and dynamic chirality amplification mechanisms.