Size-dependent SERS property of red phosphorous in the transition from bulk to nanosheet and its application in immunosensing

Attributed to their structure-dependent chemical enhancement capability and perfect biocompatibility, semiconductors have attracted significant concern in surface enhanced Raman scattering (SERS)-based immunoassay. By continually adjusting the size of red phosphorus (RP) in the transition process from bulk to nanosheet, we investigated in detail about the improvement of high-efficient charge transfer (CT) resonance dependent on the perfect energy level matching within the substrate-molecule combination. The nano-sized RP has achieved an impressive three-fold enhancement in SERS intensity in comparison to the RP nanosheet. Furthermore, the RPbased immunosubstrate was combined with MoS2 nanoflowers-based immunoprobe to construct a sandwich immunostructure for the accurate and efficient diagnostics of cancer marker prostate-specific antigen. A limit of detection as low as 3.99 x 10-10 M was obtained in the SERS-based immunoassay with reliable specificity. This study presents an innovative approach to promote the SERS performance of semiconductors, which may find potential biological applications in the early screening of cancer.

Automated summary

This study investigates the size-dependent enhancement of charge transfer resonance in semiconductors by adjusting the size of red phosphorus. The nano-sized red phosphorus achieves a three-fold enhancement in surface enhanced Raman scattering (SERS) intensity compared to nanosheets, making it a potential tool for accurate and efficient cancer marker diagnostics.