Molecular Detection Sensitivity at the Sub-Atto-Molar Limit Using Plasmonic Perovskite Nanoplates

Numerous pioneering studies have reported molecular detection in the limit ranges from μM to pM concentration; however, the beyond-pM limit of detection largely remains elusive. As in many cases, the concentration of the sample target in medical species is ultralow; therefore, highly precise detection of molecules in the femto- to atto- to zepto-molar regime may provide a breakthrough in medical science. We developed a two-dimensional (2D) plasmonic perovskite-based hybrid via an in situ interfacial strategy, which can detect molecules precisely at sub-atto-molar (<10–18 M) concentrations using the surface-enhanced Raman scattering (SERS) technique. The feedback from optical spectroscopic experiments indicated the presence of an extremely strong exciton–plasmon coupling in the CsPbBr3@Au nanoplatelets, resulting in simultaneous electromagnetic enhancement and plasmon-induced charge transfer-mediated chemical enhancement, providing ultralow SERS detection sensitivity. Moreover, density-functional theory calculations as well as finite-difference time-domain (FDTD) simulations were used to determine the detection ability of these nanohybrids in sub-atto-dilute solutions. The ultralow detection sensitivity of plasmonic perovskite nanocrystals may open avenues in clinical, biomedical, and sensor technology.