Perovskite Mediated Vibronic Coupling of Semiconducting SERS for Biosensing

Abstract Improving charge transfer efficiency via vibronic coupling is vital to the performance of semiconducting surface‐enhanced Raman spectroscopy (SERS). Previous attempts have focused on defects‐based metastable‐state assisted band structure matching strategy to enhance vibronic coupling. However, defect‐related charge transfer transitions can be easily deteriorated due to enhanced phonon‐assisted relaxation upon continuous laser irradiation. Herein, perovskite‐based steady‐state assisted band structure matching strategy is proposed to enhance vibronic coupling within perovskite‐molecule charge transfer complex, leading to remarkable Raman enhancement up to 5.9 × 10 6 . Particularly, vibronic coupling can be modulated by tuning valence band position and introducing ultrathin Au coating, which allows selective enhancement of molecules with different band structures, including narrow‐bandgap molecules and wide‐bandgap molecules. Importantly, based on intrinsically stable conduction band and valence band states, this system achieves ultrahigh photostability, preserving 91.3% of the original intensity after 50 000 s of irradiation. This system also provides an outstanding tool for trace molecular detection, allowing sensitive and selective identification of 9 types of gastric cancer related aldehydes, which enables distinguishing the breath of gastric cancer patients from healthy controls with a discriminatory accuracy of 81.09%. This study is anticipated to shed new light into the future strategy design of efficient and stable semiconducting SERS.