Ultrasensitive and smart trace detection via interface-enhanced multi-phonon resonance Raman scattering

Trace detection technology has important applications in fields such as biomedicine, food safety, and environmental monitoring. However, it currently faces challenges including insufficient sensitivity, low efficiency, and a need for improved personalized services, which seriously hinder the in-depth development and widespread application of trace detection technology. Herein, a metal/semiconductor heterojunction was designed and constructed. The synergistic effects of interfacial charge transfer and interfacial passivation of anion vacancy defect states density were revealed to significantly enhance the intensity of multi-phonon resonance Raman scattering (MRRS) of the semiconductor with an enhancement factor of up to 1.4 × 10⁹. A MRRS detection platform was developed to achieve a detection limit of 8.5 aM for let-7a and a relatively wide linear range from 50 aM to 100 nM. Compared to conventional semiconductor detection platforms, the heterojunction probes reduced the detection limit by three orders of magnitude, and expanded the linear range by five orders of magnitude. Furthermore, the enhanced synergistic effect at the heterojunction interface directly boosts the MRRS signal intensity, significantly lowering the detection limit, and broadening the linear range. To further improve detection efficiency and user experience, this technology was combined with smartphone intelligent analysis software, allowing for rapid reading and intelligent analysis of MRRS data from serum sample, which enhances the speed and accuracy of data processing. This work not only offers a new, ultrasensitive approach to develop trace detection technology, but also makes significant strides in improving personalized services and promoting the advancement of telemedicine.