Recently, the Surface-Enhanced Spectroscopy research group from the School of Physics at Southeast University published a perspective review titled "Plasmonic Nanoarrays as SERS Substrates: Advances, Challenges, and Perspectives"in the prestigious international journal Accounts of Chemical Research. The paper summarizes the research progress, technical advantages, and future challenges of the nanoarray approach in the field of surface-enhanced Raman scattering (SERS), with a particular focus on the "programmable nanoarray technology" based on anodic aluminum oxide (AAO) nanotemplates.
Surface-enhanced Raman scattering (SERS) is a molecular spectroscopy technique known for its high sensitivity and chemical specificity. The performance of SERS relies on the manipulation of light by nanostructures, making structural design a core issue in the field. For a long time, mainstream SERS research has primarily been based on chemically synthesized nanoparticles. While this system offers notable advantages such as flexible preparation, rich functionality, and broad applicability, issues like particle aggregation and difficulty in removing surfactants can introduce interfering variables in research scenarios that emphasize reproducibility, interface cleanliness, and mechanistic interpretability.
Compared to chemically synthesized particles, nanoarray SERS substrates represent a relatively niche but distinctive technical route. This method combines physical deposition with nanotemplates to construct clean, ordered, and tunable nanoarrays, providing a new perspective for SERS research:
From a mechanistic research standpoint:
1. Physically deposited nanostructures are more stable, enabling controlled experiments under strong chemical stimuli;
2. The absence of surfactants and ligands on the surface helps suppress additional variables (e.g., molecular co-adsorption, interfacial side reactions, material work function, chemical damping);
3. Flexible designs, such as the "A-B-A nanotrimer," allow for in situ SERS studies of transition metal interfaces while minimizing interference from plasmonic effects.
From a molecular detection standpoint:
1. Selectivity: Nanoarrays can be designed as molecular traps for selective SERS detection;
2. Stability: Arrays possess structurally defined dimensions, ensuring reproducibility across areas, batches, and laboratories;
3. Sensitivity: Uniform polarization orientation of the array units can effectively enhance SERS sensitivity.
Nanoarrays still face certain challenges:
1. Steric effects may limit molecular access to hotspot regions, hindering full utilization of SERS sensitivity;
2. Fabrication of large-area, long-range ordered structures remains difficult, limiting broader application.
Overall, the research team believes that while nanoarrays are not the mainstream approach in SERS research, they offer unique advantages and serve as an important complement to existing systems. They can help advance SERS studies through cross-validation, mechanistic clarification, and continued innovation from diverse perspectives.
The paper’s co-first authors are Southeast University Ph.D. candidates Yao Lei and Chen Shuying. The corresponding authors are Professor Qiu Teng and Professor Hao Qi from Southeast University, along with collaborator Professor Yang from Zhejiang University.
Link: https://doi.org/10.1021/acs.accounts.6c00046
