Programmable Interfacial Energy Alignment in Plasmonic Metal-Organic Frameworks for Selective Molecular Probing on Complex Heterogeneous Surfaces

Abstract

In situ identification and spatially resolved analysis of multicomponent species on complex heterogeneous surfaces remain formidable challenges in surface science, advanced manufacturing, and cultural heritage conservation. Although surface-enhanced Raman scattering (SERS) provides highly sensitive molecular fingerprints, existing platforms often struggle to simultaneously achieve robust interfacial contact and discriminable responses on rough, porous, and compositionally heterogeneous solids. Here, we report a programmable interfacial energy-alignment strategy by integrating a core–shell plasmonic metal-organic framework (MOF) heterojunction, Fe₃O₄@SiO₂@UiO-66(X)@Ag triangular nanoplates (Ag TNs), into an injectable poly(vinyl alcohol) (PVA) microgel matrix to construct a self-adaptive SERS chip. The microgel fills surface asperities and establishes semipermeable conformal contact. Upon dehydration, it locally densifies interfacial nanogaps and reconstructs hotspot networks, thereby promoting more effective interfacial coupling within accessible pores and cracks while improving signal stability and reproducibility. Meanwhile, ligand engineering of UiO-66(X) modulates the interfacial electronic structure and favors phase-dependent charge-transfer-assisted enhancement, whereas tuning the tip sharpness of Ag TNs regulates localized surface plasmon resonance (LSPR) coupling under different excitation wavelengths. Excitation- and ligand-controlled SERS experiments, together with density functional theory calculations, provide an electronic-structure rationale for the observed preferential responses and support the involvement of cooperative electromagnetic and charge-transfer-assisted enhancement contributions. As a result, the chip enables phase-resolved identification and spatial mapping of corrosion products in model multilayer systems, as well as low-disturbance in situ analysis and interval-based corrosion-state estimation of excavated bronze artifacts. This work provides a general materials-design framework for programmable interfacial energy-level regulation toward molecular sensing and chemical imaging on complex solid surfaces.

Keywords

complex heterogeneous surfaces / core–shell plasmonic heterojunction / in situ molecular identification / surface-enhanced Raman scattering (SERS) / programmable energy-level alignment

References

[1] P. Verma, “Tip-Enhanced Raman Spectroscopy: Technique and Recent Advances,” Chemical Reviews 117 (2017): 6447–6466.

[2] G. H. Kim, J. Son, and J. M. Nam, “Advances, Challenges, and Opportunities in Plasmonic Nanogap-Enhanced Raman Scattering With Nanoparticles,” ACS Nano 19 (2025): 2992–3007.

[3] Y. Liu, M. Pharr, and G. A. Salvatore, “Lab-on-Skin: A Review of Flexible and Stretchable Electronics for Wearable Health Monitoring,” ACS Nano 11 (2017): 9614–9635.

[4] G. Zhou, P. Li, C. Zhao, X. Guo, R. Dong, and L. Yang, “Insights of Surface-Enhanced Raman Spectroscopy Detection by Guiding Molecules Into Nanostructures to Activate Hot Spots,” Analytical Chemistry 97 (2025): 5612–5623.

[5] B. R. Lutz, C. E. Dentinger, L. N. Nguyen, et al., “Spectral Analysis of Multiplex Raman Probe Signatures,” ACS Nano 2 (2008): 2306–2314.

[6] T. Itoh, M. Procházka, Z. C. Dong, et al., “Toward a New Era of SERS and TERS at the Nanometer Scale: From Fundamentals to Innovative Applications,” Chemical Reviews 123 (2023): 1552–1634.

[7] M. Leona, P. Decuzzi, T. A. Kubic, G. Gates, and J. R. Lombardi, “Nondestructive Identification of Natural and Synthetic Organic Colorants in Works of Art by Surface Enhanced Raman Scattering,” Analytical Chemistry 83 (2011): 3990–3993.

[8] M. Aucouturier and E. Darque-Ceretti, “The Surface of Cultural Heritage Artefacts: Physicochemical Investigations for Their Knowledge and Their Conservation,” Chemical Society Reviews 36 (2007): 1605–1621.

[9] A. Arafat, M. Na'es, V. Kantarelou, et al., “Combined In Situ Micro-XRF, LIBS and SEM-EDS Analysis of Base Metal and Corrosion Products for Islamic Copper Alloyed Artefacts From Umm Qais Museum, Jordan,” Journal of Cultural Heritage 14 (2013): 261–269.

[10] P. Silveira and T. Falcade, “Applications of Energy Dispersive X-Ray Fluorescence Technique in Metallic Cultural Heritage Studies,” Journal of Cultural Heritage 57 (2022): 243–255.

[11] W. Liu, M. Li, N. Wu, S. Liu, and J. Chen, “A New Application of Fiber Optics Reflection Spectroscopy (FORS): Identification of “Bronze Disease” Induced Corrosion Products on Ancient Bronzes,” Journal of Cultural Heritage 49 (2021): 19–27.

[12] G. M. Ingo, E. Angelini, T. De Caro, G. Bultrini, and A. Mezzi, “Combined Use of XPS and SEM+EDS for the Study of Surface Microchemical Structure of Archaeological Bronze Roman Mirrors,” Surface and Interface Analysis 36 (2004): 871–875.

[13] J. Langer, D. Jimenez De Aberasturi, J. Aizpurua, et al., “Present and Future of Surface-Enhanced Raman Scattering,” ACS Nano 14 (2020): 28–117.

[14] J. Chen, Y. Huang, P. Kannan, et al., “Flexible and Adhesive Surface Enhance Raman Scattering Active Tape for Rapid Detection of Pesticide Residues in Fruits and Vegetables,” Analytical Chemistry 88 (2016): 2149–2155.

[15] S. Park, J. Lee, and H. Ko, “Transparent and Flexible Surface-Enhanced Raman Scattering (SERS) Sensors Based on Gold Nanostar Arrays Embedded in Silicon Rubber Film,” ACS Applied Materials & Interfaces 9 (2017): 44088–44095.

[16] A. Ștefăncu, S. Lee, L. Zhu, et al., “Fermi Level Equilibration at the Metal-Molecule Interface in Plasmonic Systems,” Nano Letters 21 (2021): 6592–6599.

[17] J. Ye, R. Arul, M. K. Nieuwoudt, et al., “Understanding the Chemical Mechanism behind Photoinduced Enhanced Raman Spectroscopy,” Journal of Physical Chemistry Letters 14 (2023): 4607–4616.

[18] K. Hendrickx, D. E. P. Vanpoucke, K. Leus, et al., “Understanding Intrinsic Light Absorption Properties of UiO-66 Frameworks: A Combined Theoretical and Experimental Study,” Inorganic Chemistry 54 (2015): 10701–10710.

[19] M. A. Syzgantseva, N. F. Stepanov, and O. A. Syzgantseva, “Band Alignment as the Method for Modifying Electronic Structure of Metal−Organic Frameworks,” ACS Applied Materials & Interfaces 12 (2020): 17611–17619.

[20] B. J. Wiley, S. H. Im, Z. Y. Li, J. McLellan, A. Siekkinen, and Y. Xia, “Maneuvering the Surface Plasmon Resonance of Silver Nanostructures Through Shape-Controlled Synthesis,” The Journal of Physical Chemistry B 110 (2006): 15666–15675.

[21] H. Chen, C. Liu, W. Guo, et al., “Functionalized UiO-66 (Ce) for Photocatalytic Organic Transformation: The Role of Active Sites Modulated by Ligand Functionalization,” Catalysis Science & Technology 12 (2022): 1812–1823.

[22] L. Robbiola, J. M. Blengino, and C. Fiaud, “Morphology and Mechanisms of Formation of Natural Patinas on Archaeological Cu–Sn Alloys,” Corrosion Science 40 (1998): 2083–2111.

[23] J. Wu, N. Li, and W. Luo, “Corrosion Mechanisms and Conservation Strategies for Marine Recovered Bronze Artifacts: Insights From the Nanhai No. 1 Shipwreck,” Journal of Maritime Archaeology 19 (2024): 351–375.

[24] J. R. Lombardi and R. L. Birke, “A Unified View of Surface-Enhanced Raman Scattering,” Accounts of Chemical Research 42 (2009): 734–742.

[25] S. M. Morton and L. Jensen, “Understanding the Molecule−Surface Chemical Coupling in SERS,” Journal of the American Chemical Society 131 (2009): 4090–4098.

[26] D. P. Bui, M. T. Pham, H. H. Tran, T. D. Nguyen, T. M. Cao, and V. V. Pham, “Revisiting the Key Optical and Electrical Characteristics in Reporting the Photocatalysis of Semiconductors,” ACS Omega 6 (2021): 27379–27386.

[27] G. Kresse and J. Furthmüller, “Efficient Iterative Schemes for Ab Initio Total-Energy Calculations Using a Plane-Wave Basis Set,” Physical Review B 54 (1996): 11169–11186.

[28] S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, “A Consistent and Accurate Ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) for the 94 Elements H-Pu,” The Journal of Chemical Physics 132 (2010): 154104.

[29] V. Wang, N. Xu, J. C. Liu, G. Tang, and W.-T. Geng, “VASPKIT: A User-Friendly Interface Facilitating High-Throughput Computing and Analysis Using VASP Code,” Computer Physics Communications 267 (2021): 108033.

[30] W. Ye, H. Wang, J. Shen, et al., “Aggregation of Graphene Oxide and Its Environmental Implications in the Aquatic Environment,” Chinese Chemical Letters 34 (2023): 107327.

[31] W. Yuan, K. Jiao, H. Yuan, et al., “Metal–Organic Frameworks/Heterojunction Structures for Surface-Enhanced Raman Scattering With Enhanced Sensitivity and Tailorability,” ACS Applied Materials & Interfaces 16 (2024): 26374–26385.

[32] Y. Gui, K. Luo, W. Chen, N. Cai, L. You, and J. Li, “Metal–Organic Framework-Based SERS Substrates With Enrichment and Sieving Capability for Trace Detection of Small-Molecule Biomarkers in Serum,” Microchemical Journal 218 (2025): 115526.

[33] M. Sun, C. Zeng, C. Gao, et al., “Medical Sociology,” Journal of Molecular Structure 1311 (2024): 138345.

[34] H. L. Ding, Y. X. Zhang, S. Wang, J. M. Xu, S. C. Xu, and G. H. Li, “Fe₃O₄@SiO₂ Core/Shell Nanoparticles: The Silica Coating Regulations With a Single Core for Different Core Sizes and Shell Thicknesses,” Chemistry of Materials 24 (2012): 4572–4580.

[35] C. R. Lin, O. S. Ivanova, I. S. Edelman, et al., “Carbon Double Coated Fe₃O₄@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption,” Nanomaterials 12 (2022): 376.

[36] H. Li, P. Merkl, J. Sommertune, T. Thersleff, and G. A. Sotiriou, “SERS Hotspot Engineering by Aerosol Self-Assembly of Plasmonic Ag Nanoaggregates With Tunable Interparticle Distance,” Advanced Science 9 (2022): 2201133.

[37] M. Sun, C. Zeng, and C. Gao, et-al., “Dicyanovinyl-Modified Small-Molecular Monophenyl Derivative for Dual-Channel Fluorescence Recognition of Acid and Aliphatic Primary Amine Regulated by Intramolecular Charge Transfer: Synthesis, Stimuli-Response and LED,” Journal of Molecular Structure 1311 (2024): 138481.

[38] E. Chung, J. Jeon, J. Yu, C. Lee, and J. Choo, “Surface-Enhanced Raman Scattering Aptasensor for Ultrasensitive Trace Analysis of Bisphenol A,” Biosensors and Bioelectronics 64 (2015): 560–565.

[39] P. Kambhampati, C. M. Child, M. C. Foster, and A. Campion, “On the Chemical Mechanism of Surface Enhanced Raman Scattering: Experiment and Theory,” Journal of Chemical Physics 108 (1998): 5013–5026.

[40] N. Valley, N. Greeneltch, R. P. Van Duyne, and G. C. Schatz, “A Look at the Origin and Magnitude of the Chemical Contribution to the Enhancement Mechanism of Surface-Enhanced Raman Spectroscopy (SERS): Theory and Experiment,” The Journal of Physical Chemistry Letters 4 (2013): 2599–2604.

[41] Q. H. Guo, C. J. Zhang, C. Wei, et al., “Controlling Dynamic SERS Hot Spots on a Monolayer Film of Fe₃O₄@Au Nanoparticles by a Magnetic Field,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 152 (2016): 336–342.

[42] X. Liang, H. J. Zhong, H. Ding, et al., “Hydrogel Microspheres Empowering Organ-on-a-Chip Systems: Innovations and Applications,” Polymers 16 (2024): 2435.

[43] D. Cialla-May, A. Bonifacio, A. Markin, et al., “Recent Advances of Surface Enhanced Raman Spectroscopy (SERS) in Optical Biosensing,” TrAC Trends in Analytical Chemistry 181 (2024): 117990.

[44] Y. Jing, R. Wang, Q. Wang, et al., “An Overview of Surface-Enhanced Raman Scattering Substrates by Pulsed Laser Deposition Technique: Fundamentals and Applications,” Advanced Composites and Hybrid Materials 4 (2021): 885–905.

[45] D. Shin, S. Lee, D. R. Kim, et al., “Nanomaterials for Energy and Sensor Applications,” Energies 13 (2020): 4753.

[46] L. Burgio and R. J. H. Clark, “Library of FT-Raman Spectra of Pigments, Minerals, Pigment Media and Varnishes, and Supplement to Existing Library of Raman Spectra of Pigments With Visible Excitation,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 57 (2001): 1491–1521.

[47] J. X. Wang, H. Zhang, L. Y. Niu, et al., “Organic Composite Crystal With Persistent Room-Temperature Luminescence above 650 nm by Combining Triplet–Triplet Energy Transfer With Thermally Activated Delayed Fluorescence,” CCS Chemistry 2 (2020): 1391–1398.

[48] B. Bozzini, A. Gianoncelli, C. Mele, A. Siciliano, and L. Mancini, “Electrochemical Reconstruction of a Heavily Corroded Tarentum Hemiobolus Silver Coin: A Study Based on Microfocus X-Ray Computed Microtomography,” Journal of Archaeological Science 52 (2014): 24–30.

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