Nanowire-based AFM-IR microscopy: Unveiling chemical structure at sub-10-nm resolution with silver nanowire-functionalized AFM probes

• 成果类型: Article
• 署名作者: Fujita, Yasuhiko; Takahashi, Mariko; Taemaitree, Farsai; Uji-i, Hiroshi; Watanabe, Hirohmi
• 署名单位: National Institute of Advanced Industrial Science & Technology (AIST); Hokkaido University; Hokkaido University; KU Leuven; Kyoto University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2528122123
• 发表日期: 2026-05-05
• 页码: e2528122123
• 关键词: atomic force microscopy; near-field spectroscopy; infrared spectroscopy; noble metal nanowires; Fabry-P & eacute; rot resonances; atomic-force microscopy; infrared-spectroscopy; PHOTOINDUCED FORCE; metamaterials; GROWTH

摘要

Atomic force microscopy-based infrared (AFM-IR) microscopy has emerged as a powerful tool for nanoscale chemical imaging, combining the topographical precision of AFM with the molecular specificity of IR spectroscopy. However, its performance is still limited by conventional metal-coated AFM probes, which provide only modest near-field enhancement, ultimately restricting both spatial resolution and chemical sensitivity. In this work, we present a nanowire-based AFM-IR approach that overcomes these limitations by introducing a probe design: Chemically synthesized noble metal nanowires are affixed to the tip of a standard AFM cantilever. These nanowires support Fabry-P & eacute;rot resonances, functioning as mid-IR antennas that generate strongly confined optical near-field, thereby enhancing spatial resolution and sensitivity. The probe design also enables stable AFM-IR operation on both hard and soft materials. We demonstrate significantly improved imaging and spectroscopic performance, achieving spatial resolution below 10 nm and sensitivity at the submonolayer level. These findings establish nanowire-based AFM-IR microscopy as a highly promising platform for superresolution vibrational spectroscopy, with broad applications ranging from soft matter and two-dimensional materials to biomolecular analysis.