{
  "abstract": "Enhancing the thermoelectric power factor of single-molecule junctions requires simultaneously achieving high electrical conductance and thermopower, which are often mutually constrained. The sharp and asymmetric transmission features produced by Fano resonances offer a promising strategy for mitigating this trade-off. However, quantitative molecular structure–line-shape relationships linking molecular modifications to the resonance valley position and peak-valley energy width remain underexplored. Here, we demonstrate a molecular engineering strategy based on electronically tunable 9-fluorenylidene derivatives to tailor Fano resonance line shapes in single-molecule junctions. Systematic density functional theory and non-equilibrium Green’s function (DFT-NEGF) calculations reveal that substituent-induced variations in local orbital energies, backbone-side-chain coupling and localized-delocalized state detuning control the resonance valley position and the peak-valley energy width. Specifically, the valley position correlates linearly with the energy level of the side-group-localized LUMO, whereas the width is governed by the combined effect of main-side-chain coupling and localized-delocalized state detuning. Together, these two orbital descriptors provide a practical basis for the predictive molecular engineering of Fano resonance line shapes. To experimentally validate this strategy, we synthesized and characterized the designed dicyanomethylene-substituted derivative C -(CN) 2 alongside a control molecule A -O . Electrochemically controlled scanning tunneling microscope break-junction (EC-STM-BJ) measurements confirm the emergence of Fano resonance features near the Fermi level for C -(CN) 2 , in agreement with the DFT-NEGF prediction, whereas no comparable features is observed for A -O. Crucially, statistical single-molecule conductance and thermopower measurements reveal that C -(CN) 2 simultaneously exhibits higher conductance ( G ) and Seebeck coefficient ( S ) than A -O , overcoming the usual trade-off between these two parameters. This synergy effect yields a 97.6% enhancement in thermoelectric power factor ( GS 2 ) relative to control systems. By establishing explicit structure–line-shape–property relationships, this work provides a practical molecular engineering strategy for engineering Fano resonances in single-molecule thermoelectrics.",
  "abstract_shown": true,
  "affiliations": [
    "National Center for Nanoscience and Technology",
    "Institute of Chemistry, Chinese Academy of Sciences",
    "College of Chemistry and Chemical Engineering & Institute of Artificial Intelligence & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, P. R. China.",
    "Nanyang Technological University"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Qianyu Ding"
    },
    {
      "affs": [
        1
      ],
      "name": "Kai Song"
    },
    {
      "affs": [
        1
      ],
      "name": "Weichen Bai",
      "orcid": "0009-0005-0781-9320"
    },
    {
      "affs": [
        2
      ],
      "name": "Mingchen Liang"
    },
    {
      "affs": [
        0
      ],
      "name": "Wei Hao"
    },
    {
      "affs": [
        1
      ],
      "name": "Yaping Zang"
    },
    {
      "affs": [
        2
      ],
      "name": "Junyang Liu"
    },
    {
      "affs": [
        3
      ],
      "name": "Shuzhou Li"
    },
    {
      "affs": [
        0
      ],
      "name": "Jia Zhu"
    },
    {
      "affs": [
        1
      ],
      "name": "Daoben Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fm1z0zxk67msp.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv-2025-mg5hc/v2",
  "fulltext_url": null,
  "id": "fm1z0zxk67msp",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-mg5hc/v2",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2208|Molecular Junctions and Nanostructures"
    ]
  ],
  "openalex": "W7221650565",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv-2025-mg5hc/v2",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/fm1z0zxk67msp.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:24Z",
      "native_id": "10.26434/chemrxiv-2025-mg5hc",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-mg5hc/v2"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "Molecular Engineering of Fano Resonances for Enhanced Single-Molecule Thermoelectrics",
  "title_text": "Molecular Engineering of Fano Resonances for Enhanced Single-Molecule Thermoelectrics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:24Z",
  "url": "https://research.draconitic.com/paper/fm1z0zxk67msp",
  "venue": "ChemRxiv",
  "versions": []
}