{
  "abstract": "Organic laser dyes emitting at long wavelengths often suffer from high amplified spontaneous emission (ASE) and lasing thresholds because nonradiative relaxation is promoted by the energy-gap law. Herein, a deep-red-emitting laser dye, trans - BTDA , is developed using a donor–acceptor–π–acceptor–donor framework combining triphenylamine donors and a vinylene-bridged benzothiadiazole (BTD) dimer as the acceptor–π–acceptor core. The π-extended BTD dimer narrows the energy gap, while mixed locally excited and charge-transfer character with favorable orbital overlap contributes to a large radiative rate constant ( k r ). In thin films, trans - BTDA exhibits deep-red ASE at 652 nm with a low threshold of 3.54 μJ cm –2 , while trans - SBA , containing a stilbene unit instead of the BTD dimer, exhibits blue ASE at 476 nm with a threshold of 0.81 μJ cm –2 . Both dyes also achieve low-threshold distributed feedback lasing at 651 and 473 nm, with thresholds of 0.85 μJ cm –2 and 0.33 μJ cm –2 , respectively. Minimal spectral overlap between the ASE and ground- and excited-state absorption spectra indicates low optical losses. trans - BTDA further shows favorable photostability under continuous excitation, even for the red emitter. In conclusion, the vinylene-bridged BTD dimer enables sharp deep-red emission with a large k r and low ASE and lasing thresholds.",
  "abstract_shown": true,
  "affiliations": [
    "Division of Materials Science",
    "Nara Institute of Science and Technology (NAIST",
    "International Institute for Carbon Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan, 819-0395",
    "Organic Photonics and Electronics International Laboratory (OPHELIA, CNRS-Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan, 819-0395",
    "Center for Organic Photonics and Electronics Research (OPERA, Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan, 819-0395",
    "Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems (CMS",
    "Kyushu University",
    "Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan, 819-0395",
    "College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, Japan, 525-8577",
    "Quantum and Spacetime Research Institute (QSRI, Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan, 819-0395",
    "Medilux Research Center"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Ryoko Oyama",
      "orcid": "0000-0001-9289-0837"
    },
    {
      "affs": [
        2,
        3,
        4,
        5,
        6,
        7
      ],
      "name": "Youhei Chitose",
      "orcid": "0000-0003-4746-784X"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Yusei Ishii"
    },
    {
      "affs": [
        4
      ],
      "name": "Takuma Saeki"
    },
    {
      "affs": [
        8
      ],
      "name": "Yuki Nagai",
      "orcid": "0000-0002-4629-4863"
    },
    {
      "affs": [
        8
      ],
      "name": "Yoichi Kobayashi",
      "orcid": "0000-0003-3339-3755"
    },
    {
      "affs": [
        2,
        3,
        4,
        9
      ],
      "name": "Chihaya Adachi",
      "orcid": "0000-0001-6117-9604"
    },
    {
      "affs": [
        0,
        1,
        10
      ],
      "name": "Naoki Aratani",
      "orcid": "0000-0002-3181-6526"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ardwcf2nk4wc0.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008814/v1",
  "fulltext_url": null,
  "id": "ardwcf2nk4wc0",
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  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008814/v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Luminescence and Fluorescent Materials"
    ]
  ],
  "openalex": "W7213242347",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008814/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-14",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/ardwcf2nk4wc0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008814",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008814/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Luminescence and Fluorescent Materials",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Low-threshold Deep-red Organic Laser Dye Based on a Vinylene-bridged Benzothiadiazole Dimer in a Donor–Acceptor–π–Acceptor–Donor Framework",
  "title_text": "Low-threshold Deep-red Organic Laser Dye Based on a Vinylene-bridged Benzothiadiazole Dimer in a Donor–Acceptor–π–Acceptor–Donor Framework",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:19Z",
  "url": "https://research.draconitic.com/paper/ardwcf2nk4wc0",
  "venue": "ChemRxiv",
  "versions": []
}