{
  "abstract": "Curved nitrogen-doped polycyclic aromatic hydrocarbons offer a rigid and nonplanar framework for investigating how donor identity regulates the balance between locally excited and chargetransfer states in thermally activated delayed fluorescence (TADF) emitters. Here, a pyrido[2,3b]quinoxaline unit was integrated into a dibenzo[b,f]azepine-based polycyclic aromatic hydrocarbon scaffold and functionalized with one of 3,6-di-tert-butylcarbazole (TBCzPyN-PAH), diphenylamine (DPAPyN-PAH), 9,9-dimethyl-9,10-dihydroacridine (DMAcPyN-PAH), or phenoxazine (PXZPyN-PAH) donor moieties. The resulting series provides a common acceptor framework in which the electronic and conformational properties of the peripheral donor affect the 2 energies of the excited states. Donor substitution tunes the emission maximum in toluene from 528 to 697 nm. In 2 wt% doped films in CBP, these compounds emit from 519 to 622 nm with PLQY of up to 58%. Temperature-dependent time-resolved photoluminescence confirms TADF for all investigated compounds except for the DPA derivative. Across the TADF-active series, the singlet–triplet energy gap, ΔEST, decreases from 0.22 to 0.03 eV and the delayed fluorescence lifetime shortens from 8.5 ms to 29 μs. Vacuum-deposited OLEDs with TBCzPyN-PAH showed EQEmax, of 21.6% at an electroluminescence maximum of 538 nm, whereas the device with PXZPyN-PAH emitted at 606 nm and showed a lower EQEmax of 7.2% but with a milder efficiency roll-off.",
  "abstract_shown": true,
  "affiliations": [
    "Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw, Poland, 01-224",
    "Organic Semiconductor Centre, EaStCHEM School of Chemistry",
    "University of St Andrews",
    "School of Physics & Astronomy"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Jakub Wagner"
    },
    {
      "affs": [
        1,
        2,
        3
      ],
      "name": "Eglė Tankelevičiūtė"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Haoyang Li"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Tomas Matulaitis"
    },
    {
      "affs": [
        0
      ],
      "name": "Maja Morawiak"
    },
    {
      "affs": [
        0
      ],
      "name": "Maciej Jelecki"
    },
    {
      "affs": [
        3,
        2
      ],
      "name": "Ifor D. W. Samuel"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Eli Zysman-Colman",
      "orcid": "0000-0001-7183-6022"
    },
    {
      "affs": [
        0
      ],
      "name": "Marcin Lindner",
      "orcid": "0000-0002-5514-674X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f4g53h8ffg9cn.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008900/v1",
  "fulltext_url": null,
  "id": "f4g53h8ffg9cn",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008900/v1",
  "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|Organic Light-Emitting Diodes Research"
    ]
  ],
  "openalex": "W7213365058",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008900/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-16",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/f4g53h8ffg9cn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008900",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008900/v2"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "Red TADF Pyridoquinoxaline-Annulated Curved Nitrogen-Doped PAHs and their use in OLEDs",
  "title_text": "Red TADF Pyridoquinoxaline-Annulated Curved Nitrogen-Doped PAHs and their use in OLEDs",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:19Z",
  "url": "https://research.draconitic.com/paper/f4g53h8ffg9cn",
  "venue": "ChemRxiv",
  "versions": []
}