Electronic structure and reactivity descriptors of BN-doped naphthalimide–carbazole bipolar OLED emitters: a DFT/TD-DFT study
Chemical Papers, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s11696-026-05463-4
- Dergi Adı: Chemical Papers
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Chemical Abstracts Core, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Bipolar emitters, BN-doping, DFT, OLED, TD-DFT
- Sivas Cumhuriyet Üniversitesi Adresli: Evet
Özet
Organic light-emitting diode (OLED) performance depends on controlling molecular electronic structure to achieve efficient charge transport and stable emission. Naphthalimide–carbazole bipolar emitters provide a donor–acceptor platform in which electronic properties can be tuned through structural modification. In this work, three reference compounds (1–3), containing carbazole and triphenylamine donor units linked to a naphthalimide acceptor, were investigated together with their boron–nitrogen (BN) isosteric analogues. DFT and TD-DFT calculations were performed to examine frontier orbital energies, global reactivity descriptors, molecular electrostatic potential distributions, thermodynamic stability, and excited-state properties. The parent compounds exhibit HOMO–LUMO gaps of 2.337 eV (1), 2.272 eV (2), and 2.938 eV (3), confirming stronger donor–acceptor interaction in compounds 1 and 2. The electronic response depends strongly on the substitution position. Incorporation along the π-bridge narrows the energy gap to 2.212 eV for 2-BN(p2), stabilizes the LUMO level, and promotes more effective charge transfer. Relative Gibbs free-energy calculations identify the p4 and p6 isomers as the most favorable structures, with ΔGrel values below 0.6 kcal mol−1 throughout the investigated series. TD-DFT calculations further predict a bathochromic shift from 302 to 352 nm together with an oscillator strength of 1.4158 for 1-BN(p4). Overall, the calculations identify π-bridge BN incorporation as the substitution pattern producing the strongest combined improvement in electronic communication, excited-state response, and thermodynamic stability, offering a molecular basis for the design of high-performance bipolar OLED emitters.