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Efficient and Bright Organic Radical Light-Emitting Diodes with Low Efficiency Roll-Off.
Cho, Hwan-Hee; Gorgon, Sebastian; Hung, Hsiao-Chun; Huang, Jun-Yu; Wu, Yuh-Renn; Li, Feng; Greenham, Neil C; Evans, Emrys W; Friend, Richard H.
Afiliación
  • Cho HH; Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
  • Gorgon S; Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
  • Hung HC; Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, 10617, Taipei, Taiwan.
  • Huang JY; Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, 10617, Taipei, Taiwan.
  • Wu YR; Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, 10617, Taipei, Taiwan.
  • Li F; State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Avenue 2699, Changchun, 130012, P. R. China.
  • Greenham NC; Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
  • Evans EW; Department of Chemistry, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
  • Friend RH; Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
Adv Mater ; 35(45): e2303666, 2023 Nov.
Article en En | MEDLINE | ID: mdl-37684741
Organic radicals have been of interest due to their potential to replace nonradical-based organic emitters, especially for deep-red/near-infrared (NIR) electroluminescence (EL), based on the spin-allowed doublet fluorescence. However, the performance of the radical-based EL devices is limited by low carrier mobility which causes a large efficiency roll-off at high current densities. Here, highly efficient and bright doublet EL devices are reported by combining a thermally activated delayed fluorescence (TADF) host that supports both electron and hole transport and a tris(2,4,6-trichlorophenyl)methyl-based radical emitter. Steady-state and transient photophysical studies reveal the optical signatures of doublet luminescence mechanisms arising from both host and guest photoexcitation. The host system presented here allows balanced hole and electron currents, and a high maximum external quantum efficiency (EQE) of 17.4% at 707 nm peak emission with substantially improved efficiency roll-off is reported: over 70% of the maximum EQE (12.2%) is recorded at 10 mA cm-2 , and even at 100 mA cm-2 , nearly 50% of the maximum EQE (8.4%) is maintained. This is an important step in the practical application of organic radicals to NIR light-emitting devices.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Adv Mater Asunto de la revista: BIOFISICA / QUIMICA Año: 2023 Tipo del documento: Article Pais de publicación: Alemania
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Adv Mater Asunto de la revista: BIOFISICA / QUIMICA Año: 2023 Tipo del documento: Article Pais de publicación: Alemania