Benzimidazole-substituted bisanthracene: a highly efficient deep-blue triplet–triplet fusion OLED emitter at low dopant concentration

• Published in: Materials today chemistry Vol. 26; p. 101185
• Main Authors: Chen, C.-H., Hsiao, Z.-C., Fan, B.-A., Hou, L.-J., Lin, J.-H., Lin, B.-Y., Liu, K.-T., Huang, Y.-R., Zhang, Y.Z., Dzeng, Y.-C., Chiu, T.-L., Lee, J.-H., Tan, J., Chen, C., Leung, M.-k.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2022
• Subjects: Fluorescence; Organic light emitting diode (OLED); Time-resolved electroluminescence (TrEL); Triplet–triplet fusion (TTF); Time-resolved electroluminescence (TrEL); Fluorescence; Triplet–triplet fusion (TTF); Organic light emitting diode (OLED)
• ISSN: 2468-5194; 2468-5194
• DOI: 10.1016/j.mtchem.2022.101185

Two anthracene derivatives, MAnBz and DiAnBz, have been developed as emitters for deep-blue triplet–triplet fusion (TTF) fluorescence organic light emitting diodes (OLEDs). DiAnBz bearing two anthracene units at a closed distance, separated by one phenylene moiety, shows high photoluminescent quantum yields and deep-blue emission. The remarkable maximum external quantum efficiency (EQEmax) of 6.7% and 8.3% are obtained from DiAnBz-OLEDs with pristine prompt fluorescence and TTF fluorescence models, respectively. In particular, effectively diffusive TTF characteristics still can be detected at DiAnBz-OLED with an extreme low emitter concentration of 1 wt%, whose device performance exhibited a high EQEmax of 7.0% with deep blue emission at CIE (0.148, 0.078). The diffusive TTF characteristics with 20 times shorter delayed emission lifetime (τ2 of 3–4 μs), in comparison with that of MAnBz (τ2 of 60–70 μs) in the time-resolved electroluminescence experiments. This implies that pairing and TTF of the DiAnBz triplet excitons are more effective than that of MAnBz in the light emitting layer. [Display omitted] •Two new anthracene-based triplet–triplet fusion (TTF) emitters MAnBz and DiAnBz were developed.•MAnBz and DiAnBz possess a high photoluminescence quantum yield closed to 90%.•DiAnBz single-emitting layer organic light emitting diode showed the prompt fluorescent emission with maximum external quantum efficiency (EQEmax) of 6.7%.•DiAnBz TTF-organic light emitting diode achieved a high EQEmax of 8.3% with Commission International de L'Eclairge coordinates (0.145, 0.110).•DiAnBz also showed the effectively diffusive TTF mechanism at an extreme low dopant concentration case.