Details

Autor(en) / Beteiligte

• Chen, Zhi‐Peng
• Wang, De‐Qi
• Zhang, Ming
• Wang, Kai
• Shi, Yi‐Zhong
• Chen, Jia‐Xiong
• Tao, Wen‐Wen
• Zheng, Cai‐Jun
• Tao, Si‐Lu
• Zhang, Xiao‐Hong

Titel

Optimization on Molecular Restriction for Highly Efficient Thermally Activated Delayed Fluorescence Emitters

Ist Teil von

• Advanced optical materials, 2018-12, Vol.6 (24), p.n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2018

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• To develop efficient thermally activated delayed fluorescence (TADF) emitters with optimal molecular restrictions for organic light‐emitting diodes (OLEDs), four novel TADF emitters are designed and synthesized: 5′‐(9,9‐dimethylacridin‐10(9H)‐yl)‐[1,1′:3′,1″‐terphenyl]‐2′,4,4″‐tricarbonitrile (oAcTBC), 5′‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)‐[1,1′:3′,1″‐terphenyl]‐2′,4,4″‐tricarbonitrile (oSpTBC), 2′‐(9,9‐dimethylacridin‐10(9H)‐yl)‐[1,1′:3′,1″‐terphenyl]‐4,4″,5′‐tricarbonitrile (mAcTBC), and 2′‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)‐[1,1′:3′,1″‐terphenyl]‐4,4″,5′‐tricarbonitrile (mSpTBC). The four compounds have similar constituent segments but different molecular restrictions by enhancing either segment rigidity or steric hindrance. The OLEDs using oAcTBC, oSpTBC, mAcTBC, and mSpTBC as the emitter exhibit maximum external quantum efficiencies of 20.9%, 26.8%, 19.2%, and 18.9%, respectively, consistent with their photoluminescence quantum yield values of 83.88%, 93.24%, 76.64%, and 65.02%. The best performance is successfully realized by oSpTBC with the optimal molecular restriction. This work suggests that appropriately enhancing the molecular restrictions with more rigid constituent segments is an optimal approach to improve the efficiencies of TADF emitters. Four thermally activated delayed fluorescence (TADF) emitters with similar constituent segments but different molecular restrictions are developed. The 5′‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)‐[1,1′:3′,1″‐terphenyl]‐2′,4,4″‐tricarbonitrile (oSpTBC)‐based organic light‐emitting diodes (OLEDs) exhibit highest efficiencies with a maximum external quantum efficiency (EQE) of 26.8%. These results suggest that appropriately enhancing the molecular restrictions with more rigid constituent segments is an optimal approach to improve the efficiencies of TADF emitters.