Role of Linker Functionality in Polymers Exhibiting Main‐Chain Thermally Activated Delayed Fluorescence

Advanced Science

Peter K. H. Ho¹  Lay‐Lay Chua¹  Rui‐Qi Png¹  Bas van derZee²  Charusheela Ramanan²  Jasper J. Michels²  Kai Philipps²  Paul W. M. Blom²  Gert‐Jan A. H. Wetzelaer²  Esther del Pino Rosendo²  Yutaka Ie³ 

[1] Department of Physics National University of Singapore Lower Kent Ridge Road Singapore S117550 Singapore;Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany;The Institute of Scientific and Industrial Research (ISIR) Osaka University 8‐1 Mihogaoka Ibaraki Osaka 567‐0047 Japan;

关键词: high efficiency;    organic light‐emitting diodes;    thermally activated delayed fluorescence;   

DOI  :  10.1002/advs.202200056

来源: DOAJ

【 摘 要 】

Abstract Excellent performance has been reported for organic light‐emitting diodes (OLEDs) based on small molecule emitters that exhibit thermally activated delayed fluorescence. However, the necessary vacuum processing makes the fabrication of large‐area devices based on these emitters cumbersome and expensive. Here, the authors present high performance OLEDs, based on novel, TADF polymers that can be readily processed from a solution. These polymers are based on the acridine‐benzophenone donor–acceptor motif as main‐chain TADF chromophores, linked by various conjugated and non‐conjugated spacer moieties. The authors’ extensive spectroscopic and electronic analysis shows that in particular in case of alkyl spacers, the properties and performance of the monomeric TADF chromophores are virtually left unaffected by the polymerization. They present efficient solution‐processed OLEDs based on these TADF polymers, diluted in oligostyrene as a host. The devices based on the alkyl spacer‐based TADF polymers exhibit external quantum efficiencies (EQEs) ≈12%, without any outcoupling‐enhancing measures. What's more, the EQE of these devices does not drop substantially upon diluting the polymer down to only ten weight percent of active material. In contrast, the EQE of devices based on the monomeric chromophore show significant losses upon dilution due to loss of charge percolation.

【 授权许可】

Unknown