Thermally Activated Delayed Fluorescent Dendrimers that Underpin High-Efficiency Host-Free Solution-Processed Organic Light-Emitting Diodes

Title data

Sun, Dianming ; Duda, Eimantas ; Fan, Xiaochun ; Saxena, Rishabh ; Zhang, Ming ; Bagnich, Sergey ; Zhang, Xiaohong ; Köhler, Anna ; Zysman-Colman, Eli:
Thermally Activated Delayed Fluorescent Dendrimers that Underpin High-Efficiency Host-Free Solution-Processed Organic Light-Emitting Diodes.
In: Advanced Materials. Vol. 34 (2022) Issue 23 . - No. 2110344.
ISSN 1521-4095
DOI: https://doi.org/10.1002/adma.202110344

Official URL:

Abstract in another language

Abstract The development of high-performance solution-processed organic light-emitting diodes (OLEDs) remains a challenge. An effective solution, highlighted in this work, is to use highly efficient thermally activated delayed fluorescence (TADF) dendrimers as emitters. Here, the design, synthesis, density functional theory (DFT) modeling, and photophysics of three triazine-based dendrimers, tBuCz2pTRZ, tBuCz2mTRZ, and tBuCz2m2pTRZ, is reported, which resolve the conflicting requirements of achieving simultaneously a small ΔEST and a large oscillator strength by incorporating both meta- and para-connected donor dendrons about a central triazine acceptor. The solution-processed OLED containing a host-free emitting layer exhibits an excellent maximum external quantum efficiency (EQEmax) of 28.7%, a current efficiency of 98.8 cd A−1, and a power efficiency of 91.3 lm W−1. The device emits with an electroluminescence maximum, λEL, of 540 nm and Commission International de l'Éclairage (CIE) color coordinates of (0.37, 0.57). This represents the most efficient host-free solution-processed OLED reported to date. Further optimization directed at improving the charge balance within the device results in an emissive layer containing 30 wt% OXD-7, which leads to an OLED with the similar EQEmax of 28.4% but showing a significantly improved efficiency rolloff where the EQE remains high at 22.7% at a luminance of 500 cd m−2.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Keywords:	carbazole; external quantum efficiency; host-free organic light-emitting diodes; solution-processing; thermally activated delayed fluorescence dendrimers
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter > Chair Experimental Physics II - Optoelectronics of Soft Matter - Univ.-Prof. Dr. Anna Köhler Faculties Faculties > Faculty of Mathematics, Physics und Computer Science
Result of work at the UBT:	Yes
DDC Subjects:	500 Science > 530 Physics
Date Deposited:	10 May 2022 08:10
Last Modified:	21 Oct 2022 10:51
URI:	https://eref.uni-bayreuth.de/id/eprint/69563