Donor and Acceptor Fused 16,16‐Dimethyl‐11,16‐dihydrodibenzo[2,3:5,6]pyrrolizino[1,7‐ ab ]acridine as a Blue‐Emitting Chromophore for High External Quantum Efficiency and Long Lifetime

2020 ◽  
Vol 8 (17) ◽  
pp. 2000480
Author(s):  
Vilas Venunath Patil ◽  
Kyung Hyung Lee ◽  
Jun Yeob Lee
2019 ◽  
Vol 7 (10) ◽  
pp. 2919-2926 ◽  
Author(s):  
Ji Gwang Yu ◽  
Si Hyun Han ◽  
Ha Lim Lee ◽  
Wan Pyo Hong ◽  
Jun Yeob Lee

A novel molecular design employing a backbone structure freezing linker was developed to improve the external quantum efficiency, lifetime and emission profile of thermally activated delayed fluorescence (TADF) emitters.


2020 ◽  
Vol 14 (1) ◽  
pp. 011004
Author(s):  
Shubhra S. Pasayat ◽  
Chirag Gupta ◽  
Matthew S. Wong ◽  
Ryan Ley ◽  
Michael J. Gordon ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuwei Guo ◽  
Sofia Apergi ◽  
Nan Li ◽  
Mengyu Chen ◽  
Chunyang Yin ◽  
...  

AbstractPerovskite light emitting diodes suffer from poor operational stability, exhibiting a rapid decay of external quantum efficiency within minutes to hours after turn-on. To address this issue, we explore surface treatment of perovskite films with phenylalkylammonium iodide molecules of varying alkyl chain lengths. Combining experimental characterization and theoretical modelling, we show that these molecules stabilize the perovskite through suppression of iodide ion migration. The stabilization effect is enhanced with increasing chain length due to the stronger binding of the molecules with the perovskite surface, as well as the increased steric hindrance to reconfiguration for accommodating ion migration. The passivation also reduces the surface defects, resulting in a high radiance and delayed roll-off of external quantum efficiency. Using the optimized passivation molecule, phenylpropylammonium iodide, we achieve devices with an efficiency of 17.5%, a radiance of 1282.8 W sr−1 m−2 and a record T50 half-lifetime of 130 h under 100 mA cm−2.


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