Carbazole/Triarylamine Based Polymers as a Hole Injection/Transport Layer in Organic Light Emitting Devices

2012 ◽  
Vol 12 (5) ◽  
pp. 4330-4334 ◽  
Author(s):  
Hui Wang ◽  
Jeong-Tak Ryu ◽  
Younghwan Kwon
Keyword(s):  
Transport Layer ◽  
Hole Injection ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Organic Light Emitting Devices

Hole Injection Enhancements of a CoPc and CoPc:NPB Mixed Layer in Organic Light-Emitting Devices

2012 ◽  
Vol 116 (24) ◽  
pp. 13210-13216 ◽  
Author(s):  
Hyunbok Lee ◽  
Jeihyun Lee ◽  
Kwangho Jeong ◽  
Yeonjin Yi ◽  
Jung Han Lee ◽  
...  
Keyword(s):  
Mixed Layer ◽  
Hole Injection ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Organic Light Emitting Devices

scholarly journals Sub–turn-on exciton quenching due to molecular orientation and polarization in organic light-emitting devices

2020 ◽  
Vol 6 (32) ◽  
pp. eabb2659
Author(s):  
John S. Bangsund ◽  
Jack R. Van Sambeek ◽  
Nolan M. Concannon ◽  
Russell J. Holmes
Keyword(s):  
Transport Layer ◽  
Electron Transport Layer ◽  
Intrinsic Polarization ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Turn On ◽  
Organic Light ◽  
Organic Light Emitting Devices ◽  
Lock In ◽  
Selection Of

The efficiency of organic light-emitting devices (OLEDs) is often limited by roll-off, where efficiency decreases with increasing bias. In most OLEDs, roll-off primarily occurs due to exciton quenching, which is commonly assumed to be active only above device turn-on. Below turn-on, exciton and charge carrier densities are often presumed to be too small to cause quenching. Using lock-in detection of photoluminescence, we find that this assumption is not generally valid; luminescence can be quenched by >20% at biases below turn-on. We show that this low-bias quenching is due to hole accumulation induced by intrinsic polarization of the electron transport layer (ETL). Further, we demonstrate that selection of nonpolar ETLs or heating during deposition minimizes these losses, leading to efficiency enhancements of >15%. These results reveal design rules to optimize efficiency, clarify how ultrastable glasses improve OLED performance, and demonstrate the importance of quantifying exciton quenching at low bias.

Sign in / Sign up

Export Citation Format

Share Document