Optical detection of charge carriers in organic light‐emitting diodes

1996 ◽  
Vol 69 (1) ◽  
pp. 70-72 ◽  
Author(s):  
M. Redecker ◽  
H. Bässler
Keyword(s):  
Light Emitting Diodes ◽  
Optical Detection ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

scholarly journals Highly Efficient Single-Layer Phosphorescent Organic Light-Emitting Diodes Based on Co-Host Structure

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2029
Author(s):  
Tianyu Zhang ◽  
Asu Li ◽  
Ren Sheng ◽  
Mingyang Sun ◽  
Ping Chen
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Single Layer ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Superior Performance ◽  
Light Emitting ◽  
Organic Light ◽  
Exciton Recombination ◽  
Host Structure

High-efficiency single-layer organic light-emitting diodes (OLEDs) based on a simple structure doped with iridium(III) bis(4-phenylthieno[3,2-c]pyridinato-N,C2′) acetylacetonate (PO-01) as emission dyes are realized, achieving maximum current efficiency (CE) and power efficiency (PE) of 37.1 cd A−1 and 33.3 lm W−1 as well as low turn-on voltage of 3.31 V. Such superior performance is mainly attributed to the employment of a uniform co-host structure and assisted charge transport property of phosphors dyes, which were in favor of the balance of charge carrier injection and transport in the single emitting layer (EML). Moreover, systematic researches on the position of exciton recombination region and the dopant effect on charge carriers were subsequently performed to better understand the operational mechanism. It could be experimentally found that the orange emitting dopants promoted the acceleration of the charge carriers transport and raised the exciton recombination efficiency, eventually leading to an excellent performance of single-layer OLEDs.

23.1: Invited Paper: Luminescence Quenching by Charge Carriers in Organic Light-Emitting Diodes

2009 ◽  
Vol 40 (1) ◽  
pp. 306 ◽  
Author(s):  
Millard Wyman ◽  
Alfred Marchetti ◽  
Lewis Rothberg ◽  
Ralph Young ◽  
Denis Kondakov
Keyword(s):  
Light Emitting Diodes ◽  
Luminescence Quenching ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

Organic Light - Emitting Diodes and their Applications

2014 ◽  
Vol 357 ◽  
pp. 29-93 ◽  
Author(s):  
V.K. Chandra ◽  
B.P. Chandra ◽  
Piyush Jha
Keyword(s):  
Quantum Efficiency ◽  
Organic Material ◽  
Organic Molecules ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Triplet Excitons

Organic light emitting diodes (OLEDs) have been the focus of intense study since the late 1980s, when the low voltage organic electroluminescence in small organic molecules such as Alq3, and large organic molecules such as polymers (PPV), was reported. Since that time, research has continued to demonstrate the potential of OLEDs as viable systems for displays and eco-friendly lighting applications. OLEDs offer full colour display, reduced manufacturing cost, larger viewing angle, more flexible, lower power consumption, better contrast, slimmer, etc. which help in replacing the other technologies such as LCD. The operation of OLEDs involves injection of charge carriers into organic semiconducting layers, recombination of charge carriers, formation of singlet and triplet excitons, and emission of light during decay of excitons. The maximum internal quantum efficiency of fluorescent OLEDs consisting of the emissive layer of fluorescent organic material is 25% because in this case only the 25% singlet excitons can emit light. The maximum internal quantum efficiency of phosphorescent OLEDs consisting of the emissive layer of fluorescent organic material mixed with phosphorescent material of heavy metal complexes such as platinum complexes, iridium complexes, etc. is nearly 100% because in this case both the 25% singlet excitons and 75% triplet excitons emit light. Recently, a new class of OLEDs based on thermally activated delayed fluorescence (TADF) has been reported, in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up-conversion from non-radiative triplet states to radiative singlet states while maintaining high radiative decay rates of more than 106decays per second. These molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels and provides an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency of more than 19 per cent, which is comparable to that achieved in high-efficiency phosphorescence-based OLEDs.The OLED technology can be used to make screens large enough for laptop, cell phones, desktop computers, televisions, etc. OLED materials could someday be applied to plastic and other materials to create wall-size video panels, roll-up screens for laptops, automotive displays, and even head wearable displays. Presently, the OLEDs are opening up completely new design possibilities for lighting in the world of tomorrow whereby the offices and living rooms could be illuminated by lighting panels on the ceiling. The present paper describes the salient features of OLEDs and discusses the applications of OLEDs in displays and solid state lighting devices. Finally, the challenges in the field of OLEDs are explored. Contents of Paper

scholarly journals Storage of charge carriers on emitter molecules in organic light-emitting diodes

2012 ◽  
Vol 86 (7) ◽  
Author(s):  
Caroline Weichsel ◽  
Lorenzo Burtone ◽  
Sebastian Reineke ◽  
Susanne I. Hintschich ◽  
Malte C. Gather ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light
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