Intense deep blue exciplex electroluminescence from NPB/TPBi:PPh3O-based OLEDs and their intrinsic degradation mechanisms (Conference Presentation)

2016 ◽  
Author(s):  
Joseph Shinar ◽  
Chamika Hippola ◽  
Dusan Danilovic ◽  
Ujjal Bhattacharjee ◽  
Jacob W. Petrich ◽  
...  
Keyword(s):  
Degradation Mechanisms ◽  
Deep Blue ◽  
Intrinsic Degradation

Luminance degradation and recovery studies in Alq3 based Organic light emitting diodes

2011 ◽  
Vol 1360 ◽  
Author(s):  
K. Sudheendra Rao ◽  
Girija S. Samal ◽  
Y. N. Mohapatra
Keyword(s):  
Light Emitting Diodes ◽  
Time Windows ◽  
Organic Light Emitting Diodes ◽  
Degradation Mechanisms ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Stress Cycles ◽  
Intrinsic Degradation ◽  
Distinguishing Features

AbstractThough organic light emitting diodes are being commercialized in many applications, issues relating to lifetime and degradation remain as fundamental concerns limiting performance. A coherent understanding of degradation mechanisms is yet to emerge. We focus on intrinsic degradation of high quality Alq3 based diodes due to electrical stressing. We monitor progressive luminance degradation and recovery by introducing well defined relaxation time windows in the current stress cycles. The method helps to clearly distinguish between recoverable and permanent degradation systematically. The voltage shift due to degradation and recovery is also monitored as a function of time. Further, we introduce a method of reconstructing the transients of the recoverable part using progressive isolated current pulses as a probe. The recovery of degradation is related to the charging and discharging of the traps in the device and our method provides a technique of measuring significant parameters of trapping through luminance transients. The origin and distinguishing features of the two types of degradation are discussed.

The Devil and the Deep Blue Lake: How Natural Area Acquisition and Stewardship Helps Protect the Major Drinking Reservoir in Northwestern Arkansas

2019 ◽  
Vol 39 (1) ◽  
pp. 78 ◽  
Author(s):  
Dustin T. Lynch ◽  
C. Theo Witsell ◽  
Bryan A. Rupar ◽  
William C. Holimon ◽  
Darrell W. Bowman
Keyword(s):  
Natural Area ◽  
Deep Blue ◽  
Blue Lake ◽  
The Devil

Controlled Injection of Holes into ALQ3 Based Oleds by Means of An Oxidized Transport Layer

2001 ◽  
Vol 708 ◽  
Author(s):  
Mathew K. Mathai ◽  
Keith A. Higginson ◽  
Bing R. Hsieh ◽  
Fotios Papadimitrakopoulos
Keyword(s):  
Indium Tin Oxide ◽  
Oxidative Degradation ◽  
Transport Layer ◽  
Hole Injection ◽  
Carrier Injection ◽  
Salt Loading ◽  
Light Emitting ◽  
Hole Transporting ◽  
Intrinsic Degradation ◽  
Variable Conductivity

ABSTRACTIn this paper we report a method for tuning the extent of hole injection into the active light emitting tris- (8-hydroxyquinoline) aluminum (Alq3) layer in organic light emitting diodes (OLEDs). This is made possible by modifying the indium tin oxide (ITO) anode with an oxidized transport layer (OTL) comprising a hole transporting polycarbonate of N,N'-bis(3-hydroxymethyl)-N,N'-bis(phenyl) benzidine and diethylene glycol (PC-TPB-DEG) doped with varying concentrations of antimonium hexafluoride salt of N,N,N',N'-tetra-p-tolyl-4,4'-biphenyldiamine (TMTPD+ SbF6-). The conductivity of the OTL can be changed over three orders of magnitude depending on salt loading. The analysis of hole and electron current variations in these devices indicates that optimizing the conductivity of the OTL enables the modulation of hole injection into the Alq3 layer. The bipolar charge transport properties for OLEDs in which the interfacial carrier injection barriers have been minimized, are governed by the conductivities of the respective layers and in this case it is shown that the variable conductivity of the OTL does allow for better control of the same. Accordingly, varying the concentration of holes in the device indicates that beyond an optimum concentration of holes, further hole injection results in the formation of light quenching cationic species and the initiation of oxidative degradation processes in the Alq3 layer, thus accelerating the intrinsic degradation of these devices. The variable conductivity of the OTL can hence be used to minimize the occurrence of these processes.

Tetraphenylbenzene-based AIEgens: the Horizontally Oriented Emitters for highly Efficient Non-doped Deep Blue OLEDs and Host for High-Performance Hybrid WOLEDs

2020 ◽  
Author(s):  
Pengbo Han ◽  
Zeng Xu ◽  
Chengwei Lin ◽  
Dongge Ma ◽  
Anjun Qin ◽  
...  
Keyword(s):  
High Performance ◽  
General Strategy ◽  
Flat Panel Displays ◽  
Light Emitting ◽  
Horizontal Orientation ◽  
Deep Blue ◽  
Full Color ◽  
High Emission ◽  
White Oleds ◽  
Low Efficiency

Deep blue organic-emitting fluorophores are crucial for application in white lighting and full color flat-panel displays but emitters with high color quality and efficiency are rare. Herein, novel deep blue AIE luminogens (AIEgens) with various donor units and an acceptor of cyano substituted tetraphenylbenzene (TPB) cores were developed and used to fabricate non-doped deep blue and hybrid white organic light-emitting diodes (OLEDs). Benefiting from its high emission efficiency and high proportion of horizontally oriented dipoles in the film state, the non-doped deep blue device based on CN-TPB-TPA realized a maximum external quantum efficiency 7.27%, with a low efficiency roll-off and CIE coordinates of (0.15, 0.08). Moreover, efficient two-color hybrid warm white OLEDs (CIE<sub>x,y</sub> = 0.43, 0.45) were achieved using CN-TPB-TPA as the blue-emitting layer and phosphor doped host, which realized maximum current, power, external quantum efficiencies 58.0 cd A<sup>-1</sup>, 60.7 lm W<sup>-1</sup> and 19.1%, respectively. This work provides a general strategy to achieve high performance, stable deep blue and hybrid white OLEDs by construction of AIEgens with excellent horizontal orientation

Lithium-ion Battery Degradation Mechanisms and Failure Analysis Methodology

2012 ◽  
Author(s):  
Bhanu Sood ◽  
Lucas Severn ◽  
Michael Osterman ◽  
Michael Pecht ◽  
Anton Bougaev ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Lithium Ion Batteries ◽  
Elevated Temperatures ◽  
Failure Process ◽  
Lithium Ion ◽  
Degradation Mechanisms ◽  
Analysis Methodology ◽  
Depth Of Discharge ◽  
Battery Degradation ◽  
Non Destructive

Abstract A review of the prevalent degradation mechanisms in Lithium ion batteries is presented. Degradation and eventual failure in lithium-ion batteries can occur for a variety of dfferent reasons. Degradation in storage occurs primarily due to the self-discharge mechanisms, and is accelerated during storage at elevated temperatures. The degradation and failure during use conditions is generally accelerated due to the transient power requirements, the high frequency of charge/discharge cycles and differences between the state-of-charge and the depth of discharge influence the degradation and failure process. A step-by-step methodology for conducting a failure analysis of Lithion batteries is presented. The failure analysis methodology is illustrated using a decision-tree approach, which enables the user to evaluate and select the most appropriate techniques based on the observed battery characteristics. The techniques start with non-destructive and non-intrusive steps and shift to those that are more destructive and analytical in nature as information about the battery state is gained through a set of measurements and experimental techniques.

Highly Efficient Deep Blue Fluorescence Emitter Based on Highly Conjugated Boron Structure

2019 ◽  
pp. 822
Author(s):  
Hanjong Yoo ◽  
Daehyun Ahn ◽  
Hyuna Lee ◽  
Juyoung Lee ◽  
Janghyuk Kwon
Keyword(s):  
Blue Fluorescence ◽  
Highly Efficient ◽  
Deep Blue
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