Patterning Scheme Based on Photoacid Induced Spectral Changes for Single Layer, Patterned Full Color Light Emitting Diodes

2006 ◽  
Vol 965 ◽  
Author(s):  
Maria Vasilopoulou ◽  
Giorgos Pistolis ◽  
Athanasios Botsialas ◽  
Nikos Stathopoulos ◽  
Maria Rangoussi ◽  
...  
Keyword(s):  
Single Layer ◽  
Spectral Shift ◽  
Blue Color ◽  
Light Emitting ◽  
Photoacid Generators ◽  
Onium Salts ◽  
Hole Transporting ◽  
Polymeric Layer ◽  
Different Color ◽  
Definition Of

ABSTRACTPhotochemically induced emission tuning (PIET) for the definition of different color emitting areas in a single conducting polymeric layer is demonstrated. The commercially available poly(9-vinylcarbazole) (PVK), well known as a hole transporting layer in OLEDs technology, was used. The three primary colors emitting areas in a single layer of PVK film were defined using a suitable green emitter 1-[4-(dimethylamino)phenyl]-6-phenylhexa-1,3,5,-triene (DMA-DPH) along with the red emitter (4-dimethylamino-4'-nitrostilbene) (DANS). The selected emitters were dispersed in the PVK films in the presence of a photoacid generator (PAG). Various onium salts were tested as photoacid generators in order to select those, which could cause effectivily the photoinduced protonation and emission tuning of the probes molecules. Through proton induced bleaching of the red emitter and proton induced spectral shift of the green one, the definition of all three primary color emitting areas was possible. In this way the unexposed areas of the film remain red, the areas exposed with the intermediate dose become green and the fully exposed areas emit blue color. Intermediate colors and white light can also be obtained.

Effect of Double Hole-Transporting Structure on Color Purity of Blue Organic Light-Emitting Diodes (BOLED)

2013 ◽  
Vol 311 ◽  
pp. 424-429
Author(s):  
Kan Lin Chen ◽  
Chien Jung Huang ◽  
Zong Jin Wu ◽  
Chih Chieh Kang ◽  
Wen Ray Chen ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Blue Color ◽  
Color Purity ◽  
Television System ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Hole Transporting ◽  
The Right

A blue organic light-emitting diode (OLED) with a double hole-transporting (DHT) structure has been developed. The blue color purity was improved by modulation the thickness of CBP layer. When the thicknesses of left CBP and right CBP are respectively 8 nm and 2 nm, the more pure blue coordinates are (0.155, 0.079), which are very close to the blue coordinates of the national television system committee (NTSC) standard (0.14, 0.08). Furthermore the current density, brightness and the luminous efficiency of device with the left CBP of 8 nm and the right CBP of 2 nm are respectively 144.7 mA/cm2, 1065 cd/m2 and 0.93 cd/A.

Highly efficient single-layer blue polymer light-emitting diodes based on hole-transporting group substituted poly(fluorene-co-dibenzothiophene-S,S-dioxide)

2017 ◽  
Vol 5 (37) ◽  
pp. 9680-9686 ◽  
Author(s):  
Feng Peng ◽  
Na Li ◽  
Lei Ying ◽  
Wenkai Zhong ◽  
Ting Guo ◽  
...  
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Single Layer ◽  
Random Copolymer ◽  
Hole Transport ◽  
Light Emitting ◽  
Hole Transporting ◽  
Polymer Light Emitting Diodes ◽  
Copolymer Poly

We developed a series of high-performance blue light-emitting polymers that contain hole-transport moieties comprising carbazole or triphenylamine substituents in the side chains of random copolymer poly(fluorene-co-dibenzothiophene-S,S-dioxide) (PFSO).

Covalent Functionalized Conjugated Dendrimers for Organic Light Emitting Diodes: Synthesis, Characterization, and the Deep Blue Electroluminescence

2011 ◽  
Vol 64 (2) ◽  
pp. 160 ◽  
Author(s):  
Yan Zhou ◽  
Lin Ding ◽  
Li-Ming Xiang ◽  
Jian Pei
Keyword(s):  
Light Emitting Diode ◽  
Photophysical Properties ◽  
Single Layer ◽  
Blue Colour ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Deep Blue ◽  
Organic Light ◽  
Hole Transporting ◽  
Cie Chromaticity

Two deep blue-emitting dendrimers 11 and 12 with carbazole containing dendrons were developed in this contribution. The carbazole-containing units were introduced to tune the charge-transporting property of the desired dendrimers. The investigation of photophysical properties, electrochemical, and electroluminescence properties demonstrated that the balance between electron and hole transporting was achieved from both dendrimers. The preliminary organic light-emitting diode (OLED) fabrication achieved a pure blue colour with stable CIE chromaticity coordinates (X: 0.15–0.16, Y: 0.09–0.10) for 11 and 12. Single layer deep blue emitting diode devices with higher efficiency are achieved without the colour changing. The investigation of OLED performance indicates that dendrimers 11 and 12 are promising light-emitting materials with pure blue colour and good colour stability for OLEDs.

Light-Emitting Diodes with Voltage-Switchable Colors from Semiconducting Polymer/Polymer Heterojunctions

1997 ◽  
Vol 488 ◽  
Author(s):  
Xuejun Zhang ◽  
Samson A. Jenekhe
Keyword(s):  
Light Emitting Diodes ◽  
Single Layer ◽  
Phenylene Vinylene ◽  
Light Sources ◽  
Semiconducting Polymer ◽  
Electroluminescent Devices ◽  
Light Emitting ◽  
Color Changes ◽  
Hole Transporting ◽  
Rigid Rod

AbstractReversible electroluminescence color changes with applied voltage have been observed in light-emitting diodes fabricated from semiconducting polymer heterojunctions consisting of an electron transporting polybenzobisthiazole and hole transporting poly(p-phenylene vinylene) when layer thicknesses are less than 60–100 nm. Enhanced device performances such as lower turn-on voltage and higher efficiency and luminance were also obtained compared to single-layer devices. The observed voltage-switchable emission colors in these nanoscale heterojunction light sources can be understood in terms of spatial confinement effects which are related to field-dependent charge transport and trapping processes in the materials. These results also demonstrate the use of new high temperature rigid-rod polymers as electron transport and emissive layers in electroluminescent devices.

Synthesis and Structure - Property Relationships of Symmetric Ambipolar Quaterfluorene-Containing Oxadiazole as a Central Core and Diphenylamine as End-capping Moieties

2008 ◽  
Vol 61 (7) ◽  
pp. 541 ◽  
Author(s):  
Fan Yang ◽  
Xiao Ling Zhang ◽  
Mo Jun Xiong ◽  
Zi Jian Cao ◽  
Ping Fang Xia ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Layer ◽  
Cross Coupling ◽  
Structure Property ◽  
Electrochemical Stabilities ◽  
Light Emitting ◽  
Structure Property Relationships ◽  
Hole Transporting ◽  
End Capping ◽  
Double Charge

A facile approach for the synthesis of the symmetric ambipolar quaterfluorene, OF(4)OX-NPh, with hole-transporting and electron-transporting moieties by Suzuki cross-coupling as a key reaction has been developed. This novel ambipolar quaterfluorene exhibits high thermal and electrochemical stabilities and is expected to possess potential application as a double charge-transfer and light-emitting material in the field of single-layer organic emitting diodes.

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.

Sign in / Sign up

Export Citation Format

Share Document