Fabrication and Characterization of OLED with Magnesium Complex of Benzimidazol-2-Yl Pyridine as Emission Layer

2012 ◽  
Vol 557-559 ◽  
pp. 748-754
Author(s):  
Yu Feng Lin ◽  
Pin Wen Cheng ◽  
Shih Hsuan Chiu ◽  
Chen Hao Wang ◽  
Shung Jim Yang ◽  
...  
Keyword(s):  
Light Emission ◽  
Visible Region ◽  
Blue Emission ◽  
Decomposition Temperature ◽  
Melting Transition ◽  
Emission Layer ◽  
Maximum Brightness ◽  
Light Emitting ◽  
Light Emitting Devices

A bright blue emission material, bis {(benzimidazol-2-yl) Pyridenato} magnesium (MgBIP) used for organic light emitting devices, has been synthesized. The decomposition temperature was observed at 517 °C and no melting transition (Tm) of MgBIP was observed up to 400 °C. For three-layer LED devices with the configuration of ITO/NPB/MgBIP/ Alq3/MgAg, the white light emission covering the whole visible region from 400 to 750 nm with the maximum brightness of 2770 cd/m2and current density of 304 mA/cm2was observed.

Preparation and Characterization of Organic Light Emitting Devices Using QD Dopant

2004 ◽  
Vol 449-452 ◽  
pp. 1021-1024 ◽  
Author(s):  
Jung Yohn Cho ◽  
Ho Jung Chang
Keyword(s):  
Luminous Efficiency ◽  
Host Material ◽  
Oled Device ◽  
Emission Layer ◽  
Maximum Brightness ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Organic Light Emitting Devices

Two types of the organic light-emitting devices (OLEDs) with different emission structures were prepared using Alq3 (aluminum tris 8-hydroxyquinoline) host material and quinacridone (QD) dopant at the emission layer. One is the OLED device with emission layer consisting of Alq3 host material doped with QD dopant ("codoped OLED"). The another one has a seperated QD dopant film in the Alq3 emission layer ("undoped OLED"). The maximum brightness of the codoped and undoped OLEDs were 3207 cd/m2 and 1570 cd/m2, respectively. The wavelength of the maximum emission peak in the undoped sample was 527 nm and shifted slightly toward longer wavelength with the value of 540 nm for the codoped OLED sample. The maximum luminous efficiency of the undoped OLED was about 1.4 lm/W and increased to 7.0 lm/W for the codoped sample.

Efficient Organe Organic Light-Emitting Devices Using N-arylbenzinmidzoles as Blocking Layer

2013 ◽  
Vol 734-737 ◽  
pp. 2273-2277
Author(s):  
Hui Shan Yang ◽  
Li Shuang Wu
Keyword(s):  
Blue Light ◽  
Applied Voltage ◽  
Light Emission ◽  
Blocking Layer ◽  
Peak Efficiency ◽  
Yellow Light ◽  
Maximum Brightness ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light

A orange organic light-emitting device has been fabricated with a structure of ITO/m-MTDATA (45 nm)/NPB (8 nm)/ DPVBi:DCJTB 0.5 % (15 nm)/TPBi (x nm)/Alq3[(60-x) n /LiF (1 nm)/Al£¬where x=0, 4, 7 and 10, respectively. N-arylbenzinmidzoles (TPBi) was used as the excton-blocking layer resulting mixture of lights from DPVBi molecules (blue-light) and DCJTB (yellow-light) molecules, thereby producing orange light emission. The performance of device can be readily adjusted by only varying the thickness of the TPBi layer. The Commission Internationale de 1'Eclairage (CIE) coordinates of the device are largely insensitive to diffrent of the driving voltages. When the thickness of TPBi is 7 nm, the device exhibits peak efficiency of 6.16 cd/A at the applied voltage of 8 V, and the maximum brightness is 43310 cd/m2at 15 V, respectively.

White Electroluminescent Devices Using Polymer Blends

2003 ◽  
Vol 771 ◽  
Author(s):  
Do-Hoon Hwang ◽  
Jeong-Ik Lee ◽  
Chang-Hee Lee
Keyword(s):  
White Light ◽  
Light Emission ◽  
White Light Emission ◽  
Good Opportunity ◽  
Blend Ratio ◽  
Maximum Brightness ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Blend Films ◽  
Energy Transfers

AbstractWhite light-emitting devices were fabricated using the blends of blue, green, red emissive polymers of poly[9,9-(2'-ethylhexyl)fluorene] (PEHF), poly(9,9-dioctylfluorene-2,7-vinylene) (POFV), poly(2-(3',7'-dimethyloctyloxy)-5-methoxy-1,4-phenylene-1-cyanovinylene) (CNPPV) and poly(2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) (MEH-PPV). Inefficient energy transfers between the blue polymer and the green or the red polymer, which was observed in PL spectra of the blend films, provides a good opportunity to get white light emission due to better blend ratio controllability. The EL devices were fabricated with ITO/PEDOT/blend/Ca/Al configuration and good white light-emission was obtained for a certain blend ratio. The light-emission was observable from 4V and a maximum brightness of 400 cd/m2 was obtained with the device.

Synthesis and Electroluminescent Property of Bis{2-(naphtha [3,4]imidazol-2-Yl) Pyridinato} Magnesium

2012 ◽  
Vol 535-537 ◽  
pp. 2469-2474
Author(s):  
Shung Jim Yang ◽  
An Chi Yeh
Keyword(s):  
Emission Spectrum ◽  
Decomposition Temperature ◽  
Melting Transition ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Broad Maximum ◽  
Organic Light ◽  
Electroluminescent Property ◽  
Orange Region ◽  
Organic Light Emitting Devices

An emission material, bis{2-(naphtha [3,4]imidazol-2-yl) pyridinato} Magnesium (MgNIP) used for organic light emitting devices, has been synthesized. The decomposition temperature was observed at 510°C and no melting transition (Tm) of MgNIP was observed up to 400°C. The emission spectrum of organic emitting device using MgNIP as emitted layer exhibits a broad maximum at 531 nm. The color of the emitted light is in the orange region in the CIE coordinate of x = 0.46 y = 0.46.

scholarly journals Solution-Processed Efficient Blue Phosphorescent Organic Light-Emitting Diodes (PHOLEDs) Enabled by Hole-Transport Material Incorporated Single Emission Layer

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 554
Author(s):  
Taeshik Earmme
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light ◽  
Single Emission ◽  
Blue Phosphorescent

Solution-processed blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a single emission layer with small-molecule hole-transport materials (HTMs) are demonstrated. Various HTMs have been readily incorporated by solution-processing to enhance hole-transport properties of the polymer-based emission layer. Poly(N-vinylcarbazole) (PVK)-based blue emission layer with iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) triplet emitter blended with solution-processed 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) gave luminous efficiency of 21.1 cd/A at a brightness of 6220 cd/m2 with an external quantum efficiency (EQE) of 10.6%. Blue PHOLEDs with solution-incorporated HTMs turned out to be 50% more efficient compared to the reference device without HTMs. The high hole mobility, high triplet energy of HTM, and favorable energy transfer between HTM blended PVK host and FIrpic blue dopant were found to be important factors for achieving high device performance. The results are instructive to design and/or select proper hole-transport materials in solution-processed single emission layer.

Non-linear light emission of inorganic protonic diodes, H+LEDs

2021 ◽  
Vol 9 (9) ◽  
pp. 3052-3057
Author(s):  
Jerzy J. Langer ◽  
Ewelina Frąckowiak
Keyword(s):  
Light Emission ◽  
Stimulated Raman Scattering ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Light Pulses ◽  
Optical Effects ◽  
Non Linear ◽  
Intense Light ◽  
Light Beams ◽  
Intense Light Pulses

H+LEDs are light emitting devices based on a protonic p–n junction; now with no organic polymers. The unique are non-linear optical effects: collimated light beams and stimulated Raman scattering (SRS), observed while generating intense light pulses.

Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

2011 ◽  
Vol 1286 ◽  
Author(s):  
Th. C. Rosenow ◽  
S. Olthof ◽  
S. Reineke ◽  
B. Lüssem ◽  
K. Leo
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Sources ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Blue Emitters ◽  
Color Rendering ◽  
Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

Pyridine-Incorporated Dihexylquaterthiophene: A Novel Blue Emitter for Organic Light Emitting Diodes (OLEDs)

2012 ◽  
Vol 65 (9) ◽  
pp. 1244 ◽  
Author(s):  
Prashant Sonar ◽  
Sonsoles Garcia Santamaria ◽  
Ting Ting Lin ◽  
Alan Sellinger ◽  
Henk Bolink
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
High Yield ◽  
Device Performance ◽  
Host Matrix ◽  
Maximum Brightness ◽  
Light Emitting ◽  
Organic Light ◽  
Processing Techniques

The synthesis and characterisation of 2,5-bis(5′-hexyl-[2,2′-bithiophen]-5-yl)pyridine (Th4PY) and its use as a blue emitter in organic light emitting diodes (OLEDs) is reported. Th4PY was synthesised in high yield using a straightforward Suzuki coupling route with commercially available starting materials. As Th4PY is both soluble and has low molecular weight, blue OLEDs were fabricated using both spin-coating and vacuum deposition thin film processing techniques to study the effect of processing on device performance. OLED devices using a spin-coated layer consisting of 4′,4′′-tris(N-carbazolyl)triphenylamine (TCTA) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as a host matrix together with Th4PY as emitter exhibited highly efficient sky-blue emission with a low turn-on voltage of 3 V, a maximum brightness close to 15000 cd m–2 at 8 V, and a maximum luminous efficiency of 7.4 cd A–1 (6.3 lm W–1) with CIE coordinates of x = 0.212, y = 0.320. The device performance characteristics are compared using various matrices and processing techniques. The promising sky-blue OLED performance, solution processability, and ambient stability make Th4PY a promising blue emitter for application in OLEDs.

Sign in / Sign up

Export Citation Format

Share Document