Efficient organic manganese (II) bromide green-light-emitting diodes enabled by manipulating hole and electron transport layer

Author(s):  
Hyunsik Im ◽  
Atanu Jana ◽  
Vijaya Gopalan Sree ◽  
QIANKAI BA ◽  
Seong Chan Cho ◽  
...  

Lead-free, non-toxic transition metal-based phosphorescent organic–inorganic hybrid (OIH) compounds are promising for next-generation flat-panel displays and solid-state light-emitting devices. In the present study, we fabricate highly efficient phosphorescent green-light-emitting diodes...

2022 ◽  
Author(s):  
Nagarjuna Mude ◽  
Su Jeong Kim ◽  
Raju Lampande ◽  
Jang Hyuk Kwon

The efficiency and device lifetime of quantum dot light-emitting diodes (QLEDs) devices suffer due to charge unbalance issue resulting from excess electron injection from ZnO electron transport layer (ETL) to...


2012 ◽  
Vol 1511 ◽  
Author(s):  
Ippei Ishikawa ◽  
Keisuke Sakurai ◽  
Shuji Kiyohara ◽  
Taisuke Okuno ◽  
Hideto Tanoue ◽  
...  

ABSTRACTThe microfabrication technologiesfor organic light-emitting devices (OLEDs) are essential to the fabrication of the next generation of light-emitting devices. The micro-OLEDs fabricated by room-temperature curing nanoimprint lithography (RTC-NIL) using diamond molds have been investigated. However, light emissions from 10 μm-square-dot OLEDs fabricated by the RTC-NIL method have not been uniform. Therefore, we proposed the fabrication of micro-OLEDs by room-temperature curing nanocontact-print lithography (RTC-NCL) using the diamond-like carbon (DLC) mold. The DLC molds used in RTC-NCL were fabricated by an electron cyclotron resonance (ECR) oxygen ion shower with polysiloxane oxide mask in electron beam (EB) lithography technology. The mold patterns are square and rectangle dots which has 10 µm-width, 10 µm-width and50 µm-length, respectively. The height of the patterns is 500 nm. The DLC molds were used to form the insulating layer of polysiloxane in RTC-NCL. We carried out the RTC-NCL process using the DLC mold under the following optimum conditions: 0.1 MPa-pressure for coating DLC mold with polysiloxane film, 2.1 MPa-pressure for transferring polysiloxane from DLC mold pattern to indium tin oxide (ITO) glass substrate. We deposited N, N'-Diphenyl -N, N'-di (m-tolyl)benzidine (TPD) [40 nm-thickness] as hole transport layer / Tris(8-quinolinolato)aluminum (Alq3) [40 nm-thickness] as electron transport layer / Al [200 nm-thickness] as cathode on ITO glass substrateas anode in this order. We succeeded in formation of the insulating layer with square and rectangle dots which has 10 µm-width,10 µm-width and 50 µm-length, and operation of micro-OLEDs by RTC-NIL using DLC molds.


1992 ◽  
Vol 247 ◽  
Author(s):  
Paul L. Burn ◽  
A. B. Holmes ◽  
A. Kraft ◽  
A. R. Brown ◽  
D. D. C. Bradley ◽  
...  

ABSTRACTStudies of the effect of different electrode combinations on the device characteristics of simple three layer light-emitting diodes (LEDs) prepared with poly(ρ-phenylenevinylene) (PPV) as the emissive layer sandwiched between two metal contacts have shown that it is generally more difficult to inject electrons than holes. In order to improve the efficiency of such devices it is, therefore, necessary to develop methods to enhance the injection of electrons and we illustrate here one example where we have successfully achieved this by the introduction of a further, electron transport, layer. The result is an eight fold increase in efficiency over our best three layer PPV devices. The efficiency is also dependent on the details of the polymer electronic structure and using a family of copolymers we have been able to produce enhancements in efficiency to values of up to 30 times that of the corresponding PPV devices. Variations in the polymer electronic structure also affect the colour of emission and the same family of copolymers allow control of emission colour from blue/green to orange/red. Supramolecular control of the copolymer electronic structure can be achieved by lithographic patterning and we show that it is possible to produce regions within a single polymer film that possess different π-π* energy gaps.


2018 ◽  
Vol 6 (26) ◽  
pp. 6996-7002 ◽  
Author(s):  
Heyong Wang ◽  
Hongling Yu ◽  
Weidong Xu ◽  
Zhongcheng Yuan ◽  
Zhibo Yan ◽  
...  

Solution-processed tin dioxide is employed as an electron transport layer in n–i–p-structured perovskite light-emitting diodes realizing an EQE of 7.9%.


2019 ◽  
Vol 9 (21) ◽  
pp. 4539 ◽  
Author(s):  
Seongkeun Oh ◽  
Jiwan Kim

The present work shows the effect of the ZnO layer morphology on inverted quantum dot light-emitting diodes (QLEDs) using different spin-coating processes. In the inverted structure of ITO/ZnO/QDs/CBP/MoO3/Al, ZnO nanoparticles were used as the electron transport layer. The utilization of a two-step spin-coating process to deposit a ZnO layer on a patterned ITO glass substrate resulted in an increase in the surface roughness of the ZnO layer and a decrease in the luminance of the QLEDs. However, the current efficiency of the device was enhanced by more than two-fold due to the reduced current density. Optimization of the ZnO spin-coating process can efficiently improve the optical and electrical properties of QLEDs.


Sign in / Sign up

Export Citation Format

Share Document