scholarly journals Effect of Optical and Morphological Control of Single-Structured LEC Device

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 843
Author(s):  
Woo Jin Jeong ◽  
Jong Ik Lee ◽  
Hee Jung Kwak ◽  
Jae Min Jeon ◽  
Dong Yeol Shin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Roughness ◽  
Surface Properties ◽  
High Efficiency ◽  
High Surface ◽  
Reduction Rate ◽  
Operating Characteristics ◽  
Emission Layer ◽  
Light Emitting ◽  
Stable Operating

We investigated the performance of single-structured light-emitting electrochemical cell (LEC) devices with Ru(bpy)3(PF6)2 polymer composite as an emission layer by controlling thickness and heat treatment. When the thickness was smaller than 120–150 nm, the device performance decreased because of the low optical properties and non-dense surface properties. On the other hand, when the thickness was over than 150 nm, the device had too high surface roughness, resulting in high-efficiency roll-off and poor device stability. With 150 nm thickness, the absorbance increased, and the surface roughness was low and dense, resulting in increased device characteristics and better stability. The heat treatment effect further improved the surface properties, thus improving the device characteristics. In particular, the external quantum efficiency (EQE) reduction rate was shallow at 100 °C, which indicates that the LEC device has stable operating characteristics. The LEC device exhibited a maximum luminance of 3532 cd/m2 and an EQE of 1.14% under 150 nm thickness and 100 °C heat treatment.

Improvement of efficiency and its roll-off at high brightness in white organic light-emitting diodes by strategically managing triplet excitons in the emission layer

2018 ◽  
Vol 6 (40) ◽  
pp. 10793-10803 ◽  
Author(s):  
Shian Ying ◽  
Dezhi Yang ◽  
Xianfeng Qiao ◽  
Yanfeng Dai ◽  
Qian Sun ◽  
...  
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
High Brightness ◽  
Light Emitting ◽  
Organic Light ◽  
Low Efficiency ◽  
Triplet Excitons

High-performance WOLEDs realizing high efficiency and low efficiency roll-off simultaneously were achieved by strategically managing triplet excitons in the emission layer.

Influence of Processing Factors on the Surface Properties of Zirconia Coatings Fabricated by Room Temperature Spray Process

2020 ◽  
Vol 20 (7) ◽  
pp. 4152-4157
Author(s):  
Jeong Jun Kim ◽  
Jong Kook Lee
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Surface Properties ◽  
Room Temperature ◽  
Coating Layer ◽  
High Surface ◽  
Phase Changes ◽  
Deposition Cycle ◽  
Implant Surface ◽  
Processing Factors

Highly roughened surfaces on dental implants enhance the bone-bonding ability and in vivo cell adhesion on the implant surface. In this study, zirconia substrates were coated by powder coating using room temperature spray processing to improve their surface properties. Processing factors (particle size of the starting powder, number of repetitions of the deposition cycle, and spraying distance) were controlled to form a dense coating layer with high surface roughness on the zirconia substrate. Starting zirconia powders for coating were heat-treated at high temperature to control the particle size and kinetic energy. The coating layer fabricated from starting powder with a particle size of about 1.52 μm shows a homogeneous and dense microstructure, and it has a maximum surface roughness about 0.37 μm. The surface roughness of the film coatings increased with the number of times that the deposition cycle was repeated. No phase changes between the starting powder and the coating layer were observed, and all of the materials show identical tetragonal phases.

High efficiency and simplified white organic light-emitting diode based on a single-host emission layer

2016 ◽  
Vol 220 ◽  
pp. 329-333 ◽  
Author(s):  
Runda Guo ◽  
Shiming Zhang ◽  
Shouzhen Yue ◽  
Pingrui Yan ◽  
Yukun Wu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diode ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Single Host

scholarly journals Surface properties of poplar wood after heat treatment, resin impregnation, or both modifications

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7562-7577
Author(s):  
Shuai Cao ◽  
Jiabin Cai ◽  
Meihui Wu ◽  
Nan Zhou ◽  
Zhenhua Huang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Roughness ◽  
Surface Properties ◽  
Urea Formaldehyde ◽  
Formaldehyde Resin ◽  
Poplar Wood ◽  
Resin Impregnation ◽  
Heat Treated ◽  
Populus Tomentosa Carr ◽  
Heat Treatment Sample

To investigate the surface properties of different modified poplar (Populus tomentosa Carr.) wood samples, the color, surface roughness, and wettability of untreated poplar wood (control) and poplar modified via heat treatment, resin impregnation, and impregnation combined heat treatment were analyzed and compared in this study. The impregnant used in the test was a modified urea-formaldehyde resin with a low molecular weight and low viscosity. The results showed that the lightness of the samples was sorted in order as follows: the control was lighter than the resin impregnated sample, which was lighter than the impregnation combined heat treatment sample, which was lighter than the heat treatment sample. The surface of the control samples was relatively smooth, while after the impregnation, heat, and impregnation combined heat treatments, the Ra and Rz values increased, which indicated increased surface roughness due to the modifications. Among them, the heat-treated samples had the roughest surface, and the surface roughness of the impregnation combined heat treated samples at 160 °C had no major difference from the resin impregnated sample. The wettability of the samples decreased after heat treatment and increased after impregnation combined heat treatment. It was concluded that after the modification treatments, the color of the wood became darker, and the surface roughness and hydrophobicity increased.

High-Efficiency Red Perovskite Light-emitting Diodes Based on Collaborative Optimization of Emission Layer and Transport Layers

2021 ◽  
Author(s):  
Hongfei Shi ◽  
Zhibin Wang ◽  
Huanyu Ma ◽  
Haoran Jia ◽  
Fuzhi Wang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Collaborative Optimization ◽  
Flat Panel Displays ◽  
Flat Panel ◽  
Emission Layer ◽  
Light Emitting ◽  
Metal Halide Perovskite ◽  
New Type ◽  
Halide Perovskite

Metal halide perovskite light-emitting diodes (PeLEDs) is a new type of electroluminescent device with wide application in flat-panel displays and solid-state lighting. The charge recombination at the electrode interfaces and...

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