scholarly journals Phosphorescent Molecularly Doped Light-Emitting Diodes with Blended Polymer Host and Wide Emission Spectra

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Jun Wang ◽  
Jun Gou ◽  
Weizhi Li

Stable green light emission and high efficiency organic devices with three polymer layers were fabricated using bis[2-(4′-tert-butylphenyl)-1-phenyl-1H-benzoimidazole-N,C2′] iridium(III) (acetylacetonate) doped in blended host materials. The 1 wt% doping concentration showed maximum luminance of 7841 cd/cm2at 25.6 V and maximum current efficiency of 9.95 cd/A at 17.2 V. The electroluminescence spectra of devices indicated two main peaks at 522 nm and 554 nm coming from phosphor dye and a full width at half maximum (FWHM) of 116 nm. The characteristics of using blended host, doping iridium complex, emission spectrum, and power efficiency of organic devices were investigated.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jun Wang ◽  
Weizhi Li

High efficiency white organic light emission devices were demonstrated with phosphor material dye bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2′]iridium (acetylacetonate) and ultrathin layer structure. The ultra thin layer be composed of 4,4′-bis[N-1-naphthyl-N-phenyl-amino]biphenyl (NPB) or 4,4′-N,N′-dicarbazole-biphenyl : NPB mixed layer with blue light emission. The emission spectra of devices could be adjusted by different phosphor doping concentrations and ultra thin layer structure. Warm white light emitting device could be obtained with 5 wt% doping concentration and power efficiency of 9.93 lm/W at 5 V. Pure white light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.30) and external quantum efficiency of 4.49% could be achieved with ultra thin layer device structure and 3 wt% phosphor doped device.


2021 ◽  
Vol 119 (24) ◽  
pp. 241103
Author(s):  
Miao Wang ◽  
Yu Lin ◽  
Jue-Min Yi ◽  
De-Yao Li ◽  
Jian-Ping Liu ◽  
...  

2016 ◽  
Vol 24 (13) ◽  
pp. 15071 ◽  
Author(s):  
Cunlong Li ◽  
Zhigang Zang ◽  
Weiwei Chen ◽  
Zhiping Hu ◽  
Xiaosheng Tang ◽  
...  

Nanoscale ◽  
2019 ◽  
Vol 11 (47) ◽  
pp. 22899-22906 ◽  
Author(s):  
Miao He ◽  
Chunyun Wang ◽  
Jingzhou Li ◽  
Jiang Wu ◽  
Siwei Zhang ◽  
...  

All-inorganic perovskite CsPbBr3–Cs4PbBr6 composite nanocrystals (NCs) were synthesized via a convenient solution process without inert gas protection and systematically studied as green phosphors for light emitting diode (LED) applications.


1992 ◽  
Vol 283 ◽  
Author(s):  
X. Y. Hou ◽  
G. Shi ◽  
W. Wang ◽  
F. L. Zhang ◽  
P. H. Hao ◽  
...  

ABSTRACTThrough a post treatment of light emitting porous silicon in boilingwater, a large blue shift of its photoluminescence (PL) spectrum hasbeen observed and a stable blue-green light emission at the peak wavelength down to 500 nm is achieved. The effect of boiling water treatment is suggested to be a kind of oxidation, which could reduce thesize of the Si column, fill up some micropores and strengthen the Siskeleton. The photoluminescence microscopic observation shows that the surface of blue light emitting porous silicon is composed of manysmall uniformly light-emitting domains at the size of several tens of μm. Fourier transform infrared reflection (FTIR) measurements show that the formation of Si-H bonds is not responsible for the visible luminescence in the very thin Si wires.


Author(s):  
Chang-Qing Jing ◽  
Qi-Long Liu ◽  
Cheng-Hao Zhao ◽  
Yan-Yu Zhao ◽  
Cheng-Yang Yue ◽  
...  

New 1D halide of [TMPDA]2Pb3Br10 displays a sharp green light emission at 526 nm with FWHM of 25 nm, PLQY of 71.95% and color purity of 91.1%, which achieves the Rec. 2020 standard, and represents the purest green light emitting 1D halide up to date.


1992 ◽  
Vol 281 ◽  
Author(s):  
Y. Lansari ◽  
Z. Yu ◽  
J. Ren ◽  
C. Boney ◽  
J. W. Cook ◽  
...  

ABSTRACTIntegrated heterostructure devices (IHDs) comprised of II-VI materials in multi-layered structures for light emitting diode (LED) and laser diode (LD) applications are described. These IHDs combine a light emission multilayer structure (wide band gap II-VI layers) with an abrupt or graded heterostructure (comprised of narrow band gap II-VI layers) for improved ohmic contact to the upper p-type layer of the light emitting structure.


2002 ◽  
Vol 744 ◽  
Author(s):  
Jianhua Zhao ◽  
Aihua Wang ◽  
Thorsten Trupke ◽  
Martin A. Green

ABSTRACTA high power conversion efficiency above 1% from a bulk crystalline silicon (c-Si) light-emitting diode (LED) has been demonstrated at near room temperature. These devices are based on normally weak one- and two-phonon assisted sub-bandgap light emission processes. Their improved performance results from device designs that take advantage of enhanced light absorption by a light trapping scheme which was developed for high efficiency silicon solar cells, and from reducing scope for parasitic non-radiative recombination within the diode. Each feature individually is shown to improve efficiency by a factor of ten, accounting for an improvement by factor of one hundred compared to baseline devices.Also demonstrated is a greatly improved band-edge light emission and detection using bulk c-Si diodes. A bulk c-Si LED is combined with a similar diode used as a detector that collects the light emitted with a high quantum collection efficiency of 33%, to produce a silicon to silicon optically coupled system that demonstrates 0.18% coupling quantum efficiency. The crystalline silicon LED demonstrates similarly high performance at very low power levels, where it has even higher power efficiency than a high efficiency GaAlAs LED.


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