Chemiluminescence of organic peroxide decomposition

1963 ◽  
Vol 275 (1363) ◽  
pp. 465-468 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Surface Effect ◽  
Blue Emission ◽  
Organic Peroxide ◽  
Liquid Volume ◽  
Light Emitting ◽  
Peroxide Decomposition ◽  
Organic Hydroperoxides

The thermal decomposition of organic hydroperoxides in solution gives rise to weak chemiluminescence effects. One emission, which has a maximum at a wavelength longer than 5500 Å, seems chiefly, if not entirely, a surface effect. With hydroperoxides having aromatic nuclei a blue emission from the liquid volume is observed. The nature of the light-emitting processes is discussed.

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.

scholarly journals Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chenhui Wang ◽  
Dengbao Han ◽  
Junhui Wang ◽  
Yingguo Yang ◽  
Xinyue Liu ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Light Emitting ◽  
Mixed Ligands ◽  
Dimension Control ◽  
Nanocrystal Films ◽  
Width Distribution ◽  
Quantum Well Width

AbstractIn the field of perovskite light-emitting diodes (PeLEDs), the performance of blue emissive electroluminescence devices lags behind the other counterparts due to the lack of fabrication methodology. Herein, we demonstrate the in situ fabrication of CsPbClBr2 nanocrystal films by using mixed ligands of 2-phenylethanamine bromide (PEABr) and 3,3-diphenylpropylamine bromide (DPPABr). PEABr dominates the formation of quasi-two-dimensional perovskites with small-n domains, while DPPABr induces the formation of large-n domains. Strong blue emission at 470 nm with a photoluminescence quantum yield up to 60% was obtained by mixing the two ligands due to the formation of a narrower quantum-well width distribution. Based on such films, efficient blue PeLEDs with a maximum external quantum efficiency of 8.8% were achieved at 473 nm. Furthermore, we illustrate that the use of dual-ligand with respective tendency of forming small-n and large-n domains is a versatile strategy to achieve narrow quantum-well width distribution for photoluminescence enhancement.

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.

scholarly journals Efficient Exciplex-Based Deep-Blue Organic Light-Emitting Diodes Employing a Bis(4-fluorophenyl)amine-Substituted Heptazine Acceptor

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5568
Author(s):  
Jie Li ◽  
Heqi Gong ◽  
Jincheng Zhang ◽  
Hui Liu ◽  
Li Tao ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Deep Blue ◽  
Photoluminescence Quantum Yield ◽  
Organic Light ◽  
High Maximum ◽  
Exciplex Emission ◽  
Amine Groups

The realization of a deep-blue-emitting exciplex system is a herculean task in the field of organic light-emitting diodes (OLEDs) on account of a large red-shifted and broadened exciplex emission spectrum in comparison to those of the corresponding single compounds. Herein, 2,5,8-tris(di(4-fluorophenyl)amine)-1,3,4,6,7,9,9b-heptaazaphenalene (HAP-3FDPA) was designed as an electron acceptor by integrating three bis(4-fluorophenyl)amine groups into a heptazine core, while 1,3-di(9H-carbazol-9-yl)benzene (mCP) possessing two electron-donating carbazole moieties was chosen as the electron donor. Excitingly, the exciplex system of 8 wt% HAP-3FDPA:mCP exhibited deep-blue emission and a high photoluminescence quantum yield of 53.2%. More importantly, an OLED containing this exciplex system as an emitting layer showed deep-blue emission with Commission Internationale de l’Eclairage coordinates of (0.16, 0.12), a peak luminance of 15,148 cd m−2, and a rather high maximum external quantum efficiency of 10.2% along with a low roll-off. This study not only reports an efficient exciplex-based deep-blue emitter but also presents a feasible pathway to construct highly efficient deep-blue OLEDs based on exciplex systems.

Dibenzo[f,h]furo[2,3-b]quinoxaline-based molecule scaffold as deep blue fluorescence materials for organic light-emitting diodes

2021 ◽  
Author(s):  
XinYe Wang ◽  
Yuan Wu ◽  
ChuanMing Wu ◽  
Yixiang Li ◽  
Dongdong Wang ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Molecular Scaffolds ◽  
Blue Fluorescence ◽  
Light Emitting ◽  
Highly Efficient ◽  
Deep Blue ◽  
Organic Light

Two novel molecular scaffolds, dibenzo[f,h]furo[2,3-b]quinoxaline (diBFQ) and its derivative, 3,6-bis(4-isopropylphenyls)-11-phenyldibenzo[f,h]furo[2,3-b]quinoxaline (dP-diBFQ), and furo[2',3':5,6]pyrazino[2,3-f][1,10]phenanthroline (FPPhen), were designed and syn-thesized for highly efficient pure and deep blue emission. The unsubstituted molecule scaffold...

A new langbeinite-type phosphate K2GdHf(PO4)3: synthesis, crystal structure, band structure and luminescence properties

2020 ◽  
Vol 76 (8) ◽  
pp. 771-778
Author(s):  
Hua Nan ◽  
Li Chen ◽  
Rui-Juan Zhang ◽  
Dan Zhao
Keyword(s):  
Optical Transition ◽  
Blue Emission ◽  
Large Family ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Light Emitting ◽  
Direct Band ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Langbeinite-type compounds are a large family that include phosphates, sulfates and arsenates, and which are accompanied by interesting physical properties. This work reports a new disordered langbeinite-type compound, K2GdHf(PO4)3 [dipotassium gadolinium hafnium tris(phosphate)], and its structure as determined by single-crystal X-ray diffraction. Theoretical studies reveal that K2GdHf(PO4)3 is an insulator with a direct band gap of 4.600 eV and that the optical transition originates from the O-2p→Hf-5d transition. A Ce3+-doped phosphor, K2Gd0.99Ce0.01Hf(PO4)3, was prepared and its luminescence properties studied. With 324 nm light excitation, a blue emission band was observed due to the 5d 1→4f 1 transition of Ce3+. The average luminescence lifetime was calculated to be 5.437 µs and the CIE chromaticity coordinates were (0.162, 0.035). One may expect that K2Gd0.99Ce0.01Hf(PO4)3 can be used as a good blue phosphor for three-colour white-light-emitting diodes (WLEDs).

Efficient deep-blue non-doped organic light-emitting diode with improved roll-off of efficiency based on hybrid local and charge-transfer excited state

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 70085-70090 ◽  
Author(s):  
Haichao Liu ◽  
Qing Bai ◽  
Weijun Li ◽  
Yachen Guo ◽  
Liang Yao ◽  
...  
Keyword(s):  
Excited State ◽  
High Efficiency ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Deep Blue ◽  
Organic Light ◽  
Slow Roll ◽  
Donor Acceptor

Acceptor–donor–acceptor triphenylamine–phenanthroimidazole derivate (TPA–2PPI) servers as an emitter, whose device exhibits deep-blue emission, high efficiency and slow roll-off of efficiency.

scholarly journals Optimal LED Wavelength Composition for the Production of High-Quality Watermelon and Interspecific Squash Seedlings Used for Grafting

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 870 ◽  
Author(s):  
Filippos Bantis ◽  
Athanasios Koukounaras ◽  
Anastasios S. Siomos ◽  
Kalliopi Radoglou ◽  
Christodoulos Dangitsis
Keyword(s):  
Blue Emission ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Stem Diameter ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Shoot Dry Weight

Watermelon is cultivated worldwide and is mainly grafted onto interspecific squash rootstocks. Light-emitting diodes (LEDs) can be implemented as light sources during indoor production of both species and their spectral quality is of great importance. The objective of the present study was to determine the optimal emission of LEDs with wide wavelength for the production of watermelon and interspecific squash seedlings in a growth chamber. Conditions were set at 22/20 °C temperature (day/night), 16 h photoperiod, and 85 ± 5 μmol m−2 s−1 photosynthetic photon flux density. Illumination was provided by fluorescent (FL, T0) lamps or four LEDs (T1, T2, T3, and T4) emitting varying wide spectra. Watermelon seedlings had greater shoot length, stem diameter, cotyledon area, shoot dry weight-to-length (DW/L) ratio, and Dickson’s quality index (DQI) under T1 and T3, while leaf area and shoot dry weight (DW) had higher values under T1. Interspecific squash seedlings had greater stem diameter, and shoot and root DW under T1 and T3, while leaf and cotyledon areas were favored under T1. In both species, T0 showed inferior development. It could be concluded that a light source with high red emission, relatively low blue emission, and a red:far-red ratio of about 3 units seems ideal for the production of high-quality watermelon (scion) and interspecific squash (rootstock) seedlings.

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