Long-wavelength red light emission from TV and photosensitive seizures

2001 ◽  
Vol 103 (2) ◽  
pp. 114-119 ◽  
Author(s):  
Y. Takahashi ◽  
T. Ozawa ◽  
H. Nakamura ◽  
S. Yamada ◽  
H. Okamoto ◽  
...  
Keyword(s):  
Light Emission ◽  
Red Light ◽  
Long Wavelength

First-principles identification of VI+Cui defect cluster in cuprous iodide: origin of red light photoluminescence

2022 ◽  
Author(s):  
Dingrong Liu ◽  
Zenghua Cai ◽  
Yu-Ning Wu ◽  
Shiyou Chen
Keyword(s):  
First Principles ◽  
Light Emission ◽  
Red Light ◽  
Defect Cluster ◽  
Intrinsic Point Defect ◽  
Long Wavelength ◽  
Type Semiconductor ◽  
Display Technology ◽  
Wavelength Emission ◽  
P Type

Abstract The γ-phase Cuprous Iodide (CuI) emerges as a promising transparent p-type semiconductor for next-generation display technology because of its wide direct band gap, intrinsic p-type conductivity, and high carrier mobility. Two main peaks are observed in its photoluminescence (PL). One is short wavelength (410-430 nm) emission, which is well attributed to the electronic transitions at Cu vacancy, whereas the other long wavelength emission (680-720 nm) has not been fully understood. In this paper, through first-principles simulations, we investigate the formation energies and emission line shape for various defects, and discover that the intrinsic point defect cluster V_I+Cu_i^(2+) is the source of the long wavelength emission. Our finding is further supported by the prediction that the defect concentration decreases dramatically as the chemical condition changes from Cu-rich to I-rich, explaining the significant reduction in the red light emission if CuI is annealed in abundant I environment.

scholarly journals Incommensurately Modulated Crystal Structure and Photoluminescence Properties of Eu2O3- and P2O5-Doped Ca2SiO4 Phosphor

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 58
Author(s):  
Hiromi Nakano ◽  
Shota Ando ◽  
Konatsu Kamimoto ◽  
Yuya Hiramatsu ◽  
Yuichi Michiue ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Light Emission ◽  
Red Light ◽  
Basic Unit ◽  
Β Phase ◽  
Stacking Order ◽  
Cell Dimensions ◽  
Incommensurate Modulation ◽  
Unit Cell Dimensions ◽  
Identical Chemical Composition

We prepared four types of Eu2O3- and P2O5-doped Ca2SiO4 phosphors with different phase compositions but identical chemical composition, the chemical formula of which was (Ca1.950Eu3+0.013☐0.037)(Si0.940P0.060)O4 (☐ denotes vacancies in Ca sites). One of the phosphors was composed exclusively of the incommensurate (IC) phase with superspace group Pnma(0β0)00s and basic unit-cell dimensions of a = 0.68004(2) nm, b = 0.54481(2) nm, and c = 0.93956(3) nm (Z = 4). The crystal structure was made up of four types of β-Ca2SiO4-related layers with an interlayer. The incommensurate modulation with wavelength of 4.110 × b was induced by the long-range stacking order of these layers. When increasing the relative amount of the IC-phase with respect to the coexisting β-phase, the red light emission intensity, under excitation at 394 nm, steadily decreased to reach the minimum, at which the specimen was composed exclusively of the IC-phase. The coordination environments of Eu3+ ion in the crystal structures of β- and IC-phases might be closely related to the photoluminescence intensities of the phosphors.

Tunable luminescence and white light emission of porphyrin-zinc coordination assemblies

2018 ◽  
Vol 22 (09n10) ◽  
pp. 821-830 ◽  
Author(s):  
Zheng Wang ◽  
Jian-Hua Zhang ◽  
Cheng-Yi Zhu ◽  
Shao-Yun Yin ◽  
Mei Pan
Keyword(s):  
White Light ◽  
Light Emission ◽  
Three Dimensional ◽  
White Light Emission ◽  
Molar Ratio ◽  
Excitation Wavelength ◽  
Temperature Dependent ◽  
Long Wavelength ◽  
Linear Formula ◽  
Zinc Coordination

Bipodal ligand 5,15-bis(4-carboxyphenyl) porphyrin (H[Formula: see text]DCPP) was designed and synthesized. By adjusting the molar ratio of H[Formula: see text]DCPP, ancillary ligand 4,4-bipyridine (bpy) and zinc acetate salts, three novel coordination assemblies, namely, zero-dimensional dimeric [Zn[Formula: see text](H[Formula: see text]DCPP)[Formula: see text] ·bpy] ·4H[Formula: see text]O ·4DMF (Zn-D), two-dimensional polymeric {[Zn[Formula: see text](DCPP) ·bpy[Formula: see text] ·H[Formula: see text]O ·DMF[Formula: see text]] ·solvent}[Formula: see text] (Zn-2D), and three-dimensional polymeric [Zn[Formula: see text](DCPP) ·bpy[Formula: see text]][Formula: see text] (Zn-3D) were assembled. Due to the delicate integration of multiple chromophores in the coordination space combining bpy, DCPP and MLCT emissions together, photoluminescence (PL) of the three porphyrin-zinc coordination assemblies differ from each other and color tone is tunable from blue to orange with changes of the excitation wavelength. In particular, white light emission (WLE) can be observed by the excitation of 270 to 290 nm, representing the first examples of single component WLE compounds based on porphyrin ligands. Furthermore, temperature-dependent luminescence results in a linear [Formula: see text]–[Formula: see text] relationship in Zn-2D and Zn-3D assemblies, applicable for long wavelength red-emitting thermometers.

Blue, Green, and Red Light Emission of 1,8-Carbazole-based Conjugated Polymers

2010 ◽  
Vol 39 (3) ◽  
pp. 168-169 ◽  
Author(s):  
Tsuyoshi Michinobu ◽  
Haruka Osako ◽  
Kimie Murata ◽  
Kiyotaka Shigehara
Keyword(s):  
Conjugated Polymers ◽  
Light Emission ◽  
Red Light

scholarly journals Evidences from Action Spectra for a Specific Participation of Chlorophyll b in Photosynthesis

1960 ◽  
Vol 43 (4) ◽  
pp. 723-736 ◽  
Author(s):  
Jack Myers ◽  
C. S. French
Keyword(s):  
Oxygen Evolution ◽  
Platinum Electrode ◽  
Red Light ◽  
Chlorophyll B ◽  
Long Wavelength ◽  
Action Spectra ◽  
Rate Of Photosynthesis ◽  
Measurable Rate ◽  
Low Levels ◽  
Light Beams

Rate of oxygen evolution in photosynthesis was measured as the current from a polarized platinum electrode covered by a thin layer of Chlorella. The arrangement gave a reproducibly measurable rate of photosynthesis proportional to light intensity at the low levels used and gave rapid response to changes in illumination. Two phenomena have been explored. The Emerson effect was observed as an enhancement of photosynthesis in long wavelength red light (700 mµ) when shorter wavelengths were added. Two light beams of wavelengths 653 and 700 mµ when presented together gave a photosynthetic rate about 25 per cent higher than the sum of the rates obtained separately. Large and reproducible transients in rate of oxygen evolution were observed accompanying change in illumination between two wavelengths adjusted in intensity to support equal steady rates of photosynthesis. The transients were found not to be specifically related to long wavelength red light. Both enhancement and the transients have identical action spectra which are interpreted as demonstrating a specific photochemical participation of chlorophyll b.

High-Efficiency Red-Light Emission from Polyfluorenes Grafted with Cyclometalated Iridium Complexes and Charge Transport Moiety

2003 ◽  
Vol 125 (3) ◽  
pp. 636-637 ◽  
Author(s):  
Xiwen Chen ◽  
Jin-Long Liao ◽  
Yongmin Liang ◽  
M. O. Ahmed ◽  
Hao-En Tseng ◽  
...  
Keyword(s):  
Charge Transport ◽  
High Efficiency ◽  
Light Emission ◽  
Red Light ◽  
Iridium Complexes

Carbon dots with efficient solid-state red-light emission through the step-by-step surface modification towards light-emitting diodes

2018 ◽  
Vol 47 (11) ◽  
pp. 3811-3818 ◽  
Author(s):  
Jinyang Zhu ◽  
Xue Bai ◽  
Xu Chen ◽  
Zhifeng Xie ◽  
Yongsheng Zhu ◽  
...  
Keyword(s):  
Surface Modification ◽  
Solid State ◽  
Carbon Dots ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Red Light ◽  
Light Emitting

Carbon dots with efficient solid-state red-light emission through step-by-step surface modification.

Facile synthesis of yellow fluorescent carbon dots for highly sensitive sensing of cobalt ions and biological imaging

2019 ◽  
Vol 11 (32) ◽  
pp. 4077-4083 ◽  
Author(s):  
Min Tian ◽  
Yaoming Liu ◽  
Yingte Wang ◽  
Yong Zhang
Keyword(s):  
Light Emission ◽  
Biological Imaging ◽  
Cobalt Ions ◽  
Long Wavelength ◽  
Scattering Effects ◽  
Highly Sensitive ◽  
Penetration Ability ◽  
Weak Light ◽  
Fluorescent Carbon Dots ◽  
Wavelength Light

Long-wavelength light emission has been garnering extensive attention in terms of strong tissue penetration ability and weak light scattering effects.

scholarly journals Bis-Tridendate Ir(III) Polymer-Metallocomplexes: Hybrid, Main-Chain Polymer Phosphors for Orange–Red Light Emission

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2976
Author(s):  
Konstantinos Andrikopoulos ◽  
Charalampos Anastasopoulos ◽  
Joannis K. Kallitsis ◽  
Aikaterini K. Andreopoulou
Keyword(s):  
Main Chain ◽  
Light Emission ◽  
Red Light ◽  
Molecular Complexes ◽  
Hydroxyl Groups ◽  
Iridium Complexes ◽  
Light Emitters ◽  
Chain Polymer ◽  
Molecular Weights ◽  
Pyridine Moiety

In this work, hybrid polymeric bis-tridentate iridium(III) complexes bearing derivatives of terpyridine (tpy) and 2,6-di(phenyl) pyridine as ligands were successfully synthesized and evaluated as red-light emitters. At first, the synthesis of small molecular bis-tridendate Ir(III) complexes bearing alkoxy-, methyl-, or hydroxy-functionalized terpyridines and a dihydroxyphenyl-pyridine moiety was accomplished. Molecular complexes bearing two polymerizable end-hydroxyl groups and methyl- or alkoxy-decorated terpyridines were copolymerized with difluorodiphenyl-sulphone under high temperature polyetherification conditions. Alternatively, the post-polymerization complexation of the terpyridine-iridium(III) monocomplexes onto the biphenyl-pyridine main chain homopolymer was explored. Both cases afforded solution-processable metallocomplex-polymers possessing the advantages of phosphorescent emitters in addition to high molecular weights and excellent film-forming ability via solution casting. The structural, optical, and electrochemical properties of the monomeric and polymeric heteroleptic iridium complexes were thoroughly investigated. The polymeric metallocomplexes were found to emit in the orange–red region (550–600 nm) with appropriate HOMO and LUMO levels to be used in conjunction with blue-emitting hosts. By varying the metal loading on the polymeric backbone, the emitter’s specific emission maxima could be successfully tuned.

Sign in / Sign up

Export Citation Format

Share Document