Mn4+ Activated Deep Red Emitting Perovskite Type Phosphors for Horticulture Lighting

2021 ◽  
Vol 1167 ◽  
pp. 57-66
Author(s):  
Muhammad Khurram ◽  
Florian Baur ◽  
Thomas Juestel
Keyword(s):  
Emission Spectra ◽  
Host Lattice ◽  
Luminescence Spectra ◽  
Quenching Temperature ◽  
Light Emitting ◽  
Thermally Activated ◽  
Host Materials ◽  
Colour Rendering ◽  
Perovskite Type ◽  
Pl Quenching

Red emitting Mn4+ doped oxides are a promising class of materials to improve the colour rendering and luminous efficacy of phosphor-converted light-emitting diodes (pcLEDs). For pcLEDs, the optical properties are crucial w.r.t commercial acceptance. In this work, luminescence spectra and decay curves of Sr2YNbO6, Sr2YTaO6 and Sr2LaNbO6 have been recorded, other Mn4+ doped phosphors show that quenching occurs through thermally activated crossover between the 4T2 excited state and 4A2 ground state. The quenching temperature can be optimized by designing the host lattice in which Mn4+ has a high 4T2 state energy. The main target is to study the influence of the above-mentioned host materials on the emission spectra, PL quenching, and quantum yield of the deep red Mn4+ ion. The present study provides detailed insights into temperature and concentration quenching of Mn4+ emission and can be used to realize superior narrow-band red Mn4+ phosphors for horticultural lighting.

Spatially optimized quaternary phosphine oxide host materials for high-efficiency blue phosphorescence and thermally activated delayed fluorescence organic light-emitting diodes

2015 ◽  
Vol 3 (43) ◽  
pp. 11385-11396 ◽  
Author(s):  
Dongxue Ding ◽  
Zhen Zhang ◽  
Ying Wei ◽  
Pengfei Yan ◽  
Hui Xu
Keyword(s):  
Phosphine Oxide ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Spatial Optimization ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Host Materials

Spatial optimization of host materials for highly efficient blue organic light-emitting diodes was rationally performed on the basis of a series of ternary and quaternary phosphine oxide materials.

Noble Dibenzothiophene-Based Bipolar Hosts for Blue Organic Light-Emitting Diodes Using Thermally Activated Delayed Fluorescence

2020 ◽  
Vol 20 (11) ◽  
pp. 7191-7195
Author(s):  
JaMin Lee ◽  
Sae Won Lee ◽  
Young Sik Kim
Keyword(s):  
Dft Calculations ◽  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Host Materials ◽  
Td Dft

Novel thermally activated delayed fluorescence (TADF) host materials for blue electrophosphores-cence were designed by combining the electron acceptor dibenzothiophene (DBT) unit and the electron donor acridine derivatives into a single molecular unit by density functional theory (DFT). Depending on the optimal charge transfer, DFT and time-dependent DFT (TD-DFT) calculations for the ground state were performed to obtain the energy of the singlet (S1) and triplet (T1) excited states of the TADF material for Hartree-Fock percentage of TD-DFT. The sufficiently large separation between the HOMO and LUMO resulted in a small difference in energy (ΔEST) between the S1 and T1 states using DFT and TD-DFT calculations. The host molecules retained high triplet energy and showed great potential for use in blue organic light-emitting diodes (OLED). The results showed that these molecules are a good TADF host materials because they have a low barrier to hole and electron injection with a balanced charge transporting property for both holes and electrons, and a small ΔEST.

Photoluminescence Properties and Energy Transfer in a Novel Yellow Emitting Phosphor GdTaO4:Dy3+

2016 ◽  
Vol 16 (4) ◽  
pp. 3994-3997 ◽  
Author(s):  
Huijuan Zhang ◽  
Xinyu Tan ◽  
Yuhua Wang
Keyword(s):  
Energy Transfer ◽  
Vacuum Ultraviolet ◽  
Emission Spectra ◽  
Host Lattice ◽  
Excitation Spectra ◽  
Light Emitting ◽  
Ultraviolet Excitation ◽  
Plasma Display Panels ◽  
Chromaticity Coordinates ◽  
Plasma Display

The phosphor Dy3+ doped M type gadolinium orthotantalate GdTaO4 was prepared successfully by traditional solid state reaction and the photoluminescence of GdTaO4: xDy3+ (0.01 ≤ x ≤ 0.10) has been investigated under ultraviolet and vacuum ultraviolet excitation. In the excitation spectra of GdTaO4:Dy3+, the overlap appears between the host lattice excitation, the excitation lines of Gd3+ and the f–f transitions of Dy3+, which indicates that the energy transfer could occur from the host to the Dy3+ ions. In the emission spectra of the samples, the intense emissions of Dy3+ have been expectably revealed both upon excitation at 365 nm and 147 nm. And the chromaticity coordinates of GdTaO4: xDy3+ have been correspondingly calculated. The results indicate that GdTaO4:Dy3+ would be a novel yellow emitting phosphor applied in light emitting diodes (LEDs), plasma display panels (PDPs) and mercury-free fluorescent tubes.

Electrophosphorescent Light Emitting Devices Using New Iridium(III) Complexes

2001 ◽  
Vol 708 ◽  
Author(s):  
Rupasree Ragini Das ◽  
Chang-Lyoul Lee ◽  
Jang-Joo Kim
Keyword(s):  
Room Temperature ◽  
Emission Spectra ◽  
Bidentate Ligands ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Host Materials ◽  
Donor Acceptor ◽  
Phosphorescence At Room Temperature ◽  
Triplet Emitter

ABSTRACTWe have synthesized a new tris-orthometalated Ir(mpp)3 and several bis-orthometalated Ir(III) complexes of 3-methyl-2-phenylpyridine(Hmpp). The influence of the methyl substituent in Hmpp and different ligand environments on the optical, electrochemical and electroluminescence properties of the orthometalated complexes are examined by varying the donor acceptor properties. This includes several uninegative bidentate ligands consisting of different organic functional groups. Absorption, excitation and emission spectra in solution and solid state of these complexes agree with a strong electronic excitation to 1MLCT in Ir(mpp)3 and preferably to 3MLCT in other complexes. These complexes demonstrate strong phosphorescence at room temperature with a lifetime of 1-2 μs. Multilayer organic light emitting devices using these complexes as the triplet emitter are studied using PVK (poly(9-vinyl carbazole)), CBP (4,4'-N,N'-dicarbazole-biphenyl) and TAZ (3-phenyl-4-(1'-napthyl)-5-phenyl-1,2,4-triazole) as the host materials. Ir(mpp)3exhibits quite different behavior in different host materials.

New naphthyridine-based bipolar host materials for thermally activated delayed fluorescent organic light-emitting diodes

2019 ◽  
Vol 70 ◽  
pp. 55-62
Author(s):  
Tzu-Chin Yeh ◽  
Jhen-De Lee ◽  
Lu-Yu Chen ◽  
Tanmay Chatterjee ◽  
Wen-Yi Hung ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Host Materials

EVOLUTION OF LUMINESCENCE SPECTRA OF Ce3+-ION IN THE SOLID SOLUTIONS Ca1-xSrxS

2006 ◽  
Vol 20 (22) ◽  
pp. 1405-1416 ◽  
Author(s):  
O. KRACHNI ◽  
L. GUERBOUS ◽  
L. LOUAIL
Keyword(s):  
Band Gap ◽  
Lattice Constant ◽  
Solid Solutions ◽  
Local Structure ◽  
Emission Spectra ◽  
Host Lattice ◽  
Luminescence Properties ◽  
Luminescence Spectra ◽  
Additional Band

Luminescence spectra of Ce 3+-ion in Ca 1-x Sr x S solid solutions have been investigated. It has been shown that the evolution of Ce 3+ excitation and emission spectra through the concentration range may be interpreted in correlation with the variations, with the host lattice composition, of the lattice constant, the local structure in the activator neighborhood and the band gap. Under activator excitation, in addition to the two conventional bands, an additional band peaking at about 650 nm was observed (mainly in SrS ) and was related to the contamination of the samples as a consequence of extended storage. Except for this band, the luminescence properties did not change relatively to those obtained previously on the same samples. The most drastic modification affected SrS:Ce 3+, despite the fact that all the samples have been stored in the same conditions.

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