Activator Systems in Zinc Sulfide Phosphors

Prener, J. S.; Williams, Ferd

doi:10.1149/1.2430325

Cited by 150 publications

(42 citation statements)

References 5 publications

(7 reference statements)

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“…The most recent theoretical study of systems of the KCl :T1 type shows, moreover, that there must be a considerable admixture of electron transfer states with the excited states of the TI ion, and that a model constructed solely from free activator ion states cannot provide an adequate description of phosphors of this type. The recent discovery of new absorption and emission bands in KCl :TI (Williams and Johnson 1959;Patterson, 1958) and studies on TI as an activator in other systems have further complicated the picture. It is clear that the very difficult, fundamental, and important task of computing quantitative configuration coordinate curves of simple KCI:Tltype phosphors in a theoretically rigorous manner has not been accomplished.…”

Section: Electrical Optical and Thermal Properties 289mentioning

confidence: 99%

“…With the more usual coactivators, such as the halogens and trivalent ions of the non-rare-earth type, the interaction of the activator and coactivator is not so readily seen; because in contrast to the line emission of rare-earth ions, which leads to easy detection of such interactions, these activators or coactivators yield rather broad emission bands. Nevertheless, small shifts in emission depending on the type of coactivator have been observed in certain cases, and this has been interpreted as evidence for the close spatial association of the two species of defect to form a composite activator center (Prener and Weil, 1959). "Association" has been proposed both in the above sense, where two differently charged defects agglomerate to form a complex activator center, and in at least two other senses.…”

Section: Luminescence With Charge Transportmentioning

confidence: 99%

“…"Association" has been proposed both in the above sense, where two differently charged defects agglomerate to form a complex activator center, and in at least two other senses. In one of these concepts of association, the spatial separation of the activator and coactivator species may be quite large; the "association" here involves the assumption that the luminescent transition is from an excited state of the coactivator to the ground state of the activator (Prener and Williams, 1956;. In still another context of association involving a spatially closer activator-coactivator pair, the luminescent transition is postulated to be from the ground state of the coactivator to the ground state of the acivator (Apple and Williams, 1959).…”

Section: Luminescence With Charge Transportmentioning

confidence: 99%

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Perspectives in Materials Research

Himmel¹,

Harwood²,

Harris³

et al. 1963

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Section: Electrical Optical and Thermal Properties 289mentioning

confidence: 99%

Section: Luminescence With Charge Transportmentioning

confidence: 99%

Section: Luminescence With Charge Transportmentioning

confidence: 99%

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Perspectives in Materials Research

Himmel¹,

Harwood²,

Harris³

et al. 1963

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“…6,7 The luminescence produced by recombination of an electron with a hole in the semiconductor has been attributed to a two-step reduction mechanism of peroxydisulfate (Fig. 1) …”

mentioning

confidence: 99%

“…1). [6][7][8] The initial step (Eq. 1) occurs by electron transfer from the conduction band (CB) to S 2 O 8 2-…”

mentioning

confidence: 99%

Electroluminescence at GaN and Ga[sub x]In[sub 1−x]N Electrodes in Aqueous Electrolytes

Hung

Halaoui

Bard

et al. 1999

Electrochem. Solid-State Lett.

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Electroluminescence (EL) of single crystal and thin films of GaN and Ga x In 1-x N (x = 0.8) was observed in aqueous solution containing peroxydisulfate on passage of cathodic currents. The resulting emission was compared with the photoluminescence of the same materials on ultraviolet light excitation. Only the subbandgap emission was observed in EL for GaN electrodes. The position and intensity of this emission peak depended on the applied potential, with a significant blue shift observed with increasing applied potential. The EL spectra of Ga x In 1-x N only showed a yellow luminescence band at lower applied potentials. When a more negative potential was applied, the near-bandedge emission (2.9 eV) appeared. © 1998 The Electrochemical Society. S1099-0062(98)03-062-4. All rights reserved.Manuscript submitted March 14, 1998; revised manuscript received June 17, 1998. Available electronically July 9, 1998.The III-V nitride semiconductors and their ternary compounds have recently attracted significant interest because of their potential use in optoelectronic devices, such as visible and ultraviolet (UV) light emitting diodes (LEDs) and lasers. It was mainly the realization of bright blue and green LEDs based on GaN heterostructures that spurred the increased efforts in making and understanding the properties of these materials. 1 InN, GaN, and AlN are direct bandgap semiconductors with bandgap energies of 1.9, 3.4, and 6.2 eV, respectively. The size of the bandgap can be manipulated, with energies ranging from the red region in the visible to the deep UV region, by varying the composition of the ternary materials. 2 While the optical characterization of these compounds by photoluminescence (PL) and solid-state electroluminescence (EL) has been extensively investigated, no reports of solution phase EL have appeared. Light can be generated at semiconductor electrodes through electron-hole recombination by the use of specific electrode reactions. The principles of this experiment are shown in Fig. 1. In this article, we report the EL properties of single crystal n-type GaN and Ga x In 1-x N thin films and bulk single crystal electrodes in the presence of peroxydisulfate. Experimental The GaN and Ga x In 1-x N (x = 0.8) thin film electrodes in this study were grown by low-pressure metallorganic chemical vapor deposition (MOCVD) on sapphire substrates. 3,4 The primary precursors employed were trimethylgallium (TMGa), trimethylindium (TMIn), ammonia (NH 3 ), and silane (SiH 4 ) for the n-type doping. The Si-doped GaN thin film was 1.5 µm thick and the Ga x In 1-x N thin film was 200 nm thick on a 1.5 µm thick GaN layer. Bulk single crystals of GaN were synthesized by heating NaN 3 and Ga metal in a stainless steel tube sealed under nitrogen atmosphere at 600-800°C for 24-96 h. 5 Larger single crystals, with dimensions > 0.1 mm, were prepared at 700-800°C with 3 mmole of NaN 3 . 5 GaN single crystal electrodes (0.6-0.7 mm) were used for this study. These electrodes were etched in 1 M KOH at 70°C for 25 s before a series ...

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Structures and Materials in Stretchable Electroluminescent Devices

Yin

Youssef

et al. 2021

Advanced Materials

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Stretchable electroluminescent (EL) devices are obtained by partitioning a large emission area into areas specifically for stretching and light‐emission (island–bridge structure). Buckled and textile structures are also shown effective to combine the conventional light emitting diode fabrication with elastic substrates for structure‐enabled stretchable EL devices. Meanwhile, intrinsically stretchable EL devices which are characterized with uniform stretchability down to microscopic scale are relatively less developed but promise simpler device structure and higher impact resistance. The challenges in fabricating intrinsically stretchable EL devices with high and robust performance are in many facets, including stretchable conductors, emissive materials, and compatible processes. For the stretchable transparent electrode, ionically conductive gel, conductive polymer coating, and conductor network in surface of elastomer are all proven useful. The stretchable EL materials are currently limited to conjugated polymers, conjugated polymers with surfactants and ionic conductors added to boost stretchability, and phosphor particles embedded in elastomer matrices. These emissive materials operate under different mechanisms, require different electrode materials and fabrication processes, and the corresponding EL devices face distinctive challenges. This review aims to provide a basic understanding of the materials meeting both the mechanical and electronic requirements and important techniques to fabricate the stretchable EL devices.

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Activator Systems in Zinc Sulfide Phosphors

Cited by 150 publications

References 5 publications

Perspectives in Materials Research

Perspectives in Materials Research

Electroluminescence at GaN and Ga[sub x]In[sub 1−x]N Electrodes in Aqueous Electrolytes

Structures and Materials in Stretchable Electroluminescent Devices

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