Molecular Orbital Theory

Marfunin, A. S.

doi:10.1007/978-3-642-67044-2_3

Cited by 7 publications

(7 citation statements)

References 14 publications

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“…Assuming that the Tb 3ϩ center exhibits octahedral coordination, 12 atomic orbital splitting can be applied to the 5d 1 4f 7 configuration. 16,17 According to this simple energy level splitting scheme, the excitation spectrum shows two strong peaks assigned to spinallowed transitions ( 7 D: 7 E and 7 T) and another two weak peaks assigned to spin-forbidden transitions ( 9 D: 9 E and 9 T). The energy difference between the peaks of the same spin could be regarded as crystal-field splitting.…”

Section: Resultsmentioning

confidence: 99%

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

Sohn

Choi

Park

2000

J. Electrochem. Soc.

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The photoluminescence behavior of Tb-activated green phosphors has been studied for the last few decades. 1-3 But most of the efforts have been focused only on yttrium aluminum garnet (YAG):Tb phosphors, 4-11 which have been investigated for their application for projection TV. 7,8 The present investigation aims at elucidating photoluminescence properties of YBO 3 :Tb phosphor based on the possibility that this phosphor could be applied for plasma TV. The YBO 3 :Tb phosphor has a strong absorption band in the vacuum ultraviolet (VUV) range, and its luminance under VUV excitation is as high as conventional commercial green phosphors. In this regard, the YBO 3 :Tb phosphor is favorable for plasma TV. Even though the color chromaticity and decay time of (Y 1Ϫx Tb x )BO 3 phosphor still needs some improvement, this phosphor could be a potential candidate for the green component of plasma TV. Tb 3ϩ has a relatively simple energy level structure: low-energy state, 7 F j ( j ϭ 6,...,0) and excited states 5 D 4 and 5 D 3 leading to luminescence. Concentration quenching and also cross relaxation are very well known phenomena in Tb-activated phosphors, which arise in common, independent of the adopted host material. There are a lot of investigations dealing with these behaviors in YAG:Tb phosphors. 9-11 We confirmed that YBO 3 :Tb phosphor exhibits similar behavior but there is a slight difference in detail. In order to investigate in detail such behavior, YBO 3 :Tb phosphors with a wide range of Tb 3ϩ concentration from 5 ϫ 10 Ϫ4 to 5 ϫ 10 Ϫ1 were examined using several experimental skills. The excitation spectra together with diffuse reflectance spectra were first measured in the range between 100 and 350 nm, and then the emission spectra were measured both under VUV and UV excitations for various Tb 3ϩ concentrations. Time-resolved emission spectra were also obtained to examine the cross relaxation in a systematic manner. The decay curves of 5 D 4 -7 Fj and 5 D 3 -7 F j transitions are examined, respectively, and then analyzed to get to a better understanding of the decay mechanism for each transition.Experimental The materials used in the present investigation with the general formula (Y 1Ϫx Tb x )BO 3 have been prepared through the solid-state reaction for x values between 5 ϫ 10 Ϫ4 and 5 ϫ 10 Ϫ1 . The raw materials used, Y 2 O 3 , B 2 O 3 , and Tb 4 O 7 , are completely blended with a certain amount of acetone, dried, and fired at the temperature of 1200ЊC in a neutral atmosphere (in N 2 ). The firing process was then followed by a reduction process at 900ЊC by introducing the gas mixture of nitrogen and a small amount of hydrogen (2%) into the furnace so that a higher emission intensity can be obtained. Such a reduction process enhances the emission intensity by about 20%. The reduced powders were pulverized and then examined using Xray diffraction in order to check whether or not a single phase was obtained. The results confirm that the vaterite-like structure (hexagonal structure) is detected. 12-14 All the powder...

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Section: Resultsmentioning

confidence: 99%

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

Sohn

Choi

Park

2000

J. Electrochem. Soc.

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“…As for the undistorted NbO 4 tetrahedra, the level scheme in the ground state is (1a 1 ) 2 (1t 2 ) 6 (1e) 4 (2t 2 ) 6 (1t 1 ) 6 , and the sequence of the excited orbitals is 2e < 3t 2 < 4t 2 < 2a 1 . 48 Herein, the filled orbitals are concentrated on the oxygen ions and the empty ones on the niobium ions. Thus, the lowest optical transition, t 1 → 2e, should be considered for the charge transfer from 2p(O) to 4d(Nb).…”

Section: Resultsmentioning

confidence: 99%

A highly efficient UV-to-red-light conversion by LuNbO₄:Eu³⁺ phosphors through exciton-assisted host-activator energy transfer

Xiong,

Liu,

Jiang

et al. 2023

J. Mater. Chem. C

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“…From the energies of the electronic transitions, it is possible to estimate the Racah parameters B and C and the ligand field splitting 10Dq as B = 729 cm À 1 , C = 3660 cm À 1 and 10Dq = 9430 cm À 1 respectively (a detailed description of the calculations is given in the Supporting Information). [74] The same approach was applied for some other selected compounds with Mn 2 + in halides with octahedrally coordinated sites with the results being compared in Table 1. It should be noted that this semi-empirical approach only offers estimate values for interelectronic repulsion and ligand field parame-…”

Section: Racah Parameters and Ligand Field Analysismentioning

confidence: 99%

Photoluminescence of Mn²⁺ in the Borosulfate Zn[B₂(SO₄)₄] : Mn²⁺—A Tool to Detect Weak Coordination Behavior of Ligands

Träger,

Pasqualini,

Huppertz

et al. 2023

Angew Chem Int Ed

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The impact of the surrounding ligand field is successfully exploited in the case of Eu2+ to tune the emission characteristics of inorganic photoactive materials with potential application in e.g., phosphor‐converted white light‐emitting diodes (pc‐wLEDs). However, the photoluminescence of Mn2+ related to intraconfigurational 3d5‐3d5 transitions is also strongly dependent on local ligand field effects and has been underestimated in this regard so far. In this work, we want to revive the idea how to electronically tune the emission color of a transition metal ion in inorganic hosts by unusual electronic effects in the metal‐ligand bond. The concept is explicitly demonstrated for the weakly coordinating layer‐like borosulfate ligand in the Mn(II)‐containing solid solutions Zn1‐xMnx[B2(SO4)4] (x = 0, 0.03, 0.04, 0.05, 0.10). Zn[B2(SO4)4]:Mn2+ shows orange narrow‐band luminescence at 590 nm, which is an unusually short wavelength for octahedrally coordinated Mn2+ and indicates an uncommonly weak ligand field. On the other hand, the analysis of the interelectronic Racah repulsion parameters reveals ionic Mn‐O bonds with values close to the Racah parameters of the free Mn2+ ion. Overall, this strategy demonstrates that electronic control of the metal‐ligand bond can be a tool to make Mn2+ a potent alternative emitter to Eu2+ for inorganic phosphors.

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Molecular Orbital Theory

Cited by 7 publications

References 14 publications

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

A highly efficient UV-to-red-light conversion by LuNbO₄:Eu³⁺ phosphors through exciton-assisted host-activator energy transfer

Photoluminescence of Mn²⁺ in the Borosulfate Zn[B₂(SO₄)₄] : Mn²⁺—A Tool to Detect Weak Coordination Behavior of Ligands

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Molecular Orbital Theory

Cited by 7 publications

References 14 publications

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

Photoluminescence Behavior of Tb[sup 3+]-Activated YBO[sub 3] Phosphors

A highly efficient UV-to-red-light conversion by LuNbO4:Eu3+ phosphors through exciton-assisted host-activator energy transfer

Photoluminescence of Mn2+ in the Borosulfate Zn[B2(SO4)4] : Mn2+—A Tool to Detect Weak Coordination Behavior of Ligands

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A highly efficient UV-to-red-light conversion by LuNbO₄:Eu³⁺ phosphors through exciton-assisted host-activator energy transfer

Photoluminescence of Mn²⁺ in the Borosulfate Zn[B₂(SO₄)₄] : Mn²⁺—A Tool to Detect Weak Coordination Behavior of Ligands