Role of reactant concentration and identity of added cation in controlling emission from post-synthetically modified terbium incorporated zinc sulfide nanoparticles: an avenue for the detection of lead(<scp>ii</scp>) cations

Rudra, Saoni; Debnath, Gouranga H.; Mukherjee, Prasun

doi:10.1039/c8ra02403k

Cited by 17 publications

(42 citation statements)

References 40 publications

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“…The SAED pattern identifies characteristic signatures of (111), (200), (220), (311), (222), and (400) planes of cubic ZnS. These results are consistent with our previous reports. , …”

Section: Resultssupporting

confidence: 92%

Structural Evolution Controls Photoluminescence of Post-Synthetically Modified Doped Semiconductor Nanoparticles

2019

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This work discusses the photoluminescence properties of doped semiconductor nanoparticles by adding cadmium(II) nitrates post-synthetically to the terbium cation incorporated zinc sulfide [Zn(Tb)S] nanoparticles at room temperature to generate the Zn(Tb)S/Cd nanoparticles. The evolution of nanoparticle's emission is monitored as a function of amount of Cd 2+ , with [Zn(Tb)S]/[Cd 2+ ] = 1:10 −4 to 1:10, providing an opportunity to access materials of different chemical compositions. Structural features, as evaluated by X-ray diffraction and energy-dispersive X-ray spectroscopy, indicate a partial cation exchange of zinc by cadmium. No apparent replacement of terbium is noticed throughout the post-synthetic modification of the Zn(Tb)S nanoparticles until the relative reactant ratio reaches 1:10, and this only becomes noticeable with [Zn(Tb)S]/[Cd 2+ ] = 1:50. Remarkable differences in both broad and sharp emissions of nanoparticles and Tb 3+ , respectively, have been observed in the post-synthetic modification. The reaction initiates with a blue shift of nanoparticle's broad emission, and a further increase in Cd 2+ content results in a red shift. Tb 3+ emission, despite its insensitivity in the spectral band position due to the intra-configurational 4f transitions, shows a decrease in emission efficiency following post-synthetic modification. Formation of alloyed particles, however, significantly improved excitation contribution approaching the visible spectral region. Lifetime measurements of nanoparticles and Tb 3+ emission support the exchange of cations and the role of competitive nonradiative deactivation pathways, respectively. Collectively, nanoparticles with [Zn(Tb)S]/[Cd 2+ ] = 1:10 −4 to 1:10 −3 , 1:10 −2 , 1:10 −2 to 1:10, and 1:50 are argued to form Cd 2+ -induced surface trap-passivated Zn(Cd)(Tb)S, onset of Zn 1−x Cd x (Tb)S alloy formation, Zn 1−x Cd x (Tb)S alloys of varying compositions, and Zn 1−x Cd x S nanoparticles, respectively. Finally, this work provides a foundation to tune the properties of any emissive doped semiconductor nanoparticles in a lesser synthetically demanding fashion and has important implications in developing such materials.

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“…The SAED pattern identifies characteristic signatures of (111), (200), (220), (311), (222), and (400) planes of cubic ZnS. These results are consistent with our previous reports. , …”

Section: Resultssupporting

confidence: 92%

Structural Evolution Controls Photoluminescence of Post-Synthetically Modified Doped Semiconductor Nanoparticles

2019

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“…For postsynthetically modified II–VI NPs energy dispersive X-ray spectroscopy (EDS) showed (a) incorporation of Ln in the NPs, (b) significant changes in anion content of the NPs, and (c) an absence of complete cation exchange which is consistent with thermodynamic expectations . While Ln 3+ emission is appreciable in semiconductor NPs with a concentration in the range of tens of micromolar, the same can only be realized with a millimolar concentration for their free salts. ,, Dramatically altered excitation profiles upon monitoring Ln 3+ emissions in NPs, which overlap with NPs electronic absorption spectra, ,,− ,,− demonstrate the sensitization of the Ln 3+ emission by the NP. The significant lengthening of Ln 3+ emission lifetime in the NPs, as opposed to their corresponding free Ln 3+ salts in bulk solvent, , and the spectral changes of the NP capping ligand’s IR absorption spectrum by Ln 3+ ,, further substantiate the incorporation of the Ln 3+ in the NP lattice.…”

Section: Introductionsupporting

confidence: 57%

“…The Ln 3+ incorporation (in both synthetic and postsynthetic cases) has been demonstrated through observation of energy dispersive X-ray spectroscopic signatures for Ln 3+ in purified NPs, − and the increase in Ln 3+ photoluminescence in the NPs as compared to that found for free salts in bulk solvent. For postsynthetically modified II–VI NPs energy dispersive X-ray spectroscopy (EDS) showed (a) incorporation of Ln in the NPs, (b) significant changes in anion content of the NPs, and (c) an absence of complete cation exchange which is consistent with thermodynamic expectations .…”

Section: Introductionmentioning

confidence: 99%

“…During the past decade, research into the spectroscopy and materials chemistry of lanthanide luminescence has surged. With a propensity to exist primarily in a trivalent (+3) oxidation state, lanthanides (Ln 3+ ) comprise the f-block elements in the periodic table, ranging from lanthanum (La, atomic number 57) to lutetium (Lu, atomic number 71). By virtue of their 4f−4f transitions, Ln 3+ ions possess unusual photophysical properties and display sharp emission bands that span the ultraviolet (UV) (Gd 3+ ), entire visible (Pr 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ ), and near-infrared (NIR) (Nd 3+ , Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ ) spectral regions, in stark contrast to the broad emission bands of organic fluorophores (see Figure 1a).…”

Section: ■ Introductionmentioning

confidence: 99%

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Optimizing the Key Variables to Generate Host Sensitized Lanthanide Doped Semiconductor Nanoparticle Luminophores

Debnath

Mukherjee

2020

J. Phys. Chem. C

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Trivalent lanthanide (Ln3+) doped semiconductor nanoparticles (NPs) provide an avenue for developing unique luminophores, which combine the properties of Ln3+ and NPs. Realizing their promise requires a thorough understanding of their underlying photophysical processes. This article summarizes experimental findings and uses them to sketch a framework for understanding the important NP core and surface properties that affect Ln3+ luminescence. A charge trapping mediated Ln3+ emission sensitization mechanism is shown to operate in both the synthetically doped and postsynthetically modified NPs, and it is strongly affected by the energy offsets between the lanthanide and NP electronic states. While both the host (semiconductor NP) and guest (Ln3+) properties must be considered in designing and controlling the photophysical outcome, the predictable trends in Ln3+ energetics make it possible to predict trends and behaviors semiempirically. The role of spectral overlap mediated energy transfer mechanisms are shown to contribute negligibly to the sensitization. Proof of principle experiments to uncover the roles of surface localized dopants and surface capping ligands in governing the dopant emission, and the realization of emission from distinct Ln3+ in a codoped assembly, are discussed.

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“…Для синтеза простых и многослойных квантовых точек, как и для объемных кристаллических люминофоров, широко применяются полупроводники группы А(II)В(VI) [7][8][9][10][11][12]. На первый план выдвигаются соединения кадмия и цинка, в частности разрабатываются КТ состава Zn x Cd 1−x S и их легированные структуры [9,11].…”

Section: Introductionunclassified

Влияние Ионов Неодима (III) На Фотолюминесценцию Сульфидов Кадмия И Цинка В Полиакрилатной Матрице

Смагин¹,

Исаева²,

Шелепова³

2022

Физика И Техника Полупроводников

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Nanoscale particles ZnS:Nd3+, CdS:Nd3+ and (Zn,Cd)S:Nd3+ were synthesized and doped in a polymerizing methyl methacrylate medium during the production of optically transparent polyacrylate composites of the composition PMMA/ZnS:Nd3+, PMMA/CdS:Nd3+ and PMMA/(Zn,Cd)S:Nd3+. The excitation of photoluminescence (FL) and FL of semiconductor structures in composites is associated with the transition of electrons from the valence band to the conduction band and to the levels of structural defects of semiconductor particles, followed by recombination at these levels. Based on changes in the excitation spectra of FL and FL composites, assumptions are made about the structure of particles, the distribution of Nd3+ ions in it and their effect on photoluminescence.

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Role of reactant concentration and identity of added cation in controlling emission from post-synthetically modified terbium incorporated zinc sulfide nanoparticles: an avenue for the detection of lead(ii) cations

Cited by 17 publications

References 40 publications

Structural Evolution Controls Photoluminescence of Post-Synthetically Modified Doped Semiconductor Nanoparticles

Structural Evolution Controls Photoluminescence of Post-Synthetically Modified Doped Semiconductor Nanoparticles

Optimizing the Key Variables to Generate Host Sensitized Lanthanide Doped Semiconductor Nanoparticle Luminophores

Влияние Ионов Неодима (III) На Фотолюминесценцию Сульфидов Кадмия И Цинка В Полиакрилатной Матрице

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