Luminescent silver–lithium-zeolite phosphors for near-ultraviolet LED applications

Baekelant, Wouter; Aghakhani, Saleh; Fron, Eduard; Martín, Cristina; Woong-Kim, Cheol; Steele, Julian A.; Baerdemaeker, Trees De; d’Acapito, Francesco; Chernysov, Dmitry; Auweraer, Mark Van der; Lievens, Peter; Grandjean, D.; Roeffaers, Maarten B. J.; Hofkens, Johan; Coutiño-González, Eduardo

doi:10.1039/c9tc04674g

Cited by 19 publications

(28 citation statements)

References 41 publications

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“…[10][11][12][13][14][15] We have recently reported luminescence of silver clusters in calcined zeolites, with photoluminescence quantum efficiencies nearing 100 % when the interaction between the silver atoms and the host is optimised. 10 This makes zeolites particularly attractive hosts for the stabilization of luminescent silver clusters and other metals for applications in lighting, 16 as luminescent tags, 17 as humidity sensors, [18][19] and for biological imaging. [20][21][22] Zeolites are porous materials comprising a negatively-charged aluminosilicate framework balanced by extra-framework cations in the pores.…”

Section: Introductionmentioning

confidence: 99%

X‐Ray‐Induced Growth Dynamics of Luminescent Silver Clusters in Zeolites

Fenwick

Coutiño-González

Richard

et al. 2020

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In this work we used AlKα X-rays to drive the growth of luminescent silver clusters in zeolites.We tracked the growth of the silver species using Auger spectroscopy and fluorescence microscopy, by monitoring the evolution from their ions to luminescent clusters and then metallic, dark nanoparticles. We show that the growth rate in different zeolites is determined by the mobility of the silver ions in the framework and that the growth dynamics in calcined samples obeys the Hill-Langmuir equation for non-cooperative binding. Comparison of the optical properties of X-ray grown silver clusters with silver clusters formed by standard heat treatment indicates that the latter have a higher specificity towards the formation of luminescent clusters of a specific (small) nuclearity, whereas the former produces a wide distribution of cluster species as well as larger nanoparticles.

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Section: Introductionmentioning

confidence: 99%

X‐Ray‐Induced Growth Dynamics of Luminescent Silver Clusters in Zeolites

Fenwick

Coutiño-González

Richard

et al. 2020

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“…Baekelant and collaborators found that Li-exchanged LTA zeolites displayed PLQYs of about ≈10% in their fully hydrated state and ≈83% in the fully dehydrated state. [36] Moreover, the excitation wavelengths redshifted and broadened from below 300 to 340 nm, while the emission only slightly redshifted from 510 to 540 nm in highly luminescent dehydrated samples. The role of lithium co-cations in this optical modulation was unraveled through EXAFS analysis, showing that a stable Ag 4 (O) 2 -[Li + ] 6 m+ species was formed upon dehydration.…”

Section: Addition Of Counter-balancing Cations and Understanding Guest-host Interactionsmentioning

confidence: 93%

“…Its small dimension allows it to enter the sodalite cages of LTA zeolites and directly interact with silver nanoclusters differently from its larger counterparts, like sodium, potassium, or calcium cations, which do not permit wide optical tunability. [36]…”

Section: Addition Of Counter-balancing Cations and Understanding Guest-host Interactionsmentioning

confidence: 99%

“…The developed phosphors displayed a highly efficient green emission with PLQYs up to 83%, broad excitation range (between 300 and 400 nm), and high thermal stability (evidenced by spectral and thermogravimetric analysis); nevertheless, the observed emission was not broad enough to fulfill with ideal CCT and CRI values. [36] The quest for singlephase tunable silver-zeolite phosphors motivated the exploration of sensitizing agents and co-dopants, for example, the synergy between highly luminescent chalcogenide species (sulfur anions) and Ag-NCs entrapped into the cavities of sodalite zeolites (Figure 7a). Here, the white light emission's warmth and quality were controlled by the ratio of the coexisting emitting species indirectly regulated by the annealing temperature.…”

Section: Toward the Development Of Tunable Single-phase Silver-zeolite Phosphors For Lighting Devicesmentioning

confidence: 99%

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Tunable Luminescence from Stable Silver Nanoclusters Confined in Microporous Zeolites

Romolini

Steele

Hofkens

et al. 2021

Advanced Optical Materials

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properties associated with nanoclusters' molecule-like structure and energetics. Most notably, metal nanoclusters rose to research prominence in connection to the discovery of outstanding optoelectronic properties and have found practical application within catalysis, bioimaging, lighting and molecular sensing. [1][2][3][4][5][6] However, nanocluster' stabilization remains a significant impediment owing to their tendency to merge and form ever-larger aggregates at the loss of their interesting properties. Therefore, research efforts have been devoted to developing novel synthetic strategies to stabilize isolated metal nanoclusters; [7] popular approaches have often taken the form of using organic scaffolds such as DNA/RNA, proteins, and polymers. [8][9][10][11][12][13][14][15][16] The use of organic molecules gives rise to high synthesis yields, good luminescence performance, and strong compatibility with living organism, making them excellent candidates as fluorophores. Unfortunately, a main drawback is their poor long-term stability, especially in solid form, hindering their application, e.g., within lighting devices. On the other hand, template-mediated strategies based on the self-organization of the metal nanocluster within a confined volume (so-called "ship-in-a-bottle" approach) provide a promising alternative, one where the size and shape of the final metal nanocluster are dictated by the spatial restrictions imposed by the rigid host nanostructure. [17] To date, common templating structures have included glass matrices, [18] metal-organic frameworks, [19] and porous aluminosilicate zeolite crystals. [20] Here, we will shine light on zeolites as a promising scaffold for the assembly of highly luminescent and functional silver nanoclusters (Ag-NCs) within their (nano)porous interior (Figure 1a-c). As a host framework, zeolites possess molecular-sized channels and cages which enable them to confine molecules or metal (oxide) clusters inside their crystalline interior in a controlled fashion. Moreover, the framework is negatively charged, requiring counter-balancing extra-framework cations, which can be easily replaced through simple exchange methods. As shown in Figure 1d, forming the caged Ag-NCs involves a scalable bottom-up approach, whereby Ag + ions are made to self-assemble into nanoclusters via energy-driven activation (thermal treatment, photoactivation, or X-rays irradiation). Once the cluster is assembled, its optical response can be further tuned by the intentional exchange of additional guest

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“…By fine-tuning of the zeolite environment the researches achieved clusters with photoluminescence quantum yield approaching unity. Another Ag 4 cluster (dehydrated Ag 1 Li 11 -LTA zeolite) was found to feature a remarkable EQE of 83% with an emission maxima around 545 nm when excited between 300 and 400 nm [48]. The presence of Li + clearly changes the luminescence properties of this cluster in two ways: by shielding the interaction between cluster and zeolite oxygen framework and by contraction of Zeolites as Scaffolds for Metal Nanoclusters DOI: http://dx.doi.org/10.5772/intechopen.96876 the lattice parameter leading to a tightly confined cluster inside the sodalite cage of LTA zeolite.…”

Section: State Of the Artmentioning

confidence: 99%

Zeolites as Scaffolds for Metal Nanoclusters

Fron¹

2021

Advances in Geopolymer-Zeolite Composites - Synthesis and Characterization

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This chapter critically reviews the studies related to structural and photophysical properties of metal clusters within zeolites matrices and summarizes the progress made in understanding the host-guest interactions. The goal is to provide useful insight into the nature of such interactions and experiments used in identifying the excited state dynamics and the reaction mechanisms leading to the emitting species. Especially interesting are the combined experimental and computational approaches used to elucidate the structures and electronic transition of clusters inside the cavity. Although a number of excellent research articles have been published in the last years they only cover rather specific areas like organic photochemistry, confinement, charge transfer, theoretical modeling or photostimulated luminescence.

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Luminescent silver–lithium-zeolite phosphors for near-ultraviolet LED applications

Abstract: The applicability of Ag-exchanged zeolites as efficient phosphors for the development of near ultra-violet primary LEDs is described.

Cited by 19 publications

References 41 publications

X‐Ray‐Induced Growth Dynamics of Luminescent Silver Clusters in Zeolites

X‐Ray‐Induced Growth Dynamics of Luminescent Silver Clusters in Zeolites

Tunable Luminescence from Stable Silver Nanoclusters Confined in Microporous Zeolites

Zeolites as Scaffolds for Metal Nanoclusters

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