Hackmanite—The Natural Glow-in-the-Dark Material

Agamah, Cecilia; Vuori, Sami; Colinet, Pauline; Norrbo, Isabella; Carvalho, José Miranda de; Nakamura, Liana Key Okada; Lindblom, Joachim; Goethem, L. Van; Emmermann, Axel; Saarinen, Timo; Laihinen, Tero; Laakkonen, Eero; Lindén, J.; Konu, Jari; Vrielinck, Henk; Heggen, David Van der; Smet, Philippe; Bahers, Tangui Le; Lastusaari, Mika

doi:10.1021/acs.chemmater.0c02554

Cited by 22 publications

(20 citation statements)

References 39 publications

(84 reference statements)

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“…On the other hand, low-dimensional materials, such as graphene, van der Waals crystals, MAX and MXenes, transition metal dichalcogenides, and ternary chalcogenides, − attract huge attention owing to their unique physical properties, including magnetic, and much efforts are being taken to discover new two-dimensional (2D) materials nowadays. Naturally occurring minerals like valleriite, which is composed of “noncommensurate” sulfide and hydroxide quasimonolayers with very diverse chemical, electronic and magnetic characters, may offer some clues as promising prototypes of the novel (nano)composite materials (see, for example, refs − ).…”

Section: Introductionmentioning

confidence: 99%

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

et al. 2021

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Valleriite is of interest as a mineral source of basic and precious metals and as an unusual material composed of two-dimensional (2D) Fe−Cu sulfide and magnesium hydroxide layers, whose characteristics are still very poorly understood. Here, the mineral samples of two types with about 50% of valleriites from Noril'sk ore provenance, Russia, were examined using Cu K-and Fe K-edge X-ray absorption fine structure (XAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), 57 Fe Mossbauer spectroscopy, and magnetic measurements. The Cu K X-ray absorption near-edge structures (XANES) spectra resemble those of chalcopyrite, however, with a higher electron density at Cu + centers and essentially differ from those of bornite Cu 5 FeS 4 ; the Fe K-edge was less informative because of accompanying oxidized Fecontaining phases. The post-edge XANES and extended XAFS (EXAFS) analysis reveal differences in the bond lengths, e.g., additional metal−metal distances in valleriites as compared with chalcopyrite. The XPS spectra confirmed the Cu + and Fe 3+ state in the sulfide sheets and suggest that they are in electron equilibrium with (Mg, Al) hydroxide layers. Mossbauer spectra measured at room temperature comprise central doublets of paramagnetic Fe 3+ , which decreased at 78 K and almost disappeared at 4.2 K, producing a series of hyperfine Zeeman sextets due to internal magnetic fields arising in valleriites. Magnetic measurements do not reveal antiferromagnetic transitions known for bornite. The specific structure and properties of valleriite are discussed in particular as a platform for composites of the 2D transition metal sulfide and hydroxide (mono)layers stacked by the electrical charges, promising for a variety of applications.

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Section: Introductionmentioning

confidence: 99%

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

et al. 2021

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“…A similar decrease was earlier reported for cathodoluminescence in hackmanites. [ 27 ] The emission was then assigned to oxygen vacancies occupied with one electron and thus the decrease of emission intensity was suggested to be due to the filling of the vacancies. [ 27 ] A similar explanation seems plausible also in the present case, because of the high number of thermalizing electrons available to fill oxygen vacancies.…”

Section: Resultsmentioning

confidence: 99%

“…The results show that with lower excitation energies, hackmanite shows its typical blue/white emission due to Ti 3+ ‐V O pairs. [ 3,5,27 ] When the excitation energy increases closer to the bandgap energy, the 400 nm band appears together with another band peaking at ≈320 nm. The highest excitation energies thus create UV range emission that we expect to be able to color the hackmanite.…”

Section: Resultsmentioning

confidence: 99%

Detection of X‐Ray Doses with Color‐Changing Hackmanites: Mechanism and Application

Vuori

Colinet

Norrbo

et al. 2021

Advanced Optical Materials

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Hackmanites, a variety of sodalite with the general formula Na8Al6Si6O24(Cl,S)2, are a family of nature‐based smart materials having the ability for reversible photochromism upon UV or X‐ray exposure. Being nontoxic, cheap, and durable, hackmanite would be an optimal material for the visual detection of the presence of X‐rays in simple portable systems. However, its X‐ray‐induced coloring abilities are so far known only qualitatively. In this work, a combination of experimental and computational methods is used to reveal the mechanism of X‐ray‐induced color changing in these materials. Finally, their use is demonstrated both in color intensity‐based X‐ray dosimetry and photochromic X‐ray imaging.

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“…Famous example are the zeolites and minerals derived from the sodalite structure. Hackmanite, a sulfide containing sodalite, is a material that exhibits persistent luminescence when doped with Ti ions [ 107 , 108 ]. The white emission has long durations and is the record-long for non-rare earth persistent phosphors [ 109 , 110 ].…”

Section: Inorganic Luminescent Materials Obtained By Microwave-assisted Methodsmentioning

confidence: 99%

Microwave-Assisted Preparation of Luminescent Inorganic Materials: A Fast Route to Light Conversion and Storage Phosphors

et al. 2021

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Luminescent inorganic materials are used in several technological applications such as light-emitting displays, white LEDs for illumination, bioimaging, and photodynamic therapy. Usually, inorganic phosphors (e.g., complex oxides, silicates) need high temperatures and, in some cases, specific atmospheres to be formed or to obtain a homogeneous composition. Low ionic diffusion and high melting points of the precursors lead to long processing times in these solid-state syntheses with a cost in energy consumption when conventional heating methods are applied. Microwave-assisted synthesis relies on selective, volumetric heating attributed to the electromagnetic radiation interaction with the matter. The microwave heating allows for rapid heating rates and small temperature gradients yielding homogeneous, well-formed materials swiftly. Luminescent inorganic materials can benefit significantly from the microwave-assisted synthesis for high homogeneity, diverse morphology, and rapid screening of different compositions. The rapid screening allows for fast material investigation, whereas the benefits of enhanced homogeneity include improvement in the optical properties such as quantum yields and storage capacity.

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Hackmanite—The Natural Glow-in-the-Dark Material

Cited by 22 publications

References 39 publications

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

Detection of X‐Ray Doses with Color‐Changing Hackmanites: Mechanism and Application

Microwave-Assisted Preparation of Luminescent Inorganic Materials: A Fast Route to Light Conversion and Storage Phosphors

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