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Lorenzi R, Golubev NV, Ignat'eva ES, Sigaev VN, Ferrara C, Acciarri M, Vanacore GM, Paleari A. Defect-assisted photocatalytic activity of glass-embedded gallium oxide nanocrystals. J Colloid Interface Sci 2022; 608:2830-2838. [PMID: 34794807 DOI: 10.1016/j.jcis.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/22/2021] [Accepted: 11/02/2021] [Indexed: 10/19/2022]
Abstract
The use of glassceramics in photocatalysis is an attractive option for the realization of smart optical fibers and self-cleaning windows. Here we present the photocatalytic activity of germanosilicate glasses embedding Ga2O3 nanocrystals prepared by batch melting and glass heat treatment. The powdered material is used for UV-assisted degradation of rhodamine in water. The kinetics show changes after repeated experiments. In the first cycle, the apparent rate is governed by a second-order reaction with a Gaussian-like shape, whereas the second cycle follows a first-order reaction. The modification appears to be correlated with perturbations in the defect population. Photoluminescence has been used to monitor the evolution of such defects. Kinetic data on photoreactions and defect formation have been modelled in a combined frame in which the defect concentration determines the photocatalytic activity. The results prove the photocatalytic ability of the studied glassceramics. Moreover, the general validity of the kinetic model can be of interest for other systems in which the photocatalytic response depends on photoreactive species concentration.
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Affiliation(s)
- Roberto Lorenzi
- Department of Materials Science, University of Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy.
| | - Nikita V Golubev
- P.D. Sarkisov International Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125047 Moscow, Russia
| | - Elena S Ignat'eva
- P.D. Sarkisov International Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125047 Moscow, Russia
| | - Vladimir N Sigaev
- P.D. Sarkisov International Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125047 Moscow, Russia
| | - Chiara Ferrara
- Department of Materials Science, University of Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy
| | - Maurizio Acciarri
- Department of Materials Science, University of Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy
| | - Giovanni Maria Vanacore
- Department of Materials Science, University of Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy
| | - Alberto Paleari
- Department of Materials Science, University of Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy
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Lipatiev AS, Lotarev SV, Okhrimchuk AG, Lipateva TO, Fedotov SS, Sigaev VN. Crystal-in-glass architecture engineering: writing, erasing and rewriting by a femtosecond laser beam. CrystEngComm 2018. [DOI: 10.1039/c8ce00525g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Space-selectively erasing laser-written crystalline tracks by a femtosecond laser beam is demonstrated. It is possible to rewrite the oriented crystalline structure in re-melted glass and recover the crystal-in-glass architecture continuity.
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Affiliation(s)
- Alexey S. Lipatiev
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
| | - Sergey V. Lotarev
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
| | - Andrey G. Okhrimchuk
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
| | - Tatiana O. Lipateva
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
| | - Sergey S. Fedotov
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
| | - Vladimir N. Sigaev
- Mendeleev University of Chemical Technology of Russia
- Moscow 125480
- Russian Federation
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Paleari A, Golubev NV, Ignat'eva ES, Sigaev VN, Monguzzi A, Lorenzi R. Donor-Acceptor Control in Grown-in-Glass Gallium Oxide Nanocrystals by Crystallization-driven Heterovalent Doping. Chemphyschem 2017; 18:662-669. [PMID: 28067460 DOI: 10.1002/cphc.201601247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/04/2017] [Indexed: 11/07/2022]
Abstract
Incorporation of doping ions in nanocrystals is a strategy for providing nanophases with functions directly related to ion features. At the nanoscale, however, doping can also activate more complex effects mediated by perturbation of the nanophase size and structure. Here, we report a paradigmatic case in which we modify grown-in-glass γ-Ga2 O3 nanophases by nickel or titanium doping of the starting glass, so as to control the concentration of oxygen and gallium vacancies responsible for the light emission. Optical absorption and luminescence show that Ni2+ and Ti4+ ions enter into the nanophase, but differential scanning calorimetry and X-ray diffraction indicate that Ni and Ti also work as modifiers of nanocrystal growth. As a result, doping influences nanocrystal size and concentration, which in turn dictate the number of donors and acceptors per nanocrystal. Finally, the chain of effects turns out to control both the intensity and spectral distribution of the light emission.
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Affiliation(s)
- Alberto Paleari
- Department of Materials Science, University of Milano-Bicocca, via R. Cozzi 55, 20125, Milano, Italy.,P.D. Sarkisov Int. Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125190, Moscow, Russia
| | - Nikita V Golubev
- P.D. Sarkisov Int. Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125190, Moscow, Russia
| | - Elena S Ignat'eva
- P.D. Sarkisov Int. Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125190, Moscow, Russia
| | - Vladimir N Sigaev
- P.D. Sarkisov Int. Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125190, Moscow, Russia
| | - Angelo Monguzzi
- Department of Materials Science, University of Milano-Bicocca, via R. Cozzi 55, 20125, Milano, Italy
| | - Roberto Lorenzi
- Department of Materials Science, University of Milano-Bicocca, via R. Cozzi 55, 20125, Milano, Italy
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Golubev NV, Ignat'eva ES, Sigaev VN, Lauria A, De Trizio L, Azarbod A, Paleari A, Lorenzi R. Diffusion-driven and size-dependent phase changes of gallium oxide nanocrystals in a glassy host. Phys Chem Chem Phys 2015; 17:5141-50. [PMID: 25599651 DOI: 10.1039/c4cp05485g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phase transformations at the nanoscale represent a challenging field of research, mainly in the case of nanocrystals (NCs) in a solid host, with size-effects and interactions with the matrix. Here we report the study of the structural evolution of γ-Ga2O3 NCs in alkali-germanosilicate glass - a technologically relevant system for its light emission and UV-to-visible conversion - showing an evolution drastically different from the expected transformation of γ-Ga2O3 into β-Ga2O3. Differential scanning calorimetry registers an irreversible endothermic process at ∼1300 K, well above the exothermic peak of γ-Ga2O3 nano-crystallization (∼960 K) and below the melting temperature (∼1620 K). Transmission electron microscopy and X-ray diffraction data clarify that glass-embedded γ-Ga2O3 NCs transform into LiGa5O8via diffusion-driven kinetics of Li incorporation into NCs. At the endothermic peak, β-Ga2O3 forms from LiGa5O8 dissociation, following a nucleation-limited kinetics promoted by size-dependent order-disorder change between LiGa5O8 polymorphs. As a result of the changes, modifications of UV-excited NC light emission are registered, with potential interest for applications.
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Affiliation(s)
- N V Golubev
- P.D. Sarkisov International Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125047 Moscow, Russia
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Sigaev VN, Golubev NV, Ignat'eva ES, Paleari A, Lorenzi R. Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters. NANOSCALE 2014; 6:1763-1774. [PMID: 24352834 DOI: 10.1039/c3nr05210a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Wide-bandgap nanocrystals are an inexhaustible source of tuneable functions potentially addressing most of the demand for new light emitting systems. However, the implementation of nanocrystal properties in real devices is not straightforward if a robust and stable optical component is required as a final result. The achievement of efficient light emission from dense dispersions of Ga-oxide nanocrystals in UV-grade glass can be a breakthrough in this regard. Such a result would permit the fabrication of low cost UV-to-visible converters for monitoring UV-emitting events on a large-scale - from invisible hydrogen flames to corona dispersions. From this perspective, γ-Ga₂O₃ nanocrystals are developed by phase separation in Ga-alkali-germanosilicate glasses, obtaining optical materials based on a UV transparent matrix. Band-to-band UV-excitation of light emission from donor-acceptor pair (DAP) recombination is investigated for the first time in embedded γ-Ga₂O₃. The analysis of the decay kinetics gives unprecedented evidence that nanosized confinement of DAP recombination can force a nanophase to the efficient response of exactly balanced DAPs. The results, including a proof of concept of UV-to-visible viewer, definitely demonstrate the feasibility of workable glass-based fully inorganic nanostructured materials with emission properties borrowed from Ga₂O₃ single-crystals and tailored by the nanocrystal size.
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Affiliation(s)
- Vladimir N Sigaev
- P.D. Sarkisov International Laboratory of Glass-based Functional Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya Square 9, 125190 Moscow, Russia
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