Enhanced Dopant Solubility and Visible-Light Absorption in Cr–N Codoped TiO<sub>2</sub> Nanoclusters

Chiodi, Mirco; Cheney, C. Parks; Vilmercati, Paolo; Cavaliere, Emanuele; Mannella, Norman; Weitering, Hanno H.; Gavioli, Luca

doi:10.1021/jp208834n

Cited by 72 publications

(58 citation statements)

References 60 publications

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“…In this respect, the synthesis and the growth of controlled antimicrobial coating with bi-NPs in a single step are an open challenge. A feasible alternative to directly synthesize and deposit controlled nano-structured multielemental coatings is based on gas-phase synthesis techniques, [21][22][23] and in particular Supersonic Cluster Beam Deposition (SCBD). 22,23 Here, the synthesized NPs form a beam that allows the direct deposition of the coating on the substrate.…”

confidence: 99%

“…Moreover, our data clearly indicate that the compositional changes in the pristine rod (i.e., pure Ag, AgTi8020, AgTi5050) correspond to an analogous variation in the produced bi-NPs stoichiometry, proving that SCBD is a powerful tool to tailor the NPs chemical composition simply adjusting the Ag/Ti relative concentration in the initial rod. It is also worth noting that this method has already been used to deposit Np coatings on glass, 24 sapphire, 7 semiconductors, 23 and on PVA electrospun fibers, 32 and can be extended to any metal surface, even textiles and paper, provided they can be inserted into vacuum. Such flexibility can open a wide range of applications of such coatings, from sensors to paper electronics.…”

Section: -532xmentioning

confidence: 99%

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Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

et al. 2017

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Ultrathin coatings based on bi-elemental nanoparticles (NPs) are very promising to limit the surface-related spread of bacterial pathogens, particularly in nosocomial environments. However, tailoring the synthesis, composition, adhesion to substrate, and antimicrobial spectrum of the coating is an open challenge. Herein, we report on a radically new nanostructured coating, obtained by a one-step gas-phase deposition technique, and composed of bi-elemental Janus type Ag/Ti NPs. The NPs are characterized by a cluster-in-cluster mixing phase with metallic Ag nano-crystals embedded in amorphous TiO2 and present a promising antimicrobial activity including also multidrug resistant strains. We demonstrate the flexibility of the method to tune the embedded Ag nano-crystals dimension, the total relative composition of the coating, and the substrate type, opening the possibility of tailoring the dimension, composition, antimicrobial spectrum, and other physical/chemical properties of such multi-elemental systems. This work is expected to significantly spread the range of applications of NPs coatings, not only as an effective tool in the prevention of healthcare-associated infections but also in other technologically relevant fields like sensors or nano-/micro joining

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confidence: 99%

Section: -532xmentioning

confidence: 99%

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

et al. 2017

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“…In particular, the formation energy of Eu can be lowered by 0.02-0.30 eV when codoped with cation donors, and can be lowered by 0.78-0.95 eV when codoped with anion donors. This is attributed to the charge transfer from the donor's p states to acceptor's (Eu) f states combined with a strain effect [62], which stabilize the electronic structure of the doped system and in turn improves the impurity solubility, and this can be further evidenced by analogical experiments [63][64][65]. Note that the formation energy of Eu generally can be lowered more when codoped with anion donors.…”

Section: The Magnetic Codopingmentioning

confidence: 99%

Realization of stable ferromagnetic order in a topological insulator: Codoping-enhanced magnetism in4ftransition metal dopedBi2Se<

Deng¹,

Zhang²,

Zhang³

et al. 2016

Phys. Rev. B

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The quantum anomalous Hall effect (QAHE), originates form a combination of the spin-orbital coupling and the breaking of time-reversal symmetry due to intrinsic ferromagnetic ordering, was recently observed in Cr-and V-doped magnetic topological insulators (TI). However, it was only observed at extremely low temperatures due to the low ferromagnetic Curie temperature and tiny magnetically-induced gap. To fully understand the mechanism of the ferromagnetic ordering whereby improving the ferromagnetism, we investigated 4f transition-metal-doped Bi 2 Se 3 , using density-functional-theory approaches. We predict that Eu and Sm can introduce stable long-range ferromagnetic states in Bi 2 Se 3 , with large magnetic moments and low impurity disorders .Additionally, codoping is proposed to tune the Fermi level into the gap, which simultaneously improve the magnetic moment and the incorporation of magnetic ions. Our findings thus offer a critical step in facilitating the realization of QAHE in TI systems.PACS numbers: 71.20.Nr, 61.72.U-, 75.50.Pp I. INTRODUCTIONThe Quantum Hall effect (QHE), characterized by the quantized Hall conductance, with the formation of Laudau levels under an external magnetic field, was observed in two-dimensional electron systems more than 30 years ago[1,2]. As first proposed by Haldane[3], by circulating currents loop on a honeycomb lattice, the QHE can exist even without the external magnetic field and the formation of Laudau levels, namely the Quantum anomalous Hall effect (QAHE). However, the Haldane model is difficult to realize experimentally. Later, numerous models were proposed to realize QAHE in realistic materials, including magnetically doped quantum wells [4][5][6][7], transition metal oxide heterostructures [8][9][10][11][12][13], grapheme /silicene [14][15][16][17][18][19], magnetic topological insulator (TI) thin films [20-26], etc. [27-29]. However, the QAHE was only reported to be successful in Cr-and V-doped (Bi,Sb) 2 Te 3 magnetic TI thin films [30][31][32][33][34][35][36].The key idea for the realization of QAHE is to introduce the time-reversal symmetry (TRS) breaking perturbations, e.g. a ferromagnetic order in topological insulators, usually by doping the TI with magnetic impurities [30][31][32][33][34][35][36]. The introduced exchange splitting can destroy the band inversion in one of the spin channels, whilst keeping the nontrivial band topology in the other spin channel due to the spin-orbital coupling, which opens up a finite gap at the Dirac point and lead to the QAHE [37]. The reason for chose the TI system, especially the Bi 2 Se 3 family which has been proved successful in QAHE, is that besides its strong SOC and a single-surface Dirac cone, the ferromagnetic orders can be derived directly from the large Van Vleck spin susceptibility in the host without the mediation of itinerant carriers [24], which eventually makes the QAHE being possible. However, the QAHE observed from recent experimental observations typically occurs at extremely low temperatures because of t...

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“…Due to its large band gap, TiO 2 absorbs less than 5 % of the available solar photons. There has been tremendous interest in recent years to improve visible light absorption of TiO 2 , including dye sensitization for photoexcitation of TiO 2 in the visible spectral region via photoinduced interfacial electron transfer [11][12][13], and doping with light and heavy elements to promote less M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 energetic excitations of electrons from mid-gap dopant levels to conduction band of TiO 2 [14][15][16]. Another emerging approach involves a charge transfer from surface modifier into the conduction band of nanocrystalline TiO 2 particles.…”

Section: Introductionmentioning

confidence: 99%

Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives

Milićević

Đorđević

Lončarević

et al. 2015

Microporous and Mesoporous Materials

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TiO 2 powders with different specific surface area were prepared using reproducible, sol-gel synthetic route and their ability to form hybrids with catechol and 5-amino salicylic acid was compared with the commercially available Degussa P25 TiO 2 powder. Microstructural characterization involving transmission electron microscopy, X-ray diffraction analysis and nitrogen adsorption-desorption isotherms indicated that TiO 2 samples cover reasonably wide size and/or specific surface area range (50-115 m 2 /g). The surface modification of TiO 2 powders with catechol and 5-amino salicylic acid induced significant shift of absorption to the visible spectral region due to charge transfer complex formation. It should be emphasized that tunable optical properties of TiO 2 in powder form have never been reported in the literature. The largest red M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 shift of the absorption onset was observed for sample with the largest specific surface area upon surface modification with both ligands. The binding of the modifier molecules to the surface Ti atoms was studied using Fourier transform infrared spectroscopy.

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Enhanced Dopant Solubility and Visible-Light Absorption in Cr–N Codoped TiO₂ Nanoclusters

Cited by 72 publications

References 60 publications

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

Realization of stable ferromagnetic order in a topological insulator: Codoping-enhanced magnetism in4ftransition metal dopedBi2Se<

Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives

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Enhanced Dopant Solubility and Visible-Light Absorption in Cr–N Codoped TiO2 Nanoclusters

Cited by 72 publications

References 60 publications

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

Realization of stable ferromagnetic order in a topological insulator: Codoping-enhanced magnetism in4ftransition metal dopedBi2Se<

Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives

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Enhanced Dopant Solubility and Visible-Light Absorption in Cr–N Codoped TiO₂ Nanoclusters