Search

The demand for more efficient energy storage devices has led to the exponential growth of lithium-ion batteries. To overcome the limitations of these systems in terms of safety and to reduce environmental impact, solid-state technology emerges as a suitable approach. This work reports on a three-component solid polymer electrolyte system based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), the ionic liquid 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and clinoptilolite zeolite (CPT). The influences of the preparation method and of the dopants on the electrolyte stability, ionic conductivity, and battery performance were studied. The developed electrolytes show an improved room temperature ionic conductivity (1.9 × 10–4 S cm–1), thermal stability (up to 300 °C), and mechanical stability. The corresponding batteries exhibit an outstanding room temperature performance of 160.3 mAh g–1 at a C/15-rate, with a capacity retention of 76% after 50 cycles. These results represent a step forward in a promising technology aiming the widespread implementation of solid-state batteries., FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/CTM/50025/2021, UID/FIS/04650/2021, UID/EEA/04436/2021 and UID/QUI/0686/2021; and support from FEDER funds through the COMPETE 2020 Programme (projects PTDC/FISMAC/28157/2017 and POCI-01-0145-FEDER-007688). Grants SFRH/BD/140842/2018 (J.C.B.) and SFRH/BPD/121526/2016 (D.M.C) and contracts under the Stimulus of Scientific Employment, Individual Support CEECIND/00833/2017 (R.G.) and 2020.04028 CEECIND (C.M.C.) are acknowledged. Financial support from the Basque Government under the ELKARTEK program, Basque University System Research Groups, IT-1290-19 and the University of the Basque Country (GIU18/197). is also acknowledged

Materials science is increasingly relying on sustainable methods for synthesis of advanced materials. This work demonstrates the first template-free approach for the crystallization of tavorite, LiFePO4(OH), in the form of hollow microspheres and unique core (single crystal) –shell (aggregated particles) cross-like dendrites. The different morphologies have been obtained by hydrothermal synthesis. The kinetic pathways of crystallization reveal how the transformation of two different thermodynamically unstable phases, such as giniite (Fe5(PO4)4(OH)2∙2H2O) and Lithium sulfate (Li2SO4), leads to the same tavorite structure but with different morphologies based on the different mechanisms for crystal growth. Additionally, we provide standardized powder X-ray diffraction data and insights into the influence of the iron precursor on the crystal morphology of tavorite., S.F. thanks SEMAT at the University of Minho for the support. Work supported by the Portuguese Foundation for Science and Technology (FCT) under strategic funding UID/FIS/04650/2020 and UID/QUI/0686/2020, project PTDC/FIS-MAC/28157/2017, and contracts under the Stimulus of Scientific Employment, CEECIND/00833/2017 (R.G.) and 2020.04028 CEECIND (C.M.C.) as well POCH and European Union. Financial support from the Basque Government Industry Departments under the ELKARTEK, program is also acknowledged. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF and ESF) is gratefully acknowledged.

Metronidazole (MNZ) is a recalcitrant antibiotic with toxic and carcinogenic effects in aquatic environments. In this work, Fe-5(FO4)(4)(OH)(3)center dot 2H(2)O (giniite) particles were synthesised with three different alkaline cations (Li+, Na+ and K+) and used as Fenton catalysts for MNZ removal. It is shown that the addition of different cations during the hydrothermal synthesis process promote different morphologies from asterisk-like to flower-like and branches-like, maintaining the crystalline structure of pure giniite. The photo-Fenton activity of these particles was then evaluated through the degradation of MNZ under sunlight radiation for 9 h. The results indicate that the alkaline cation has a predominant role in the photo-Fenton efficiency, as demonstrated by the superior degradation efficiencies of Na@giniite particles (91.2% and 72.5% with giniite concentration of 0.2 g L-1 and 0.07 g L-1, respectively), related with its high surface area (10.7 m(2) g(-1)). Thus, it is demonstrated the suitability of Na@giniite particles as Fenton catalyst for MNZ removal from water. (C) 2020 Elsevier Ltd. All rights reserved., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020 and PEST-C/QUI/UIO686/2014 and under projects PTDC/BTM-MAT/28237/2017 and PTDC/FIS-MAC/28157/2017. We also thank the financial support from e FCT for grants SFRH/BD/122373/2016 (HS), SFRH/BPD/112547/2015 (CMC), IF/01516/2013 (SF), CTTI-70/19-CF(1) (P.M), and CEECIND/00833/2017 (RG). The authors thank funding by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively.

LiMn2O4 and LiMn1.5M0.5O4 (M: Ni, Cu, Co) doped particles have been synthetized by sol-gel. Particles between 50 and 200 nm were obtained with the cubic spinel structure of the LiMn2O4. Ni doping shows a more efficient substitution in the octahedral 16d site, replacing the Mn3+ thorn ion, improving the important drawback of poor cycling behavior of LiMn2O4. The average pore size decrease with the addition of the doped elements in the LiMn2O4 structure from 2.9 to 2.6 nm. Thermal analysis shows that the doped particles present higher thermal stability that the undoped ones. Electrochemical behavior of the cathodes prepared with each of the active materials show that the doping influenced the electrochemical performance of the active material. Thus, a specific capacity of 33, 74, 44 and 53 mAh g(-1) (at C) and 74, 89, 59 and 69 mAh g(-1) (at C/10) were obtained for LiMn2O4, LiMn1.5Ni0.5O4, LiMn1.5Cu0.5O4 and LiMn1.5Co0.5O4 cathodes, respectively. All cathodes present good electrochemical stability with low capacity fade of 0.5 and 3.1% for LiMn1.5Ni0.5O4 and LiMn1.5Cu0.5O4, respectively, after 50 cycles. These results show an improvement of electrochemical performance for LiMn2O4 doped with Ni, Cu and Co, demonstrating their suitability for lithium-ion battery systems., Work supported by the Portuguese Foundation for Science and Technology (FCT) funds strategic funding UID/FIS/04650/2020 and UID/QUI/0686/2020, project PTDC/FIS-MAC/28157/2017, and Grants CEECIND/00833/2017 (R.G.) and SFRH/BPD/112547/2015 (C.M.C.). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF and ESF) is gratefully acknowledged.

Two dicationic water soluble mixed triamine/diamine copper (II) complexes, of general formula [Cu(dien)NN]Br2(1–2) [dien = diethelenetriamine and NN is en = ethylenediamine or Me4en = N,N′,N,N′-tetramethylethylenediamine] were prepared under ultrasonic mode with a relatively high yield. These complexes were characterized by elemental microanalysis, UV visible IR spectroscopy, and thermal and electrochemical techniques. In addition, complex 2 structure was solved by X-ray single crystal and Hirshfeld surface analysis. The complex exhibits a distorted square pyramidal coordination environment around Cu(II) centre. The solvatochromism of the desired complexes was investigated in water and other suitable organic solvents. The results show that the Guttmann’s DN parameter values of the solvents have mainly contributed to the shift of the d–d absorption band towards the linear increase in the wavelength of the absorption maxima of the complexes. The complex 1 showed higher antibacterial activity against the studied microorganisms compared to complex 2. Both complexes revealed promising antibacterial activities., The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this Research group NO (RG-0257-1435-1436).

LiMn1.5Ni0.5O4 with spinel type of structure was synthesized by sol-gel method and doped by different rare-earth elements (Nd, Gd and Dy). It was found that the inclusion of rare-earth element preserves the cubic spinel structure, leads to smaller particle size and improves the cyclic performance of the produced batteries. The best battery performance was obtained after doping the spinel structure by Gd. Among the used rare-earth elements Gd is the only one with stable oxidation state of 3 + which leads to stabilization of the Mn dissolution.Thus, the improvements observed in battery performance (rate performance and cycle life) are due to the superior structural stability of the doped active materials. It is concluded that the LiMn1.48Ni0.5Gd0.02O4 sample is the one with the best overall performance to act as active material for cathodes in rechargeable lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and grants SFRH/BD/90313/2012 (A.G.), SFRH/BD/88397/2012 (R.G.) and SFRH/BPD/112547/2015 (C.M.C.). The authors are thankful for funding from the FCT under the Indo-Portuguese program of cooperation in science and technology (INT/Portugal/P-02/2013) 2014-2016. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged. The authors acknowledge the MRC, MNIT, Jaipur, Rajasthan, India for TEM, RAMAN characterization facilities for material characterization., info:eu-repo/semantics/publishedVersion

The synthetic analogue of the mineral giniite is a promising material for capture of phosphopeptides from complex tryptic digests, photocatalysis and cathode for lithium battery applications. In all these applications, the crystal morphology of giniite shows to be extremely important, however, the reported synthesis and crystal morphologies are scattered among a variety of approaches. Here we report a hydrothermal synthesis that allows achieving five different morphologies of giniite only by changing the pH by addition of three different alkaline cations (Na+, Li+ and K+) in form of hydroxides. At pH 2, micrometric sphere-like assemblies of nanoparticles were obtained. At pH 4, fractal dendritic crystals as well as intergrown flower-like and asterisk-like crystals were synthesized. At pH 6, the synthesis resulted in dagger-like crystals of dissolved dendritic structures., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. We thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and grants SFRH/BD/88397/2012 (R.G.), SFRH/BPD/112547/2015 (C.M.C.), and IF/01516/2013 (S.F.). S.L.M. thanks financial support from the Basque Government Industry Department under the ELKARTEK Program., info:eu-repo/semantics/publishedVersion

This work is devoted to study the photocatalytic ability of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites to degrade a dye molecule. Coatings were prepared by sol-gel method and calcined at different temperatures in a range of 400–750 °C. FTIR confirmed the existence of SiOTi bounds and the band located in the region between 570 and 600 cm−1 was used to calculate the framework Si/Al ratio of HY in the SiO2-TiO2-HY composites. XRD confirmed the presence of nanosized TiO2 (anatase phase) in all calcined composites. Nitrogen adsorption isotherms showed a decrease in surface area and pore volume for higher calcination temperature. A simple mechanical process was used to impregnate the different composites on the cotton substrates. The photocatalytic activity of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites was tested via the degradation of Rhodamine B (RhB) dye under similar solar irradiation. The best catalytic performance was achieved with the SiO2-TiO2 and SiO2-TiO2-HY composites subjected to a calcination treatment at 400 °C, whereas SiO2-TiO2 presented a decolourization and mineralization around 94% and 89%, respectively, after 2 h of irradiation. Furthermore, the products of RhB degradation were analysed and identified by using HPLC-ESI–MS and ion chromatography techniques and a photocatalytic mechanism was proposed., The authors thank CAPES from Brazil for the financial support of this work. This work is also a result of project “AIProcMat@N2020 − Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006 and the project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work also has been funded by ERDF through COMPETE2020 − Programa Operacional Competitividade e Internacionalização (POCI), Project POCI-01-0145-FEDER-006984 − Associate Laboratory LSRE-LCM and by national funds through FCT − Fundacão para a Ciência e a Tecnologia for project PTDC/AAGTEC/5269/2014 and Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016)., info:eu-repo/semantics/publishedVersion

LiMn2-xGdxO4 (x=0.00, 0.01 and x=0.04) spinel active material were prepared by sol-gel method. The morphology, crystal structure, thermal stability and electrochemical properties of the synthesized samples were evaluated. Gd-doping maintains the cubic spinel structure of LiMn2O4, leads to a decrease of the average particle size, and has a strong influence on the electrochemical properties of the cathodes. LiMn2-xGdxO4 cathode materials show two pairs of separated redox peaks, independently of the Gd-doping. After 40 charge-discharge cycles at C2, the discharge capacity was 55.9 mAh.g-1 and 33 mAh.g-1 for x=0.04 and x=0, respectively, corresponding to a capacity retention of 80% and 70%, respectively. The Gd-doped with x=0.04 showed improved cycling performance with respect to pristine LiMn2O4 due the smaller particle size and superior structural stability, showing its suitability for lithium-ion battery applications., The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013. A. G., C.M.C. and S. F. thank the FCT for grants SFRH/BD/90313/2012, SFRH/BPD/112547/2015 and IF/01516/2013, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology grant INT/Portugal/P-02/2013, 2014-2016. The authors are thankful for HRTEM and Raman characterization support from MRC, MNIT, Jairpur, INDIA. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. SLM thanks financial support from the Basque Government Industry Department under the ELKARTEK Program.

Molecular recognition at interfaces is essential approach for growth of crystals with selectively exposed facets. In general, this process is guided by impurities or solvents that favor the development of surfaces with particular reticular density. However, the specific agents that direct the crystal habit of one system often remain irrelevant for another, and thus, the control of crystal surface of many materials is still poorly known. Here we show selective resizing of prismatic crystal facets of germanium clinopyroxene (NaFeGe2O6) only by a simple switch between nitrate (Fe3+), chloride (Fe3+), and sulfate (Fe2+) sources of iron. The observed effect is explained by the combination of different rates of ion transport to the crystal surface and binding affinity of the hydrolyzed derivatives of the iron precursors that cap the crystal surface during the crystallization. Furthermore, this work reveals the first mild hydrothermal synthesis of germanium clinopyroxene, This work was supported by the Fundaçã̧o para a Ciência e a Tecnologia (FCT) − “Investigador 2013 (IF/01516/2013)”.

Silver has been recognized as a nontoxic, safe inorganic antibacterial/antifungal agent used for centuries. Silver demonstrates a very high potential in a wide range of biological applications, more particularly in the form of nanoparticles. Environmentally friendly synthesis methods are becoming more and more popular in chemistry and chemical technologies and the need for ecological methods of synthesis is increasing; the aim is to reduce polluting reaction by-products. Another important advantage of green synthesis methods lies in its cost-effectiveness and in the abundance of raw materials. During the last five years, many efforts were put into developing new greener and cheaper methods for the synthesis of nanoparticles. The cost decrease and less harmful synthesis methods have been the motivation in comparison to other synthesis techniques where harmful reductive organic species produce hazardous by-products. This environment-friendly aspect has now become a major social issue and is instrumental in combatting environmental pollution through reduction or elimination of hazardous materials. This review describes a brief overview of the research on green synthesis of silver metal nanoparticles and the influence of the method on their size and morphology.

Piezoelectric materials are interesting for the development of sensors and actuators for biomedical applications in areas such as smart prosthesis, implantable biosensors and biomechanical signal monitoring, among others. For acquiring or applying the electrical signal from/to the piezoelectric material, suitable electrodes can be produced from Ti based coatings with tailored multifunctional properties: conductivity and antibacterial characteristics through Ag inclusions. This work reports on Ti1−xAgx electrodes with different Ag/Ti atomic ratios deposited by dc and pulsed magnetron sputtering at room temperature on poly(vinylidene fluoride), PVDF. The X-ray diffraction (XRD) results revealed that the deposition conditions preserve the polymer structure and suggested the presence of crystalline Ti phase in pure titanium coating and fcc-Ag phase in pure silver coating. According to the results obtained from scanning electron microscopy (SEM) analysis, the coatings are homogeneous and no clusters were found; since -PVDF is anisotropic, the deposited coatings replicate the underlying substrate surface. Sheet resistivity values show a typical behavior of a binary alloy system, with low resistivity values for coatings of zone 1 (Ti rich) and zone 3 (Ag rich) and a slightly higher resistivity values in zone 2. The piezoelectricity of the different samples show similar values., The authors gratefully acknowledge the funding from the Portuguese National funds through the FCT – Fundação para a Ciência e a Tecnologia,(project SFRH/BD/71259/2010). Also thank support by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011 and the project Matepro – Optimizing Materials and Processes, ref. NORTE-07-0124-FEDER000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER)., info:eu-repo/semantics/publishedVersion

Made available in DSpace on 2017-12-07T19:55:01Z (GMT). No. of bitstreams: 2 license.txt: 2154 bytes, checksum: 4b0f01eb19f34a0ae8b22225f6f5120c (MD5) A microporous titanosilicate for selective killing of HeLa cancer cells_10.1039c3ra23381b.pdf: 1004087 bytes, checksum: 78e0a4ace665e6e511431ef58c2ab6af (MD5) Previous issue date: 2013

Microporous titanosilicates ETS-10, ETS-4 and GTS-1 were applied in the preparation of poly(vinylidene fluoride), PVDF, composites by solvent casting and melt crystallization. The spherulitic microstructure of neat PVDF is maintained but the crystallization phase is altered to the piezoelectric y-phase when the sample is melted at temperatures below 200ºC. The crystallinity and the temperature of polymer degradation are hardly influenced by the introduced titanosilicates, however ETS-4 incorporated in the polymer showed improved thermal stability. The dimensional characteristics of the porous framework, different confined mobility of the charge compensating cations and the interfacial polarization led to gradually increased dielectric constant that reached values of 18 at 1kHz. This behavior was accompanied by increased dielectric losses and a.c. conductivity. The reported PVDF/microporous titanosilicate composites represent a new class of materials with application potential for sensors and actuators., This work is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007, PTDC/CTM/69316/2006 and PTDC/CTM-NAN/112574/2009. ACL thanks the support of the FCT under grant SFRH/BD/62507/2009. The authors thank support from the COST Action MP1003 ‘European Scientific Network for Artificial Muscles’ (ESNAM). S. Ferdov thanks the support of the FCT project PTDC/CTM/108953/2008 and SEMAT at the UM.

Zeolites with framework types LTL, LTA, FAU and MFI were synthesized and used as fillers to prepare PVDF/zeolite composites. The obtained composites showed structural and electrical dependence on the pore system and chemical content of the inorganic host. The larger polymer-zeolite electrostatic interactions of the Y and A zeolites lead the polymer to crystallize in the electroactive -phase, which in the case of the L zeolite is prevented due to the reduced interaction area. The solvent and water encapsulation ability of the zeolite as well as improve of the dielectric response of the composite is directly related to the Si/Al ratio, leading zeolites with lower Si/Al ratios to larger dielectric responses and encapsulation efficiencies in the composites. These effects show also some dependency on the dimensionality of the pore system, the zeolite L containing 1D channels showing superior dielectric performance than the 3D pore system of zeolite Y., This work is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007, PTDC/CTM/69316/2006 and PTDC/CTM-NAN/112574/2009. ACL thanks the support of the FCT under grant SFRH/BD/62507/2009. The authors thank support from the COST Action MP1003 ‘European Scientific Network for Artificial Muscles’ (ESNAM). S. Ferdov thanks the support of the FCT project PTDC/CTM/108953/2008 and SEMAT at the UM.

In this work Nb-doped TiO2 thin films were deposited by d.c.-pulsed reactive magnetron sputtering at 500 °C from a composite target with weight fractions of 96% Ti and 4% Nb, using oxygen as reactive gas. In order to enhance the conductive properties, the as-deposited samples were treated in vacuum with atomic hydrogen at a substrate temperature of 500 °C. The atomic hydrogen flow was generated by a hot filament, inside a high-vacuum chemical vapour deposition reactor, at a temperature of 1750 °C. In order to optimise the hydrogen hot-wire treatments, the H2 pressure was varied between 1.3 and 67 Pa, the treatment time was monitored between 1 and 5 min and the hot-filament current was changed between 12 and 17 A. Dark conductivity was measured as a function of temperature and its value at room temperature was extrapolated and used to assess the effect of the hydrogen annealing on the charge transport properties. A two-order of magnitude increase in dark conductivity was typically observed for optimised hydrogen treatments (10 Pa), when varying the hydrogen pressure, resulting in a minimum resistivity of ~3×10−3 Ω cm at room temperature. The maximum amount of atomic H incorporation in oxygen vacancies was determined to be ~5.7 at.%. Carrier mobility and resistivity were also investigated using Hall effect measurements. Correlations between structural and electrical properties and the hydrogen treatment conditions are discussed. The purpose of these films is to provide a transparent and conductive front contact layer for a-Si based photovoltaics, with a refractive index that better matches that of single and tandem solar cell structures. This can be achieved by an appropriate incorporation of a very small amount of cationic doping (Nb5+) into the titanium dioxide lattice., Fundação para a Ciência e a Tecnologia (FCT)

Silicon nitride thin films for use as passivation layers in solar cells and organic electronics or as gate dielectrics in thin-film transistors were deposited by the Hot-wire chemical vapor deposition technique at a high deposition rate (1-3 Ǻ/s) and at low substrate temperature. Films were deposited using NH3/SiH4 flow rate ratios between 1 and 70 and substrate temperatures of 100º C and 250ºC. For NH3/SiH4 ratios between 40 and 70, highly transparent (T ~ 90%), dense films (2.56 - 2.74 g/cm3) with good dielectric properties and refractive index between 1.93 and 2.08 were deposited on glass substrates. Etch rates in BHF of 2.7 Ǻ/s and 10 MV cm−1., Fundação para a Ciência e Tecnologia (FCT) - FCT/CNRS programa com o contracto no. 20798, bolsa de investigaçao e projecto PTDC-CTM-66558-2006

Transparent, conducting, Al-doped ZnO films have been deposited, by dc and pulsed dc magnetron sputtering, on glass and electroactive polymer (poly(vinylidene fluoride)-PVDF) substrates. Samples have been prepared at room temperature varying the argon sputtering pressure, after optimizing other processing conditions. All ZnO:Al films are polycrystalline and preferentially oriented along the [002] axis. Electrical resistivity around 3.3 x 10(-3) Omega cm and optical transmittance of similar to 85% at 550 nm have been obtained for AZOY films deposited on glass, while a resistivity of 1.7 x 10(-2) Omega cm and transmittance of similar to 70% at 550 nm have been attained in similar coatings on PVDF. One of the main parameters affecting film resistivity seems to be the roughness of the substrate., The authors thank the Portuguese Foundation for Science and Technology - FCT: POCI/CTM/59425/2004 and PTDC/CTM/69362/2006, co-financed by European community fund FEDER.

The first examples of nanoparticles of pure layered Ln2(SiO4H)(OH)2(H2O)Cl (where Ln ) Eu, Gd, and Tb) and mixed microcrystalline layered lanthanide silicates containing different Eu/Gd and Tb/Gd ratios have been reported. The crystal structure of these silicates has been solved from synchrotron powder X-ray diffraction data. These materials display interesting and tuneable photoluminescence (PL) properties, such as energy transfer between different Ln3+ centers, illustrated here with the pairs Eu3+/Gd3+ and Tb3+/Gd3+. The PL properties of the mixed Eu3+/Gd3+ sample change upon F– for Cl- ion exchange, and this raises the possibility that this material may be exploited for sensing these ions. http://dx.doi.org/10.1021/cm702524n