0000000001299525
AUTHOR
Enrico Bandiello
showing 48 related works from this author
Characterization of Flux-Grown SmxNd1–xVO4 Compounds and High-Pressure Behavior for x = 0.5
2019
The crystal structure and the vibrational and optical characteristics of flux-grown mixed lanthanide vanadate compounds SmxNd1–xVO4 (x = 0, 0.1, 0.25, 0.5, 0.75 and 1) are reported. A linear, monot...
Effect of High Pressure on the Crystal Structure and Vibrational Properties of Olivine-Type LiNiPO4
2018
In this work, we present an experimental and theoretical study of the effects of high pressure and high temperature on the structural properties of olivine-type LiNiPO4. This compound is part of an interesting class of materials primarily studied for their potential use as electrodes in lithium-ion batteries. We found that the original olivine structure (α-phase) is stable up to ∼40 GPa. Above this pressure, the onset of a new phase is observed, as put in evidence by the X-ray diffraction (XRD) experiments. The structural refinement shows that the new phase (known as β-phase) belongs to space group Cmcm. At room temperature, the two phases coexist at least up to 50 GPa. A complete conversio…
Precise Characterization of the Rich Structural Landscape Induced by Pressure in Multifunctional FeVO4
2020
We have studied the high-pressure behavior of FeVO4 by means of single-crystal X-ray diffraction (XRD) and density functional theory (DFT) calculations. We have found that the structural sequence o...
Phase behaviour of Ag2CrO4 under compression: Structural, vibrational, and optical properties
2013
We have performed an experimental study of the crystal structure, lattice dynamics, and optical properties of silver chromate (Ag2CrO4) at ambient temperature and high pressures. In particular, the crystal structure, Raman-active phonons, and electronic band gap have been accurately determined. When the initial orthorhombic Pnma Ag2CrO4 structure (phase I) is compressed up to 4.5 GPa, a previously undetected phase (phase II) has been observed with a 0.95% volume collapse. The structure of phase II can be indexed to a similar orthorhombic cell as phase I, and the transition can be considered to be an isostructural transition. This collapse is mainly due to the drastic contraction of the a ax…
Tuning the band gap of PbCrO4 through high-pressure: Evidence of wide-to-narrow semiconductor transitions
2014
The electronic transport properties and optical properties of lead(II) chromate (PbCrO4) have been studied at high pressure by means of resistivity, Hall-effect, and optical-absorption measurements. Band-structure first-principle calculations have been also performed. We found that the low-pressure phase is a direct band-gap semiconductor (Eg = 2.3 eV) that shows a high resistivity. At 3.5 GPa, associated to a structural phase transition, a band-gap collapse takes place, becoming Eg = 1.8 eV. At the same pressure the resistivity suddenly decreases due to an increase of the carrier concentration. In the HP phase, PbCrO4 behaves as an n-type semiconductor, with a donor level probably associat…
Aqueous electrolyte-gated ZnO transistors for environmental and biological sensing
2014
Electrolyte-gated transistors (EGTs) based on ZnO thin films, obtained by solution processing of suspensions of nanoparticles, have a low turn-on voltage (<0.5 V), a high on/off ratio and transconductance exceeding 0.2 mS. Importantly, the ZnO surface can be functionalized with a large variety of molecular recognition elements, making these devices ideal transducers in physiological and environmental monitoring. We present simple glucose-sensing and ion-selective EGTs, demonstrating the versatility of such devices in biosensing.
Lithium salt additives and the influence of their counterion on the performances of light-emitting electrochemical cells
2016
In this work we study the effect of the addition of lithium salts to light-emitting electrochemical cells (LECs), and in particular the effect of the lithium counterion. We found that the chosen lithium salts can substantially improve the device turn-on time as well as the overall lifetime, with respect to reference LECs using the pure emitter. A correlation between the lithium counterion and the corresponding device performance is established, and efficient LECs with lifetimes approaching 2000 hours are presented.
Pressure-induced chemical decomposition of copper orthovanadate (α-Cu3V2O8)
2021
The high pressure stability of α-Cu3V2O8 has been investigated via complementary high pressure synchrotron X-ray diffraction experiments and theoretical density functional theory calculations. The results of both experiment and theory are in close agreement. The main result of this work is that α-Cu3V2O8 undergoes a pressure-induced chemical decomposition into CuO and V2O5 at a modest pressure of ∼1.35 GPa according to the experimental observations, and at ∼2.45 GPa according to the calculations. The decomposition is investigated with enthalpy calculations and one of the main driving factors is the stability of the octhedral oxygen-coordination of the metal atoms in the decompositon product…
Operational Mechanism of Conjugated Polyelectrolytes
2014
Conjugated polyelectrolytes (CPEs) are versatile materials used in a range of organic optoelectronic applications. Because of their ionic/electronic nature, characterizing these materials is nontrivial, and their operational mechanism is not fully understood. In this work we use a methodology that combines constant-voltage-driven current-density transient measurements with fast current vs voltage scans to allow decoupling of ionic and electronic phenomena. This technique is applied to diodes prepared with cationic CPEs having different charge-compensating anions. Our results indicate that the operational mechanism of these devices is governed by electrochemical doping of the CPE. On the bas…
Ion-Selective Organic Electrochemical Transistors
2014
Ion-selective organic electrochemical transistors with sensitivity to potassium approaching 50 μA dec(-1) are demonstrated. The remarkable sensitivity arises from the use of high transconductance devices, where the conducting polymer is in direct contact with a reference gel electrolyte and integrated with an ion-selective membrane.
Pressure-Driven Symmetry-Preserving Phase Transitions in Co(IO3)2
2021
[EN] High-pressure synchrotron X-ray diffraction studies of cobalt iodate, Co(IO3)(2), reveal a counterintuitive pressure-induced expansion along certain crystallographic directions. High-pressure Raman and infrared spectroscopy, combined with density-functional theory calculations, reveal that with increasing pressure, it becomes energetically favorable for certain I-O bonds to increase in length over the full range of pressure studied up to 28 GPa. This phenomenon is driven by the high-pressure behavior of iodate ion lone electron pairs. Two pressure-induced isosymmetric monoclinic-monoclinic phase transitions are observed at around 3.0 and 9.0 GPa, which are characterized by increasing o…
PrVO$_4$ under High Pressure: Effects on Structural, Optical and Electrical Properties
2020
In pursue of a systematic characterization of rare-earth vanadates under compression, in this work we present a multifaceted study of the phase behavior of zircon-type orthovanadate PrVO$_4$ under high pressure conditions, up until 24 GPa. We have found that PrVO$_4$ undergoes a zircon to monazite transition at around 6 GPa, confirming previous results found by Raman experiments. A second transition takes place above 14 GPa, to a BaWO$_4$-I--type structure. The zircon to monazite structural sequence is an irreversible first-order transition, accompanied by a volume collapse of about 9.6%. Monazite phase is thus a metastable polymorph of PrVO$_4$. The monazite-BaWO$_4$-II transition is found…
Metal-Oxide-Free Methylammonium Lead Iodide Perovskite-Based Solar Cells: the Influence of Organic Charge Transport Layers
2014
Metal-oxide-free methylammonium lead iodide perovskite-based solar cells are prepared using a dual-source thermal evaporation method. This method leads to high quality reproducible films with large crystal domain sizes allowing for an in depth study of the effect of perovskite film thickness and the nature of the electron and hole blocking layers on the device performance. The power conversion efficiency increases from 4.7% for a device with only an organic electron blocking layer to almost 15% when an organic hole blocking layer is also employed. In addition to the in depth study on small area cells, larger area cells (approx. 1 cm(-2)) are prepared and exhibit efficiencies in excess of 10…
Controlling the mode of operation of organic transistors through side chain engineering
2016
Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode…
HgGa2 Se4 under high pressure: An optical absorption study
2015
High-pressure optical absorption measurements have been performed in defect chalcopyrite HgGa2Se4 to investigate the influence of pressure on the bandgap energy and its relation with the pressure-induced order–disorder processes that occur in this ordered-vacancy compound. Two different experiments have been carried out in which the sample undergoes either a partial or a total pressure-induced disorder process at 15.4 and 30.8 GPa, respectively. It has been found that the direct bandgap energies of the recovered samples at 1 GPa were around 0.15 and 0.23 eV smaller than that of the original sample, respectively, and that both recovered samples have different pressure coefficients of the dir…
Thermal equation of state of ruthenium characterized by resistively heated diamond anvil cell
2019
AbstractThe high-pressure and high-temperature structural and chemical stability of ruthenium has been investigated via synchrotron X-ray diffraction using a resistively heated diamond anvil cell. In the present experiment, ruthenium remains stable in the hcp phase up to 150 GPa and 960 K. The thermal equation of state has been determined based upon the data collected following four different isotherms. A quasi-hydrostatic equation of state at ambient temperature has also been characterized up to 150 GPa. The measured equation of state and structural parameters have been compared to the results of ab initio simulations performed with several exchange-correlation functionals. The agreement b…
Electronic properties and high-pressure behavior of wolframite-type CoWO4
2021
In this work we characterize wolframite-type CoWO4 under ambient conditions and under compression up to 10 GPa, with emphasis on its electronic structure. X-Ray diffraction and vibrational experiments, supported by ab initio calculations, show that CoWO4 is stable under high-pressure conditions, as no structural changes are detected in the studied pressure range. Interesting findings come from optical absorption spectroscopy. On the one hand, CoWO4 is confirmed to have one of the lowest band gaps among similar wolframites, around 2.25 eV. This makes CoWO4 suitable for use in applications such as the photocatalysis of organic pollutants and water splitting. Additionally, a monotonic decrease…
In situ characterization of the high pressure – high temperature melting curve of platinum
2019
AbstractIn this work, the melting line of platinum has been characterized both experimentally, using synchrotron X-ray diffraction in laser-heated diamond-anvil cells, and theoretically, using ab initio simulations. In the investigated pressure and temperature range (pressure between 10 GPa and 110 GPa and temperature between 300 K and 4800 K), only the face-centered cubic phase of platinum has been observed. The melting points obtained with the two techniques are in good agreement. Furthermore, the obtained results agree and considerably extend the melting line previously obtained in large-volume devices and in one laser-heated diamond-anvil cells experiment, in which the speckle method wa…
High-pressure phase transformations in NdVO4 under hydrostatic, conditions: a structural powder x-ray diffraction study
2019
Room temperature angle dispersive powder x-ray diffraction experiments on zircon-type NdVO4 were performed for the first time under quasi-hydrostatic conditions up to 24.5 GPa. The sample undergoes two phase transitions at 6.4 and 19.9 GPa. Our results show that the first transition is a zircon-to-scheelite-type phase transition, which has not been reported before, and contradicts previous non-hydrostatic experiments. In the second transition, NdVO4 transforms into a fergusonite-type structure, which is a monoclinic distortion of scheelite-type. The compressibility and axial anisotropy of the different polymorphs of NdVO4 are reported. A direct comparison of our results with former experime…
Temperature Effect of Ionic Transition Metal Complex Light-Emitting Electrochemical Cells
2013
ABSTRACTLight-Emitting Electrochemical Cells (LECs) consist of solution processable ionic light-emitting materials and use air stable electrodes. Their operational mechanism relies on both ionic and electronic conduction. The dynamic behavior is primarily determined by the ionic conductivity. Here, we demonstrate that with increasing temperature the LECs turn-on faster yet without decreasing the efficiency. This is due to the activation energy of ionic transport and the temperature independent photoluminescence quantum yields.
Effects of high-pressure on the structural, vibrational, and electronic properties of monazite-type PbCrO4
2012
We have performed an experimental study of the crystal structure, lattice dynamics, and optical properties of PbCrO 4 (the mineral crocoite) at ambient and high pressures. In particular, the crystal structure, Raman-active phonons, and electronic band gap have been accurately determined. X-ray-diffraction, Raman, and optical absorption experiments have allowed us also to completely characterize two pressure-induced structural phase transitions. The first transition is from a monoclinic structure to another monoclinic structure. It maintains the symmetry of the crystal but has important consequences in the physical properties; among others, a band-gap collapse is induced. The second one invo…
Phase Behavior of TmVO4 under Hydrostatic Compression: An Experimental and Theoretical Study
2020
We present a structural and optical characterization of magnetoelastic zircon-type TmVO4 at ambient pressure and under high pressure. The properties under high pressure have been determined experimentally under hydrostatic conditions and theoretically using density functional theory. By powder X-ray diffraction we show that TmVO4 undergoes a first-order irreversible phase transition to a scheelite structure above 6 GPa. We have also determined (from powder and single-crystal X-ray diffraction) the bulk moduli of both phases and found that their compressibilities are anisotropic. The band gap of TmVO4 is found to be Eg = 3.7(2) eV. Under compression the band gap opens linearly, until it unde…
Polymorphism of praseodymium orthovanadate under high pressure
2021
Zircon-type $\mathrm{PrV}{\mathrm{O}}_{4}$ has been studied at high pressures and room temperature by means of synchrotron powder x-ray diffraction. At room temperature, we observed the previously known zircon-to-monazite phase transition at 5.5(4) GPa and a second phase transition from monazite to a monoclinic structure at 12.7(8) GPa, which we identified as a $\mathrm{PbW}{\mathrm{O}}_{4}$-III-type phase. This conclusion is supported by our ab initio calculations, which also predict a scheelite-type phase to be stable at high pressure. Motivated by this finding, we subjected zircon-type $\mathrm{PrV}{\mathrm{O}}_{4}$ samples to high pressure (7 GPa) and temperature (600, 800, and 1000 \if…
Efficient vacuum deposited p-i-n and n-i-p perovskite solar cells employing doped charge transport layers
2016
Methylammonium lead halide perovskites have emerged as high performance photovoltaic materials. Most of these solar cells are prepared via solution-processing and record efficiencies (>20%) have been obtained employing perovskites with mixed halides and organic cations on (mesoscopic) metal oxides. Here, we demonstrate fully vacuum deposited planar perovskite solar cells by depositing methylammonium lead iodide in between intrinsic and doped organic charge transport molecules. Two configurations, one inverted with respect to the other, p-i-n and n-i-p, are prepared and optimized leading to planar solar cells without hysteresis and very high efficiencies, 16.5% and 20%, respectively. It is t…
Pressure-Induced Hexagonal to Monoclinic Phase Transition of Partially Hydrated CePO4
2019
We present a study of the pressure dependence of the structure of partially hydrated hexagonal CePO 4 up to 21 GPa using synchrotron powder X-ray diffraction. At a pressure of 10 GPa, a second-order structural phase transition is observed, associated with a novel polymorph. The previously unknown high-pressure phase has a monoclinic structure with a similar atomic arrangement as the low-pressure phase, but with reduced symmetry, belonging to space group C2. Group-subgroup relations hold for the space symmetry groups of both structures. There is no detectable volume discontinuity at the phase transition. Here we provide structural information on the new phase and determine the axial compress…
ChemInform Abstract: Tuning the Band Gap of PbCrO4Through High-Pressure: Evidence of Wide-to-Narrow Semiconductor Transitions.
2014
Commercial polycrystalline and cleaved platelets from natural PbCrO4 are studied in a diamond anvil cell at ≤ 21 GPa.
Influence of mobile ions on the electroluminescence characteristics of methylammonium lead iodide perovskite diodes
2016
In this work, we study the effect of voltage bias on the optoelectronic behavior of methylammonium lead iodide planar diodes. Upon biasing the diodes with a positive voltage, the turn-on voltage of the electroluminescence diminishes and its intensity substantially increases. This behavior is reminiscent of that observed in light-emitting electrochemical cells (LECs), single-layer electroluminescent devices in which the charge injection is assisted by the accumulation of ions at the electrode interface. Because of this mechanism, performances are largely independent from the work function of the electrodes. The similarities observed between planar perovskite diodes and LECs suggest that mobi…
Ionic-electronic interaction in optoelectronic and sensing devices
2016
En este trabajo se estudian las interacciones entre cargas electrónicas e iónicas y sus aplicaciones en sensores y dispositivos optoelectrónicos. El mecanismo de funcionamiento de los dispositivos optoelectrónicos actualmente más comunes, como los transistores de efecto de campo de capa fina (TFTs), los diodos emisores de luz (LEDs) y las células solares se basa solamente en procesos electrónicos, lo que significa que los efectos de cargas iónicas están ausentes, son irrelevantes o incluso perjudiciales para el propósito de dichos dispositivos. Sin embargo, muchas aplicaciones se benefician de la presencia de iones en la estructura de un dispositivo. Un ejemplo típico en el campo de investi…
CSD 1987965: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 2002439: Experimental Crystal Structure Determination
2020
Related Article: Enrico Bandiello, Catalin Popescu, Estelina Lora da Silva, Juan Ángel Sans, Daniel Errandonea, Marco Bettinelli|2020|Inorg.Chem.|59|18325|doi:10.1021/acs.inorgchem.0c02933
CSD 2004534: Experimental Crystal Structure Determination
2020
Related Article: Enrico Bandiello, Catalin Popescu, Estelina Lora da Silva, Juan Ángel Sans, Daniel Errandonea, Marco Bettinelli|2020|Inorg.Chem.|59|18325|doi:10.1021/acs.inorgchem.0c02933
CSD 1987954: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987963: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987960: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987956: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987958: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1979580: Experimental Crystal Structure Determination
2020
Related Article: Enrico Bandiello, Daniel Errandonea, Javier Gonz��lez-Platas, Pl��cida Rodr��guez-Hern��ndez, Alfonso Mu��oz, Marco Bettinelli, Catalin Popescu|2020|Inorg.Chem.|59|4882|doi:10.1021/acs.inorgchem.0c00147
CSD 1879403: Experimental Crystal Structure Determination
2019
Related Article: Enrico Bandiello, Daniel Errandonea, Sergio Ferrari, Julio Pellicer-Porres, Domingo Mart��nez-Garc��a, S. Nagabhusan Achary, Avesh K. Tyagi, Catalin Popescu|2019|Inorg.Chem.|58|4480|doi:10.1021/acs.inorgchem.8b03648
CSD 1987964: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987962: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987955: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1879404: Experimental Crystal Structure Determination
2019
Related Article: Enrico Bandiello, Daniel Errandonea, Sergio Ferrari, Julio Pellicer-Porres, Domingo Mart��nez-Garc��a, S. Nagabhusan Achary, Avesh K. Tyagi, Catalin Popescu|2019|Inorg.Chem.|58|4480|doi:10.1021/acs.inorgchem.8b03648
CSD 1987959: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 2002441: Experimental Crystal Structure Determination
2020
Related Article: Enrico Bandiello, Catalin Popescu, Estelina Lora da Silva, Juan Ángel Sans, Daniel Errandonea, Marco Bettinelli|2020|Inorg.Chem.|59|18325|doi:10.1021/acs.inorgchem.0c02933
CSD 1987961: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987957: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1987953: Experimental Crystal Structure Determination
2020
Related Article: Javier Gonzalez-Platas, Sinhue Lopez-Moreno, Enrico Bandiello, Marco Bettinelli, Daniel Errandonea|2020|Inorg.Chem.|59|6623|doi:10.1021/acs.inorgchem.0c00772
CSD 1979664: Experimental Crystal Structure Determination
2020
Related Article: Enrico Bandiello, Daniel Errandonea, Javier Gonz��lez-Platas, Pl��cida Rodr��guez-Hern��ndez, Alfonso Mu��oz, Marco Bettinelli, Catalin Popescu|2020|Inorg.Chem.|59|4882|doi:10.1021/acs.inorgchem.0c00147