On Testing Entropic Inequalities for Superconducting Qudit

The aim of this work is to verify the new entropic and information inequalities for non-composite systems using experimental $5 \times 5$ density matrix of the qudit state, measured by the tomographic method in a multi-level superconducting circuit. These inequalities are well-known for bipartite and tripartite systems, but have never been tested for superconducting qudits. Entropic inequalities can also be used to evaluate the accuracy of experimental data and the value of mutual information, deduced from them, may charachterize correlations between different degrees of freedom in a noncomposite system.Comment: 5 pages, 6 figure

Analysis and comparison of three Coleoptera families in organic and conventional orchards within the Etna Regional Park (Catania, Sicily)

The objective of this work was to compare two agricultural management systems, organic and conventional, in the Etna Regional Park. The influence in both spatial and temporal dimensions, that natural habitats adjacent to these two different managed agricultural systems have on Coleoptera biocoenosis in orchards was also studied. This comparison was done through standardised data and multivariate analysis using a multi-taxa approach. Specifically, three families of the Order Coleoptera, namely Carabidae, Tenebrionidae and Staphylinidae (excluding Aleocharinae and Scydmaeninae) were studied.peer-reviewe

Structural properties of organometalic halide perovskite and their application in photodetectors

Hybrid organometallic halide perovskites have been intensively investigated in the past years as highly efficient light harvesters for various optoelectronic applications for both sensing and emitting light. However, many open questions remain regarding the crystallization process, environmental impact and implementation of the material into electrical circuits. The central theme of this PhD dissertation is the structural characterization of hybrid organicinorganic perovskites and device fabrication based on these materials. The focus is on methylammoniumlead iodide, CH3NH3PbI3 as one of the most efficient photovoltaic materials. External factors such as temperature, pressure, humidity, etc. affect the materials properties. Thus, it is crucial to study their influence for further applications. In this thesis, it will be shown, that under high pressure (20 GPa) inert gases as Ar and Ne form high-pressure-induced compounds with CH3NH3PbI3. For Ne pressure transmitting media such high-pressure transformation is reversible and the Ne-incorporated compoundis even stable at ambient conditions after decompression. We show that when applying repeated phase transitions during thermal cycling around both 330 and 160 K, CH3NH3PbI3 does not return to the initial state. Instead, at 330 K, the crystal stabilizes an incommensurately modulated tetragonal phase with successive transitions. On the other hand, performing thermal cycling around 160 K generates an increase in the concentration of domains of different phases. In addition, we studied the influence of thermal treatment on the crystal structure in the absence of any phase transition. For that reason, the lower dimensional compound of NH3CH2CH2NH3PbI4 was synthesized and characterized before and after annealing process. We observe and discuss a correlation between photoconductivity and increased disorder. In this work a novel approach of aerosol jet printing deposition of CH3NH3PbI3 has been developed. Making use of intermediate phases of the crystallization process, this deposition method enables the creation of 3D structures of organic-inorganic perovskites on various surfaces. This technique was successfully used in the fabrication of heterostructures based on CH3NH3PbI3 and graphene. Due to large trap-assisted photogain, these heterostructures are very promising for photoconductors. Taking into account the strong X-ray stopping power of the high atomic number Pb and I, devices based on CH3NH3PbI3/graphene heterostructures are excellent for X-ray detection. Such X-ray detectors demonstrate a record high sensitivity value of 2.2 x10^8 uC/(Gy cm^2)

Testing entropic inequalities for superconducting qudits

The aim of this work is to verify the new entropic and information inequalities for non-composite systems using experimental 5 imes 5 density matrix of the qudit state, measured by the tomographic method in a multi-level superconducting circuit. These inequalities are well-known for bipartite and tripartite systems, but have never been tested for superconducting qudits. Entropic inequalities can also be used to evaluate the accuracy of experimental data and the value of mutual information, deduced from them, may charachterize correlations between different degrees of freedom in a noncomposite system

Differential Response of the Photoluminescence and Photocurrent of Polycrystalline CH(3)NH(3)PbI(3 )and CH3NH3PbBr3 to the Exposure to Oxygen and Nitrogen

Because of their excellent photoelectric properties, organic-inorganic metal halide perovskites (MHPs), such as methylammonium lead triiodide, CH3NH3PbI3 (MAPbI(3)), and methylammonium lead tribromide, CH3NH3PbBr3 (MAPbBr(3)), are of great interest for the emerging MHPs-based photovoltaic technology. Despite extensive research efforts focused on physicochemical aspects of both MAPbI(3) and MAPbBr(3), the impact of environmental extremes, including various gaseous media, on their photo-electric properties remains poorly understood. In this context, here, the MHPs-based gas-sensing elements were grown by one-step solution process on the outer surface of cylindrical in shape quartz substrates with diameters varying in the range of 80-1100 mu m. The elongated cylinder-shaped geometry and high surface-to-volume ratios of the thus-prepared deposits revealed advantageous for designing miniature, light-transparent gas-flow chambers and made it possible to investigate the photoluminescence (PL) and photocurrent (PC) responses of both MHPs exposed to the precisely controlled recurrent flow of either O-2 or N-2. In addition, we could also collect the PL responses for the deposits of MAPbI(3 )and MAPbBr(3), positioned side-by-side close to each other and therefore simultaneously exposed to identical environmental conditions. Specifically, we found that under exposure to O-2 the PL responses of MAPbI(3) and MAPbBr(3 )were markedly opposite; i.e., the PL decreased for MAPbI(3), whereas it increased for MAPbBr(3). In contrast, under the exposure to N-2, the PL of MAPbI(3 )increased, while it decreased for MAPbBr(3). A considerably differential behavior was also found for the PC responses. In particular, under recurrent exposures to both gaseous media, the PL and PC responses of MAPbBr(3) correlated, whereas for MAPbI(3) they anticorrelated. In conclusion, the distinctly opposite PL and PC responses of polycrystalline deposits of MAPbI(3) and MAPbBr(3 )to O-2 and N-2 reported herein point to markedly contrasting properties of the surface carrier traps and defects for these two MHPs. This study also evidences that a side-by-side arrangement of elongated cylindrically shaped substrates coated with two different MHPs, due to their differential responses to exposure to O-2 or N-2, can function as a simple differential gas detector

Effect of Thermal Cycling on the Structural Evolution of Methylammonium Lead Iodide Monitored around the Phase Transition Temperatures

Optoelectronic devices and solar cells based on organometallic hybrid perovskites have to operate over a broad temperature range, which may contain their structural phase transitions. For instance, the temperature of 330 K, associated with the tetragonal-cubic transformation, may be crossed every day during the operation of solar cells. Therefore, the analysis of thermal cycling effects on structural and electronic properties is of significant importance. This issue is addressed in the case of methylammonium lead iodide (CH3NH3PbI3) across both structural phase transitions (at 160 and 330 K). In situ synchrotron radiation X-ray diffraction (XRD) data recorded between 140 and 180 K show the emergence of a boundary phase between the orthorhombic and tetragonal phases, which becomes more abundant with successive thermal cycles. At high temperatures, around 330 K, an incommensurately modulated tetragonal phase is formed upon repeated crossings of the phase boundary between tetragonal and cubic phases. These alterations, which indicate a gradual evolution of the material under operating conditions of photovoltaic devices, are further documented by electrical resistivity and heat capacity measurements

Pressure-induced transformation of CH3NH3PbI3: the role of the noble-gas pressure transmitting media

The photovoltaic perovskite, methylammonium lead triiodide [CH3NH3PbI3 (MAPbI(3))], is one of the most efficient materials for solar energy conversion. Various kinds of chemical and physical modifications have been applied to MAPbI(3) towards better understanding of the relation between composition, structure, electronic properties and energy conversion efficiency of this material. Pressure is a particularly useful tool, as it can substantially reduce the interatomic spacing in this relatively soft material and cause significant modifications to the electronic structure. Application of high pressure induces changes in the crystal symmetry up to a threshold level above which it leads to amorphization. Here, a detailed structural study of MAPbI(3) at high hydrostatic pressures using Ne and Ar as pressure transmitting media is reported. Single crystal X-ray diffraction experiments with synchrotron radiation at room temperature in the 0-20 GPa pressure range show that atoms of both gaseous media, Ne and Ar, are gradually incorporated into MAPbI(3), thus leading to marked structural changes of the material. Specifically, Ne stabilizes the high-pressure phase of Ne(x)MAPbI(3) and prevents amorphization up to 20 GPa. After releasing the pressure, the crystal has the composition of Ne(0.97)MAPbI(3), which remains stable under ambient conditions. In contrast, above 2.4 GPa, Ar accelerates an irreversible amorphization. The distinct impacts of Ne and Ar are attributed to differences in their chemical reactivity under pressure inside the restricted space between the PbI6 octahedra

Light-induced charge transfer at the CH3NH3PbI3/TiO2 interface-a low-temperature photo-electron paramagnetic resonance assay

The performance of organic-inorganic metal halide perovskites-based (MHPs) photovoltaic devices critically depends on the design and material properties of the interface between the light-harvesting MHP layer and the electron transport layer (ETL). Therefore, the detailed insight into the transfer mechanisms of photogenerated carriers at the ETL/MHP interface is of utmost importance. Owing to its high charge mobilities and well-matched band structure with MHPs, titanium dioxide (TiO2) has emerged as the most widely used ETL material in MHPs-based photovoltaic devices. Here, we report a contactless method to directly track the photo-carriers at the ETL/MHP interface using the technique of low-temperature electron paramagnetic resonance (EPR) in combination with in situ illuminations (Photo-EPR). Specifically, we focus on a model nanohybrid material consisting of TiO2-based nanowires (TiO(2)NWs) dispersed in the polycrystalline methylammonium lead triiodide (MAPbI(3)) matrix. Our approach is based on observation of the light-induced decrease in intensity of the EPR signal of paramagnetic Ti3+ (S=1/2) in non-stoichiometric TiO(2)NWs. We associate the diminishment of the EPR signal with the photo-excited electrons that cross the ETL/MHP interface and contribute to the conversion of Ti3+ states to EPR-silent Ti2+ states. Overall, we infer that the technique of low-temperature Photo-EPR is an effective strategy to study the transfer mechanisms of photogenerated carriers at the ETL/MHP interface in MAPbI(3)-based photovoltaic and photoelectronic systems