Search results for "Dye"
showing 10 items of 577 documents
Effects of Different Test Setups on the Experimental Tensile Behaviour of Basalt Fibre Bidirectional Grids for FRCM Composites
2020
Fibre-reinforced cementitious matrix (FRCM) composites have been effectively used during the last ten years for the strengthening of existing concrete and masonry structures. These composite materials are made of medium- and high-strength fibre meshes embedded in inorganic matrices. Synthetic fibres are the ones that are currently the most used
Improvement of DSSC performance by voltage stress application
2016
Dye-sensitized solar cells (DSSCs) are promising third generation photovoltaic devices given their potential low cost and high efficiency. Some factors still affect DSSCs performance, such structure of electrodes, electrolyte compositions, nature of the sensitizers, power conversion efficiency, long-term stability, etc. In this work we discuss the effect of electrical stresses, which allow to improve DSSC performance. We have investigated the outcomes of forward and reverse DC bias stress as a function of time, voltage, and illumination level in the DSSCs sensitized with the N719, Ruthenium complex based dye. We demonstrate that all the major solar cell parameters, i.e., open circuit voltag…
Laser Beam Induced Current measurements on Dye Sensitized Solar Cells and thin film CIG(S,SE)<inf>2</inf> modules
2017
Calculating the efficiency of a solar cell depends on a precise knowledge of its area. Indeed, the photoresponse uniformity is essential to improve the manufacturing process. In this work we report on Laser Beam Induced Current measurements performed on CIG(S,Se) 2 modules and Dye Sensitized Solar Cells. These measurements, performed via a green and a red HeNe lasers both operating at an optical irradiance of 1 Sun, allowed to obtain an accurate photoresponse map of the specimens and highlighted the non-uniformities with a spatial resolution of 400 µm and 80 µm, respectively.
Organic-inorganic and all-inorganic lead halide nanoparticles [Invited]
2015
Organic-inorganic (hybrid) and all-inorganic lead halide perovskites, in particular APbX(3) where A is an organic cation (methylammonium or formamidinium) or cesium cation and X = Cl, Br, I, respectively, are of great interest in photovoltaic devices and as luminescent materials for light-emitting devices. It has recently been demonstrated that they can be prepared not only as nanoparticulate material by using the pores of mesoporous films, but also as colloidal nanoparticles, which exhibit enhanced optical properties with respect to the bulk material. We summarize here the methods reported for their preparation as well as their optical features. Experimental and theoretical studies on this…
Numerical analysis of light soaking phenomenon in Ruthenium based Dye Sensitized Solar Cells
2017
Dye Sensitized Solar Cells (DSSCs) are widely considered one of the most promising third generation photovoltaic devices, especially thanks to their relatively low cost if compared to conventional solar cells. An interesting phenomenon affecting such devices is the so-called light soaking effect, consisting in the increase of cell main electrical parameters after the exposition to solar light. In this work, starting from the experimental characterization carried out on Ruthenium-based DSSCs, we report on a series of numerical analysis performed to better describe the above-mentioned light soaking effect in order to show the relationship between such phenomenon and the main physical paramete…
Hybrid Inorganic‐Organic White Light Emitting Diodes
2020
This chapter reviews the state of the art of materials, technologies, characterizations, process and challenges concerning hybrid white light‐emitting diodes (LEDs). Here, for a “hybrid LED” we mean a device based on a layer of organic phosphors (or a mix of inorganic and organic ones) pumped by a high‐energy inorganic LED. Light is emitted by a frequency down‐conversion (sometimes simply named color‐conversion) process. Benefits and weak spots of this technology are investigated with a special attention for the materials involved into the process of frequency down‐conversion, in order to envisage the future impact of the hybrid lighting technology among the well‐established inorganic ones.
Investigation of recovery mechanisms in dye sensitized solar cells
2016
Abstract We study the spontaneous recovery phenomenon displayed by solar cells sensitized with a ruthenium complex-based dye N719, which manifests with the increase over the time (from several minutes up to some days) of the short circuit current density J sc and the open circuit voltage V oc , during cell illumination. Under dark conditions the current decreases over time after the application of forward bias voltages. We investigate the effects of temperature and electrolyte composition by means of current–voltage measurements and electrochemical impedance spectroscopy, both under dark and illumination conditions. The main result is that the recovery of the performances depends on the cha…
An aging evaluation of the bearing performances of glass fiber composite laminate in salt spray fog environment
2019
The aim of the present paper is to assess the bearing performance evolution of pinned, glass-composite laminates due to environmental aging in salt-spray fog tests. Glass fibers/epoxy pinned laminates were exposed for up to 60 days in salt-spraying, foggy environmental conditions (according to ASTM B117 standard). In order to evaluate the relationship between mechanical failure mode and joint stability over increasing aging time, different single lap joints, measured by the changing hole diameter (D), laminate width (W) and hole free edge distance (E), were characterized at varying aging steps. Based on this approach, the property-structure relationship of glass-fibers/epoxy laminates was a…
Poor optical stability of molecular dyes when used as absorbers in water-based tissue-simulating phantoms
2019
Biomedical optical systems and models can be easily validated by the use of tissue-simulating phantoms. They can consist of water-based turbid media which often include inks (India ink and molecular dyes) as absorbers. Optical stability of commonly exploited inks under the influence of light, pH changes and the addition of TiO2 and surfactant, was studied. We found that the exposure to ultraviolet and visible light can crucially affect the absorption properties of molecular dyes. On average, absorption peaks decreased by 47.3% in 150 exposure hours. Furthermore, dilution can affect ink’s pH and by that, its decay rate under light exposure. When TiO2 was added to the phantoms, all molecular …
Characterization of a new murine retinal cell line (MU-PH1) with glial, progenitor and photoreceptor characteristics
2013
Unlike fish and amphibians, mammals do not regenerate retinal neurons throughout life. However, neurogenic potential may be conserved in adult mammal retina and it is necessary to identify the factors that regulate retinal progenitor cells (RPC) proliferative capacity to scope their therapeutic potential. Müller cells can be progenitors for retinal neuronal cells and can play an essential role in the restoration of visual function after retinal injury. Some members of the Toll-like receptor (TLR) family, TLR2, TLR3 and TLR4, are related to progenitor cells proliferation. Müller cells are important in retinal regeneration and stable cell lines are useful for the study of retinal stem cell bi…