Towards anode with low indium content as effective anode in organic solar cells

In2O3 thin films (100 nm thick) have been deposited by reactive evaporation of indium, in an oxygen partial atmosphere. Conductive (σ = 3.5×103 S/cm) and transparent films are obtained using the following experimental conditions: oxygen partial pressure = 1×10−1 Pa, substrate temperature = 300 ◦C and deposition rate = 0.02 nm/s. Layers of this In2O3 thick of 5 nm have been introduced in AZO/In2O3 and FTO/In2O3 multilayer anode structures. The performances of organic photovoltaic cells, based on the couple CuPc/C60, are studied using the anode as parameter. In addition to these bilayers, other structures have been used as anode: AZO, FTO, AZO/In2O3/MoO3, FTO/In2O3/MoO3 and FTO/MoO3. It is shown that the use of the In2O3 film in the bilayer structures improves significantly the cell performances. However the open circuit voltage is quite small while better efficiencies are achieved when MoO3 is present. These results are discussed in the light of surface roughness and surface work function of the different anodes

Identification of genes concordantly expressed with Atoh1 during inner ear development

The inner ear is composed of a cochlear duct and five vestibular organs in which mechanosensory hair cells play critical roles in receiving and relaying sound and balance signals to the brain. To identify novel genes associated with hair cell differentiation or function, we analyzed an archived gene expression dataset from embryonic mouse inner ear tissues. Since atonal homolog 1a (Atoh1) is a well known factor required for hair cell differentiation, we searched for genes expressed in a similar pattern with Atoh1 during inner ear development. The list from our analysis includes many genes previously reported to be involved in hair cell differentiation such as Myo6, Tecta, Myo7a, Cdh23, Atp6v1b1, and Gfi1. In addition, we identified many other genes that have not been associated with hair cell differentiation, including Tekt2, Spag6, Smpx, Lmod1, Myh7b, Kif9, Ttyh1, Scn11a and Cnga2. We examined expression patterns of some of the newly identified genes using real-time polymerase chain reaction and in situ hybridization. For example, Smpx and Tekt2, which are regulators for cytoskeletal dynamics, were shown specifically expressed in the hair cells, suggesting a possible role in hair cell differentiation or function. Here, by reanalyzing archived genetic profiling data, we identified a list of novel genes possibly involved in hair cell differentiation

Estimation of the power absorbed by the surface of optical components processed by an inductively coupled plasma torch

The focus of this work is the determination of the heat flux function -thermal footprint- of a plasma jet generated by an inductively coupled plasma (ICP) torch. The parameters of the heat flux function were determined through the correlation of modelling and experimental results. One surface of substrates was exposed to an impinging jet while the temperature changes of the unexposed surface was recorded, analysed and used to derive the parameters of the heat flux function. From a modelling viewpoint, a series of finite element analyses (FEA) were carried out to predict temperatures of substrate surfaces. From an experimental viewpoint, the plasma torch was powered by a 1 kW radio frequency signal generator tuned at 39 MHz. The ICP torch equipped with a De-Laval nozzle impinged the surfaces of selected substrates at atmospheric pressure. Three sets of experiments -static, single pass and multi passes- were carried out to determine and validate the numerical description of the plasma jet. Also this work enabled to determine the maximum intensity of the heat flux distribution and the total power absorbed by substrate surfaces. Finally, the most advanced numerical model was used to assess the effect of a bi-directional raster scanning strategy that was used for the processing of large optical components

Overactivation of Notch1 Signaling Induces Ectopic Hair Cells in the Mouse Inner Ear in an Age-Dependent Manner

Background: During mouse inner ear development, Notch1 signaling first specifies sensory progenitors, and subsequently controls progenitors to further differentiate into either hair cells (HCs) or supporting cells (SCs). Overactivation of NICD (Notch1 intracellular domain) at early embryonic stages leads to ectopic HC formation. However, it remains unclear whether such an effect can be elicited at later embryonic or postnatal stages, which has important implications in mouse HC regeneration by reactivation of Notch1 signaling. Methodology/Principal Findings: We performed comprehensive in vivo inducible overactivation of NICD at various developmental stages. In CAG CreER+; Rosa26-NICD loxp/+ mice, tamoxifen treatment at embryonic day 10.5 (E10.5) generated ectopic HCs in the non-sensory regions in both utricle and cochlea, whereas ectopic HCs only appeared in the utricle when tamoxifen was given at E13. When tamoxifen was injected at postnatal day 0 (P0) and P1, no ectopic HCs were observed in either utricle or cochlea. Interestingly, Notch1 signaling induced new HCs in a non-cell-autonomous manner, because the new HCs did not express NICD. Adjacent to the new HCs were cells expressing the SC marker Sox10 (either NICD+ or NICDnegative). Conclusions/Significance: Our data demonstrate that the developmental stage determines responsiveness of embryonic otic precursors and neonatal non-sensory epithelial cells to NICD overactivation, and that Notch 1 signaling in the wild type, postnatal inner ear is not sufficient for generating new HCs. Thus, our genetic mouse model is suitable to test additiona

Contribution a l'etude des proprietes de transport dans les bronzes de tungstene orthorhombiques et les bronzes de molybdene au thallium : structure de bandes

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Improvement in the Lifetime of Planar Organic Photovoltaic Cells through the Introduction of MoO3 into Their Cathode Buffer Layers

Recently, MoO3, which is typically used as an anode buffer layer in organic photovoltaic cells (OPVCs), has also been used as a cathode buffer layer (CBL). Here, we check its efficiency as a CBL using a planar heterojunction based on the CuPc/C60 couple. The CBL is a bi-layer tris-(8-hydroxyquinoline) aluminum (Alq3)/MoO3. We show that the OPVC with MoO3 in its CBL almost immediately exhibits lower efficiency than those using Alq3 alone. Nevertheless, the OPVCs increase their efficiency during the first five to six days of air exposure. We explain this evolution of the efficiency of the OPVCs over time through the variation in the MoO3 work function due to air contamination. By comparison to a classical OPVC using a CBL containing only Alq3, if it is found that the initial efficiency of the latter is higher, this result is no longer the same after one week of exposure to ambient air. Indeed, this result is due to the fact that the lifetime of the cells is significantly increased by the presence of MoO3 in the CBL

Semi-Transparent Organic Photovoltaic Cells with Dielectric/Metal/Dielectric Top Electrode: Influence of the Metal on Their Performances

In order to grow semi-transparent organic photovoltaic cells (OPVs), multilayer dielectric/metal/dielectric (D/M/D) structures are used as a transparent top electrode in inverted OPVs. Two different electrodes are probed, MoO3/Ag/MoO3 and MoO3/Ag/Cu:Ag/ZnS. Both of them exhibit high transmission in visible and small sheet resistance. Semi-transparent inverted OPVs using these electrodes as the top anode are probed. The active organic layers consist in the SubPc/C60 couple. The dependence of the OPV performances on the top electrode was investigated. The results show that far better results are achieved when the top anode MoO3/Ag/MoO3 is used. The OPV efficiency obtained was only 20% smaller in comparison with the opaque OPV, but with a transparency of nearly 50% in a broad range of the visible light (400–600 nm). In the case of MoO3/Ag/Cu:Ag/ZnS top anode, the small efficiency obtained is due to the presence of some Cu diffusion in the MoO3 layer, which degrades the contact anode/organic material

Small to large scale mixed turbulent convection: buildings application

International audienc

Numerical analysis of single and multiple jets

The present study aims to use the concept of entropy generation in order to study numerically the flow and the interaction of multiple jets. Several configurations of a single jet surrounded by equidistant 3, 5, 7 and 9 circumferential jets have been studied. The turbulent incompressible Navier-Stokes equations have been solved numerically using the commercial computational fluid dynamics code Fluent. The standard k-ε model has been selected to assess the eddy viscosity. The domain has been reduced to a quarter of the geometry due to symmetry. Results for axial and radial velocities have been compared with experimental measurements from the literature. Furthermore, additional results involving entropy generation rate have been presented and discussed

Improved electron collection in fullerene via caesium iodide or carbonate by means of annealing in inverted organic solar cells

Inverted organic photovoltaic cells (IOPVCs), based on the planar heterojunction C60/CuPc, were grown using MoO3 as anode buffer layer and CsI or Cs2CO3 as cathode buffer layer (CBL), the cathode being an ITO coated glass. Work functions, Φf, of treated cathode were estimated using the cyclic voltammetry method. It is shown that Φf of ITO covered with a Cs compounds is decreased. This decrease is amplified by the annealing. It is shown that the thermal deposition under vacuum of the CBL induces a partial decomposition of the caesium compounds. In parallel, the formation of a compound with the In of ITO is put in evidence. This reaction is amplified by annealing, which allows obtaining IOPVCs with improved efficiency. The optimum annealing conditions is 150 °C for 5 min