CPE-Na-Based Hole Transport Layers for Improving the Stability in Nonfullerene Organic Solar Cells: A Comprehensive Study

Organic photovoltaic (OPV) cells have experienced significant development in the last decades after the introduction of nonfullerene acceptor molecules with top power conversion efficiencies reported over 19% and considerable versatility, for example, with application in transparent/semitransparent and flexible photovoltaics. Yet, the optimization of the operational stability continues to be a challenge. This study presents a comprehensive investigation of the use of a conjugated polyelectrolyte polymer (CPE-Na) as a hole layer (HTL) to improve the performance and longevity of OPV cells. Two different fabrication approaches were adopted: integrating CPE-Na with PEDOT:PSS to create a composite HTL and using CPE-Na as a stand-alone bilayer deposited beneath PEDOT:PSS on the ITO substrate. These configurations were compared against a reference device employing PEDOT:PSS alone, as the HTL increased efficiency and fill factor. The instruments with CPE-Na also demonstrated increased stability in the dark and under simulated operational conditions. Device-based PEDOT:PSS as an HTL reached T80 after 2500 h while involving CPE-Na in the device kept at T90 in the same period, evidenced by a reduced degradation rate. Furthermore, the impedance spectroscopy and photoinduced transient methods suggest optimized charge transfer and reduced charge carrier recombination. These findings collectively highlight the potential of CPE-Na as a HTL optimizer material for nonfluorine OPV cells.

Significant Stability Improvement of Fullerene Organic Photovoltaics via ZnO Film Modification through the Intermittent Spray Pyrolysis Technique

Morphological control of the layers within the bulk heterojunction organic photovoltaics (BHJ-OPVs) is a key feature that governs their performance. In the present work, we demonstrate that zinc oxide-ZnO-interlayers sprayed via the intermittent spray pyrolysis technique, employing a low-concentration precursor solution, can yield inverted BHJ-OPVs as efficient as the standard reported ones using the conventional laboratory-scale spin-coating technique. However, we record a pioneer stability behavior of the fabricated inverted fullerene organic photovoltaics (iF-OPVs) with various sprayed ZnO conditions. Thus, after optimizing the sprayed ZnO interfacial layer morphology for the inverted PTB7-Th:PC₇₀BM devices, by carefully inspecting the interdependence between the sprayed ZnO thin film morphology and the figures of merit of the optimized iF-OPVs, we conducted a distinct analysis on the optical and electronic properties of the fresh and degraded devices using external quantum efficiency measurements and impedance spectroscopy. Hence, we showed that the most proper ZnO microstructural morphology was obtained by spraying 25 running cycles (25R). Remarkably, we observed that 25R-ZnO-based iF-OPV devices showed a stunning stability behavior and maintained 85% of their initial power conversion efficiency even after 16.7 months without encapsulation in a dry nitrogen glovebox, demonstrating an excellent shelf stability. Accordingly, this approach might facilitate the scalability of inverted OPVs for industrial production visibility.

The acceptability of using IUDs among Egyptian nulliparous women: a cross-sectional study

Background

Although intrauterine contraceptive device is highly effective, safe, long term and reversible method of contraception, the general population and physicians refuse. IUDs for nulliparous women due to persistent rumors about its side effects and complications. The aim of this study was to assess the acceptability of IUD use in nulliparous women by both women and health care providers in Egypt.

Methods

Five hundred thirty nulliparous women and 200 physicians were interviewed in 10 family planning clinics in Suez and Minia cities – Egypt. The knowledge and attitudes of women and health care providers towards IUD use in nulliparous women were assessed through a well designed questionnaire over 2 years. Those women who accepted using IUD were then followed up for 6 months.

Results

Most of nulliparous women sought for contraception reported a negative impression of IUD method (96.2%). 82.5% of physicians had the same attitude. The reasons for refusing IUD among nulliparous women are fear of side effects including infection (52.8%), and bleeding (37.7%).Also, fear of subsequent infertility 51.9% of women. Regarding the providers, increased pelvic inflammatory disease (PID) represented the highest percentage (70%) for non acceptability, followed by difficult insertion (52.5%). Ninety women who accepted use IUD were followed up 6 months later, 94.4% were still using the method and77.8% were happy with the results.

Conclusion

The main barriers that hinder the use of IUD in nulliparous women are the women insufficient knowledge and attitude of their physicians. Good client counseling. Good training for physician to improve their experience would help increase the use of such effective and safe method.

3D hierarchical graphene/CNT with interfacial polymerized polyaniline nano-fibers

In this work Polyaniline (PANI) fiber has been synthetized by the interfacial polymerization method. The thermal behavior of graphene - multiwall carbon nanotubes (MWCNs) composite material (C-Mix) blended with PANI fiber was investigated. Graphene was prepared by thermal reduction of the fabricated graphene oxide (GO) using modified Hummers' method. SEM measurement reveals that MWCNTs were well organized within 2D large surface area graphene nano-sheets to form 3D carbon-base hierarchical structure, and PANI was mixed as a binder polymer matrix. Structural measurements confirm the formation of wide area graphene sheets with crumples, wrinkles, and folds around the edges. Transmission electron microscopy (TEM) images agreed with the well distribution of CNTs within graphene nano-sheets. Also, the surface morphology of the synthesized composites has a spherical regular agglomeration of PANI granular structure on wide area graphene nano sheets with CNT embedded. The change in the existed phonon modes of the fabricated nano-composite was analyzed using Raman spectroscopy. Moreover, Seebeck coefficient changes from +132.4 μV/K to -10.3 μV/K after adding carbon-based materials which reflects the reverse of predominate carriers by doping PANI with carbon-based material. It has been noticed that there is an enhancement of thermal conductivity of the fabricated composite with respect to neat polymer. Hence, we propose that 3D carbon structure with PANI construct a stable N-Type thermoelectric material.

Effect of head-neck position on elbow flexor muscle torque production

The purpose of this study was to investigate whether the tonic neck reflex affects elbow flexor muscle torque production in healthy, young adults and which head-neck (H-N) positions have the greatest influence. Forty-eight male and female students between the ages of 18 and 35 years volunteered as subjects. Head-neck positions involving the sagittal and horizontal planes and combinations of these were tested. The nondominant hand was used to apply tension to the lever of an isokinetic analyzer under both isometric (static) and isotonic (dynamic) conditions. Peak torque was determined for each H-N position under each condition. Differences in peak torque were elicited more easily from the female subjects than from the male subjects. Head-neck rotation (horizontal plane) appeared to have a greater influence on elbow flexor muscle torque production than movements in the sagittal plane, particularly when movements in the two planes were combined. We concluded, therefore, that H-N position must be considered during rehabilitation of the upper extremity.

Isolation, characterization and distribution of adenosine 3':5'-cyclic monophosphate from Pinus radiata

Cyclic AMP was extracted in 0.1 M-HCl from tissues of Pinus radiata and purified by gel filtration on Sephadex G-10, and chromatography on Dowex AG1 (X2) and polyethyleneimine-cellulose in two separate solvent systems. Presumptive cyclic AMP from 10kg batches of pine needles was characterized by countercurrent distribution in the presence of cyclic [8-3H]AMP. Statistical analysis of the curves for radioactivity and mass (determined by the Gilman competitive-binding assay) showed that the fit of the curves was highly significant for seven degrees of freedom. The distribution of cyclic AMP within P. radiata and various other plant tissues was determined by the Gilman procedure. The results suggest that there is no relationship between variations in cyclic AMP concentrations and the known function of the tissue in which it was measured.

Binding of (3H)dihydroalprenolol to beta adrenoceptors of cells isolated from adult rat heart

Myocardial cells isolated from adult rat heart bind (3H)dihydroalprenolol. Sixty-one percent of this binding appeared to be at the beta adrenoceptors since it was inhibited by saturating quantities of the beta antagonist propranolol or by the beta agonist isoprenaline. The binding is stereoselective as the l-isomer of isoprenaline caused greater inhibition than the d-isomer. The binding of (3H)dihydroalprenolol to beta adrenoceptors was saturable; half maximum binding occurred at about 8 nM and full saturation at 30--40nM.

Cyclic AMP formation and morphology of myocardial cells isolated from adult heart: effect of Ca2+ and Mg2+

Adult rat heart cells were isolated by perfusion with a calcium-free phosphate buffer containing collagenase. Optimal conditions gave a high proportion of elongated cells. Isoprenaline increased cydic AMP content linearly, with ED50 (dose effective in 50% of the population) about 10(-7) M. Ca2+ made the cells spherical, and it nearly abolished cyclic AMP response as did lack of Mg2+.

Effect of adenine nucleotides on NAD-dependent isocitrate dehydrogenases in rhizobia and bacteroids of legume root nodules

ATP, ADP, AMP and cyclic AMP inhibit NAD-dependent isocitrate dehydrogenase (L-s-isocitrate : NAD-+ oxidoreductase, EC 1.1.1.41) from rhizobia but have no effect on the enzyme from corresponding bacteroids. This was observed using three rhizobial strains two of which are effective, and one ineffective, with Lotus pedunculatus. Using partially purified enzyme from each of the three rhizobial strains it was found that the adenine nucleotides inhibit the enzyme by competing with NAD-+, not with isocritrate. The rate of reaction catalysed by the enzyme (expressed as activity per mg protein) in cell-free extracts of each of the effective rhizobial strains was about three times that of the reaction in extracts of the corresponding bacteroids. No correlation was found between effectiveness and NAD-dependent isocitrate dehydrogenase activity in the rhizobial cells.