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The prevalence of background hole doping in tin halide perovskites usually dominates their recombination dynamics. The addition of excess Sn halide source to the precursor solution is the most frequently used approach to reduce the hole doping and reveals photo‐carrier dynamics related to defects activity. This study presents an experimental and theoretical investigation on defects under light irradiation in tin halide perovskites by combining measurements of photoluminescence with first principles computational modeling. It finds that tin perovskite thin films prepared with an excess of Sn halide sources exhibit an enhancement of the photoluminescence intensity over time under continuous excitation in inert atmosphere. The authors propose a model in which light irradiation promotes the annihilation of VSn2−/Sni2+ Frenkel pairs, reducing the deep carrier trapping centers associated with such defect and increasing the radiative recombination. Importantly, these observations can be traced in the open‐circuit voltage dynamics of tin‐based halide perovskite solar cells, implying the relevance of controlling the Sn photochemistry to stabilize tin perovskite devices. [ABSTRACT FROM AUTHOR]

The rational design of heterojunctions based on metal halide perovskites (MHPs) is an effective route to create novel photocatalysts to run relevant solar‐driven reactions. In this work, an experimental and computational study on the synergic coupling between a lead‐free Cs3Bi2Br9 perovskite derivative and g‐C3N4 is presented. A relevant boost of the hydrogen photogeneration by more than one order of magnitude is recorded when going from pure g‐C3N4 to the Cs3Bi2Br9/g‐C3N4 system. Effective catalytic activity is also achieved in the degradation of the organic pollutant with methylene blue as a model molecule. Based upon complementary experimental outputs and advanced computational modeling, a rationale is provided to understand the heterojunction functionality as well as the trend of hydrogen production as a function of perovskite loading. This work adds further solid evidence for the possible application of MHPs in photocatalysis, which is emerging as an extremely appealing and promising field of application of these superior semiconductors. [ABSTRACT FROM AUTHOR]

Water‐stable metal halide perovskites could foster tremendous progresses in several research fields where their superior optical properties can make differences. In this work we report clear evidence of water stability in a lead‐free metal halide perovskite, namely DMASnBr3, obtained by means of diffraction, optical and X‐ray photoelectron spectroscopy. Such unprecedented water‐stability has been applied to promote photocatalysis in aqueous medium, in particular by devising a novel composite material by coupling DMASnBr3 to g‐C3N4, taking advantage from the combination of their optimal photophysical properties. The prepared composites provide an impressive hydrogen evolution rate >1700 μmol g−1 h−1 generated by the synergistic activity of the two composite costituents. DFT calculations provide insight into this enhancement deriving it from the favorable alignment of interfacial energy levels of DMASnBr3 and g‐C3N4. The demonstration of an efficient photocatalytic activity for a composite based on lead‐free metal halide perovskite in water paves the way to a new class of light‐driven catalysts working in aqueous environments. [ABSTRACT FROM AUTHOR]

The peculiar optoelectronic properties of metal‐halide perovskites, partly underlying their success in solar cells and light emitting devices, are likely related to the complex interplay of electronic and structural features mediated by formation of polarons. In this paper the current status of polaron physics in metal‐halide perovskites is reviewed based on a first‐principles computational perspective, which has delivered hitherto noaccessible insights into the electronic and structural features associated with polaron formation in this materials class. The role of organic (dipolar) versus inorganic (spherical) A‐site cations is extensively analyzed, these cations are related to modulation of the energetics and structural extension of polarons in lead‐halide perovskites. Further tuning of polaron energetics is achieved by individual variations in metal (e.g., Pb → Sn) and halide (e.g., I → Br), showing a transition from a semilocalized to a localized polaron regime in which charge holes can be trapped at isolated Sn centers. The vastly varying and tunable nature of charge lattice interactions represents a peculiarity of metal‐halide perovskites that should be taken into account when designing novel materials or targeting specific compositional engineering of existing perovskites. [ABSTRACT FROM AUTHOR]

Objective Premenstrual dysphoric disorder (PMDD) is a mood disorder disrupting social and/or occupational life of affected women. Premenstrual dysphoric disorder etiology is unknown, although a pivotal role is played by the serotoninergic system. Indeed, one of the most effective treatments is selective serotonin reuptake inhibitors. Several studies have proposed a selective serotonin reuptake inhibitor-like role for myo-inositol, likely due to the fact that myo-inositol is the second messenger of serotonin. In the present study, we aimed to investigate the effect of myo-inositol in the treatment of PMDD. Methods We used a two-phase clinical trial approach (phase I: placebo washout; phase II: comparisons between treatment and placebo) and treated PMMD patients with two different myo-inositol formulations: powder or soft gel capsules. We decided to test these two formulations because according to the manufacturer, 0.6 g of myo-inositol in soft gel capsule has a pharmacokinetic equivalent to 2 g of myo-inositol in powder. Results Our results showed a significant improvement of three different scales: a reduction in the Daily Symptoms Records scale and an improvement of the Hamilton Depression Rating and Clinical Global Impression-Severity of Illness scales. Results were similar for both formulations. Conclusions In the present study, by using a new pharmaceutical formulation, we were able to clearly prove the efficacy of myo-inositol in PMDD. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]