The operational stability of perovskite solar cells (PSCs) remains a limiting factor in their commercial implementation. We studied the long-term outdoor stability of ITO/SnO2/Cs0.05((CH3NH3)0.15(CH­(NH2)2)0.85)0.95PbI2.55Br0.45/spiro-OMeTAD/Au cells, as well as the dynamics of their degradation, under simulated sunlight indoors and their recovery in the dark. The extent of overall degradation was found to depend on processes occurring both under illumination and in the dark, i.e., during the daytime and nighttime, with the dynamics varying with cell aging. Full recovery of efficiency in the dark was observed for cells at early degradation stages. Further cell degradation resulted in recovery times much longer than one night, appearing as irreversible degradation under real operational conditions. At later degradation stages, very different dynamics were observed: short-circuit current density and fill factor exhibited a pronounced drop upon light turn-off but strong improvement under subsequent illumination. The interplay of reversible and irreversible degradation processes with different recovery dynamics was demonstrated to result in changes in the cell’s diurnal PCE dependence during its operational lifespan under real sunlight conditions.

The combined use of scanning electron microscopy, Mössbauer spectrometry, X‐ray diffraction and also DC/AC electrical and magnetic characterization techniques allowed this work to elucidate the influence of metal‐to‐dielectric component ration, and effect of oxygen in gas mixture on phase structure and properties of the Co0.45Fe0.45Zr0.10 ferromagnetic nanoparticles in amorphous dielectric Al2O3 matrix. The films of 3–5 µm thickness with compositions of 30 at.% < X < 60 at.% were sputtered on a single substrate from the compound target in the chamber containing either pure Ar or Ar‐O gas mixture. The films sputtered in Ar‐O mixture resulted in partial oxidation of metallic nanoparticles causing the shift of percolation threshold X c to 55 at.% as compared to 45–47 at.% for the samples deposited in pure Ar. Mössbauer studies of the films sputtered in Ar gas have shown that at X < X c metallic nanoparticles were at superparamagnetic state but for X > X c metallic phase showed a ferromagnetic behavior. DC carrier transport at the temperatures of 77–350 K were explained by hopping mechanisms and described by Mott and Shklowski‐Efros laws. That was also confirmed by the relationship power law of Z ′(f ) ∼ f –s (s ≤ 2) for real part of impedance at low temperatures (<120 K) for the samples on dielectric side of MIT. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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intensively investigated and developed at a global level. Among several possible energy storage and power sources, lithium-ion batteries (LIBs) have been successfully used in applications ranging from portable electronic devices to electric vehicles and large-scale energy storage systems (ESSs) owing to their high energy density. However, some critical concerns have arose regarding LIBs such as the cost of lithium resources and safety issues from mobile to ESS applications. [1-6] Thus, rechargeable divalent-ion (e.g., Zn 2+ , Mg 2+ , and Ca 2+) batteries operated in aqueous electrolytes have recently received significant attention because the use of water results in low cost, improved safety, cell fabrication in ambient environment, and reasonable environmental impact. [7-9] Furthermore, the ionic conductivity of aqueous electrolytes for rechargeable divalent-ion batteries is several-ordersof-magnitude higher than that of organic electrolytes. [7,10-12] Among divalent-ion batteries, aqueous zincion batteries (ZIBs) have been intensively investigated owing to the high gravimetric capacity (820 mAh g −1) and sufficient earth abundance of Zn metal. Moreover, the high overpotential of Herein, the promising properties of open-structured NaV 3 O 8 as a cathode material for Zn-ion batteries (ZIBs) are investigated. First-principles calculations predict the insertion of Zn 2+ (0.74 Å) in NaV 3 O 8 with an interlayer distance of ≈7 Å, enabling delivery of a high discharge capacity of 353 mAh g −1 at 70 mA g −1 (0.2 C) for 300 cycles in the operating window of 0.3−1.5 V in 1 m Zn(CF 3 SO 3) 2 aqueous solution. Operando synchrotron X-ray diffraction, X-ray absorption near edge structure spectroscopy, and first-principles calculations validate the insertion of Zn 2+ into the NaV 3 O 8 structure within the operation range. Moreover, operando synchrotron X-ray diffraction and operando Raman spectroscopy reveal the formation of layered zinc hydroxytriflate (Zn 5 (OH) 8 (CF 3 SO 3) 2 •xH 2 O) as a side reaction below 0.8 V on discharge (reduction) and its dissolution into the electrolyte above 0.8 V on charge (oxidation). The formation of the Zn hydroxytriflate interfacial layer increases the charge-transfer activation energy from 15.5 to 48 kJ mol −1 , leading to kinetics fade below 0.8 V. The findings reveal the charge-storage mechanism for NaV 3 O 8 , which may also be applicable to other vanadate cathodes, providing new insights for the investigation and design of ZIBs.

Nanostructured layered bismuth oxysulfide films synthesized by chemical bath deposition reveal a giant incident photon-to-current conversion efficiency (IPCE). This study shows that surprisingly for the cathodic photocurrent in the photoreduction process, the IPCE reaches ≈2500% in aqueous solutions containing [Fe(CN) ] . The giant IPCE is observed starting from a certain minimal oxidizer concentration (c > 10 m for [Fe(CN) ] ) and decreases nonlinearly with an increase of illumination intensity. Giant IPCE is determined by the decrease in resistivity of the bismuth oxysulfide film under illumination with photoconductivity gain, which provides the possibility of charge carriers from an external circuit to participate in the photoreduction process. Giant IPCE is observed not only in [Fe(CN) ] solutions, but also in electrolytes containing other photoelectron acceptors: Fe , I , quinone, H O . In all, solution-processed layered bismuth oxysulfide films offer large-area coverage, nontoxicity, low cost, and compatibility with a wide range of substrates. Abnormally high photoelectrochemical activity, as well as a band gap energy value favorable for efficient conversion of solar light (1.38 eV, direct optical transitions), proves the potential of bismuth oxysulfide photoelectrodes for a new generation of high-performance photoconverters.