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Organic-inorganic lead halide perovskite phases segregate (and their structures degrade) under illumination, exhibiting a poor stability with hysteresis and producing halide accumulation at the surface.In this work, we observed structural and interfacial dissociation in methylammonium lead iodide (CH NH PbI ) perovskites even under dark and vacuum conditions. Here, we investigate the origin and consequences of self-degradation in CH NH PbI perovskites stored in the dark under vacuum. Diffraction and photoelectron spectroscopic studies reveal the structural dissociation of perovskites into PbI , which further dissociates into metallic lead (Pb ) and I ions, collectively degrading the perovskite stability. Using TOF-SIMS analysis, AuI formation was directly observed, and it was found that an interplay between CH NH , I , and mobile I ions continuously regenerates more I ions, which diffuse to the surface even in the absence of light. Besides, halide diffusion causes a concentration gradient between Pb and I and creates other ionic traps (PbI , PbI ) that segregate as clusters at the perovskite/gold interface. A shift of the onset of the absorption band edge towards shorter wavelengths was also observed by absorption spectroscopy, indicating the formation of defect species upon aging in the dark under vacuum.

Tungsten‐doped Ni−Fe hydroxides fabricated on a three‐dimensional nickel foam through cathodic electrodeposition are proposed as effective oxygen evolution reaction (OER) catalysts for alkaline water oxidation. Incorporating an adequate amount of W into Ni−Fe hydroxides modulates the electronic structure by changing the local environment of Ni and Fe and create oxygen vacancies, resulting in abundant active sites for the OER. The optimized electrocatalyst, with a substantial number of catalytic sites, is found to outperform the well‐established 20 wt% Ir/C electrocatalyst. The catalyst only requires small overpotentials of 224 mV and 251 mV to generate current densities of 10 mA cm−2 and 50 mA cm−2, respectively, at an extremely low Tafel slope. Surface study after long‐term chronopotentiometry (ca. 30 h) reveals that the tungsten dopant undergoes reduction to stabilize the Ni and Fe active sites for predominant water oxidation. This research provides new insight to apply optimum amounts of tungsten doping to enable more significant electronic coupling within Ni−Fe for the chemisorption of hydroxy and oxygen intermediates and greatly improved OER activity.

The stability and performance of supercapacitor devices are limited by the diffusion-controlled redox process occurring at materials’ surfaces. Phosphate-based metal oxides could be effectively used as pseudocapacitors because of their polar nature. However, electrochemical energy storage applications of Mn–Co-based phosphate materials and their related kinetics studies have been rarely reported. In this work, we have reported a morphology-tuned Mn x Co 3– x (PO 4 ) 2 ·8H 2 O (MCP) spinel compound synthesized by a one-step hydrothermal method. Detailed physical and chemical insights of the active material coated on the nickel substrate are examined by X-ray diffraction, field-emission scanning electron microscopy, field-emission transmission electron microscopy, and high-resolution X-ray photoelectron spectroscopy analyses. Physiochemical studies reveal that the well-defined redox behavior usually observed in Co 2+ /Ni 2+ surface-terminated compounds is suppressed by reducing the divalent cation density with an increased Co 3+ and Mn 3+ surface states. A uniform and dense leaflike morphology observed in the MnCo 2 phosphate compound with an increased surface area enhances the electrochemical energy storage performance. The high polar nature of P–O bonding formed at the surface leads to a higher rate of polarization and a very low relaxation time, resulting in a perfect square-shaped cyclic voltagram and triangular-shaped galvanostatic charge and discharge curve. We have achieved a highly pseudocapacitive MCP, and it can be used as a vital candidate in supercapacitor energy storage applications.

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Nitrogen-doped porous carbon materials have excellent ORR activities due to their synergistic effects caused by the electron-accepting ability of the adjacent sp² bonded carbon atoms leading to the redistribution of charge density.

The conducting metallic grid is a prominent viable candidate for an alternative to indium tin oxide for optoelectronic devices. This metallic grid tends to oxidize quickly, and to avoid oxidization, a passivation layer must be added, which drastically compromises the transmittance. The fabrication of a highly flexible, highly transparent, and conductive copper grid electrode with an outstanding sheet resistance of 0.11 Ω □−1, and excellent transparency of 93.13% is reported. This copper electrode resists oxidization with the help of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and even after exposing the electrode to the ambient atmosphere, it shows excellent sheet resistance of 0.12 Ω □−1. This is achieved by the in situ formation of an oxidization‐resistive light‐absorbing PEDOT:PSS layer that encapsulates the Cu microparticles during electrodeposition. The electrode shows excellent mechanical stability with good electromagnetic interference shielding of 19 dB. Moreover, the electrode is developed as a thin film heater, and subjects to electrochemical analysis, which shows a specific capacitance of 81.58 mF cm−2 for supercapacitor application.