Layered V₂O₅ hydrate has been applied as the hole transport layer (HTL) in organic solar cells (OSCs). V₂O₅ is obtained from a sodium metavanadate solution in water under ambient conditions, resulting in a final thin film of formula V₂O₅·0.5H₂O. The 0.5 water molecules are not removed from the V₂O₅ layered structure unless the sample is heated above 250 °C, which makes the thin film highly stable under real working conditions. The HTL was used in OSCs in the normal and the inverted configurations, applying metallic Ag as the back-metal electrode in both cases. Fabrication of both OSC configurations completely by solution-processing printing methods in air is possible, since the Al electrode needed for the normal-configuration OSC is not required. The work function (WF) and band gap energy (BG) of the V₂O₅ thin films were assessed by XPS, UPS and optical analyses. Different WF values were observed for V₂O₅ prepared from a fresh V₂O₅–isopropanol (IPA) solution (5.15 eV) and that prepared from a 24 h-old solution (5.5 eV). This difference is due to the gradual reduction of vanadium (from V⁵⁺ to V⁴⁺) in IPA. The OSCs made with the V₂O₅ thin film obtained from the 24 h-old V₂O₅–IPA solution required photo-activation, whereas those made with the freshly obtained V₂O₅ did not. Outdoor stability analyses of sealed OSCs containing a V₂O₅ HTL in either configuration revealed high stability for both devices: the photovoltaic response at T₈₀ was retained for more than 1000 h.

In this work, we report magnetoelectric coefficient measurements in $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ (BFO) compounds using dynamic lock-in technique to evidence magnetoelectric coupling behavior. The response of the magnetoelectric coefficient shows rapid increase from low frequencies $\left(0.1\mathrm{kHz}\right)$ to around $5\mathrm{kHz}$ , reaching a maximum, and then decreasing monotonously to $100\mathrm{kHz}$ . For a constant frequency at $7\mathrm{kHz}$ , the maximum magnetoelectric coefficient was close to $7\mathrm{mV}∕\mathrm{cm}\mathrm{Oe}$ , obtained at a bias magnetic field of $H=120\mathrm{Oe}$ . Thus, we demonstrated the feasibility of this technique for characterizing multiferroic materials.

We report a new strategy to grow nano-columnar La ₂ NiO ₄ thin films with an enlarged specific surface area. In combination with modifications of the surface chemistry, we strongly improved the oxygen exchange activity of this promising electrode material.

The possibility to fabricate freestanding single crystal complex oxide films has raised enormous interest to be integrated in next‐generation electronic devices envisaging distinct and novel properties that can deliver unprecedented performance improvement compared to traditional semiconductors. The use of the water‐soluble Sr₃Al₂O₆ (SAO) sacrificial layer to detach the complex oxide film from the growth substrate has significantly expanded the complex oxide perovskite membranes library. Nonetheless, the extreme water sensitivity of SAO hinders its manipulation in ambient conditions and restricts the deposition approaches to those using high vacuum. This study presents a pioneering study on the role of Ca‐substitution in solution processed SAO (Sr_3−xCa_xAl₂O₆ with x ⩽ 3) identifying a noticeable improvement on surface film crystallinity preserving a smooth surface morphology while favoring the manipulation in a less‐restricted ambient conditions. Then, the study focuses on the effect of the sacrificial composition on the subsequent ex situ deposition of La_0.7Sr_0.3MnO₃ (LSMO) by pulsed laser deposition, to obtain epitaxial films with a variable degree of strain. Finally, epitaxial and strain‐free LSMO membranes with metal‐insulator transition at 290 K are delivered. This study offers a hybrid and versatile approach to prepare and easily manipulate crystalline perovskite oxide membranes by facilitating ex situ growth on SAO‐based sacrificial layer.

We have investigated the magneto-optical response in the visible spectrum of thin-film ferromagnetic manganites. We observe a huge enhancement of the magnetorefractive effect (MRE) around the Curie temperature, which is linked to the colossal magnetoresistance. It is found that the unusually large MRE at visible frequencies is accompanied by an increase in the magnetic field of the optical conductivity. We argue that these remarkable phenomena are related to the field-induced suppression of Jahn-Teller dynamical charge localization.