While the susceptibility of CH 3 NH 3 PbI 3 to water is well-documented, the influence of water on device performance is not well-understood. Herein, we use infrared spectroscopy to show that water infiltration into CH 3 NH 3 PbI 3 occurs much faster and at a humidity much lower than previously thought. We propose a molecular model in which water molecules have a strong effect on the hydrogen bonding between the methylammonium cations and the Pb−I cage. Furthermore, the exposure of CH 3 NH 3 PbI 3 to the ambient environment increases the photocurrent of films in lateral devices by more than 1 order of magnitude. The observed slow component in the photocurrent buildup indicates that the effect is associated with enhanced proton conduction when light is combined with water and oxygen exposure.

Josephson junctions with iron pnictides open the way for fundamental experiments on superconductivity in these materials and their application in superconducting devices. Here, we present hybrid Josephson junctions with a BaFe 1.8 Co 0.2 As 2 thin film electrode, an Au barrier and a PbIn counter electrode. The junctions show resistively shunted junction-like current-voltage characteristics up to the critical temperature of the counter electrode of about 7.2 K. The temperature dependence of the critical current shows nearly linear behavior near T C . Well-pronounced Shapiro steps are observed at microwave frequencies of 10−18 GHz. Assuming an excess current of 200 µA at 4.2 K the effective I C R N product calculates to 7.9 µV.

Soft optical components based on flexible polymers or fluids can be coupled to electroactive polymer artificial muscles for monolithically integrated optical elements with voltage controlled properties. A flexible polymer distributed feedback (DFB) dye laser is combined with an electroactive dielectric elastomer actuator to afford continuous voltage‐controlled wavelength shift.

This Letter reports on new methods and a consistent model for voltage tunable optical transmission gratings. Elastomeric gratings were molded from holographically written surface relief gratings in an azobenzene sol-gel material. These were placed on top of a transparent electroactive elastomeric substrate. Two different electro-active substrate elastomers were employed, with a large range of prestretches. A novel finite-deformation theory was found to match the device response excellently, without fitting parameters. The results clearly show that the grating underwent pure-shear deformation, and more surprisingly, that the mechanical properties of the electro-active substrate did not affect device actuation.