The quest for a spin‐polarized organic light‐emitting diode (spin‐OLED) is a common goal in the emerging fields of molecular electronics and spintronics. In this device, two ferromagnetic (FM) electrodes are used to enhance the electroluminescence intensity of the OLED through a magnetic control of the spin polarization of the injected carriers. The major difficulty is that the driving voltage of an OLED device exceeds a few volts, while spin injection in organic materials is only efficient at low voltages. The fabrication of a spin‐OLED that uses a conjugated polymer as bipolar spin collector layer and ferromagnetic electrodes is reported here. Through a careful engineering of the organic/inorganic interfaces, it is succeeded in obtaining a light‐emitting device showing spin‐valve effects at high voltages (up to 14 V). This allows the detection of a magneto‐electroluminescence (MEL) enhancement on the order of a 2.4% at 9 V for the antiparallel (AP) configuration of the magnetic electrodes. This observation provides evidence for the long‐standing fundamental issue of injecting spins from magnetic electrodes into the frontier levels of a molecular semiconductor. The finding opens the way for the design of multifunctional devices coupling the light and the spin degrees of freedom.

The synthesis of ultrathin films (UTFs) of NiFe‐LDHs has been achieved by means of an in situ hydrothermal approach, leading to a flat disposition of the LDH crystallites on the substrate, in clear contrast to the most common perpendicular orientation reported to date. Experimental factors like time of synthesis or the nature of the substrate, seem to play a crucial role during the growing process. The 2D morphology of the NiFe‐LDH crystallites was kept after a calcination procedure, leading to a topotactic transformation into mixed‐metal oxide platelets. Hereby, in order to study the catalytic behavior of our samples, a chemical vapor deposition process is explored upon the as‐synthesized films. In presence of a carbon source (ethylene), these films catalyze a preferential low‐temperature (550 °C) growth of bamboo‐like carbon nanotubes, in stark contrast to the different mixture of carbon nanoforms obtained from the bulk samples. This work opens the door for the development of UTFs based on LDHs, which may be of utmost importance in a wide range of potential applications ranging from magnetic storage, catalysis or biomedical applications, to electrochemical batteries, anti‐corrosion and superhydrophobic coatings.

Electrodeposited thin films of the molecule‐based magnet Cr5.5(CN)12·11.5H2O exhibit a magneto‐optical Kerr effect (MOKE) with large coercive fields at 200 K. As the thickness of the films is reduced to the nanometer scale, the particle size decreases and the magneto‐optical hysteresis becomes relatively large.