Room-temperature electrical addressing of a bistable spin-crossover molecular system.

Flexible light-emitting electrochemical cells with single-walled carbon nanotube anodes

Abstract In this work, we demonstrate flexible solution processed light emitting electrochemical cells (LECs) which use single-walled carbon nanotubes (SWCNTs) films as the substrate. The SWCNTs were synthesized by an integrated aerosol method and dry-transferred on the plastic substrates at room temperature. The addition of a screen printed poly (3,4-ethylene dioxythiophene) doped with poly (styrene sulfonate) (PEDOT:PSS) film onto the nanostructured electrode further homogenizes the surface and enlarges the work function, enhancing the hole injection into the active layer. By using an efficient phosphorescent ionic transition metal complex (iTMC) as the active material, efficacies up to 9…

Mössbauer thermal scan study of a spin crossover system

Programmable Velocity equipment was used to perform a Mössbauer Thermal Scans to allow a quasi-continuous temperature study of the magnetic transition between the low-spin and a high-spin configurations in [Fe(Htrz)2(trz)](BF4) system. The material was studied both in bulk as in nanoparticles sample forms.

Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.

Nanoparticles of iron(II) triazole salts have been prepared from water-organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30-40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10-15 nm, the spin transition "moves" towards lower temperatures, reaching a 316 K limit for the cooling down transition and mainta…

Bistable spin-crossover nanoparticles showing magnetic thermal hysteresis near room temperature

We have demonstrated that the reverse micelle technique can be applied to polymeric spin-crossover systems, such as [Fe(Htrz)2(trz)](BF4), to control the growth of the crystallites. Small nanoparticles of diameters around 10 nm and narrow size distribution were obtained. It is easy to envision that, by modifying the synthetic procedure, the size and critical temperatures of these nanoparticles can be tuned. On one hand, different ratios of solvent, water, and surfactants will lead to different micelle sizes, which will affect the particle size and, maybe, the magnetic properties. On the other hand, the critical temperatures can be lowered towards room temperature by changing the composition…