Impact of Graphene Monolayer on the Performance of Non-Conventional Silicon Heterojunction Solar Cells with MoO Hole-Selective Contact.

In this work, a new design of transparent conductive electrode based on a graphene monolayer is evaluated. This hybrid electrode is incorporated into non-standard, high-efficiency crystalline silicon solar cells, where the conventional emitter is replaced by a MoO selective contact. The device characterization reveals a clear electrical improvement when the graphene monolayer is placed as part of the electrode.

Nanospheres of silica with an epsilon-Fe2O3 single crystal nucleus.

A route to produce single crystals of epsilon-Fe(2)O(3) individually wrapped in a silica shell is presented. Formation of epsilon-Fe(2)O(3)/silica nanospheres was achieved by controlled recrystallization of maghemite particles confined in silica shells via calcination in air. Phase transition was monitored by X-ray diffraction, magnetometry, and transmission electron microscopy.

Stabilization of metastable phases in spatially restricted fields: the case of the Fe2O3 polymorphs.

In this work we show how the confinement of particles in a silica matrix with pores, acting as nano-vessels, plays an important role in the formation of pure E-Fe2O3 nanoparticles and their thermal stability. In particular, a HRTEM study of a series of Fe2O3-SiO2 xerogels annealed at different temperatures reveals that, at low temperatures, gamma-Fe2O3 nanoparticles are formed and only transform to F-Fe2O3 after subsequent annealing at higher temperatures. These data are complemented by measurements of the SiO2 matrix porosity as well as with calorimetric and structural analysis of the nanoparticles after matrix removal.

Relaxometric and magnetic characterization of ultrasmall iron oxide nanoparticles with high magnetization. Evaluation as potential T1 magnetic resonance imaging contrast agents for molecular imaging.

Here we report on the synthesis of ultrasmall gamma-Fe2O3 nanoparticles (5 nm) presenting a very narrow particle size distribution and an exceptionally high saturation magnetization. The synthesis has been carried out by decomposition of an iron organometallic precursor in an organic medium. The particles were subsequently stabilized in an aqueous solution at physiological pH, and the colloidal dispersions have been thoroughly characterized by complementary techniques.