Rare-earth doped glasses and light managing in solar cells

Glasses doped with rare earth elements possess unique photoluminescence properties. They find application in several devices, such as lasers, optical amplifiers, and sensors. More recently, rare-earth doped glass thin films have been the subject of investigation for the development of frequency-converting layers able to increase the efficiency of silicon solar cells. Another approach to the improvement of the performance of a solar cell is based on the capture of a larger flux of light by the detector, which can be obtained by surface texture, plasmonics, or waveguide structures. Here, the recent advances in this area will be briefly reviewed

Equilibria of Co(II) and Ni(II) extraction from sulphate solutions with Cyanex 301

The extraction equilibria of Co(II) and Ni(II) extraction from the sulphate solutions with di(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) dissolved in an aliphatic kerosene have been studied. The obtained results prove that the stoichiometry of Co(II) and Ni(II) complexes extracted with Cyanex 301 (HA) corresponds to the following formulae CoA2(HA)2 and NiA2(HA)4, respectively.The logarithmic values of corresponding extractions constants (log Kex,Co and log Kex,Ni) are equal to 2.47±0.03 and 4.73±0.02, respectively. The observed changes of electronic absorption spectra of the organic phases containing cobalt complexes have been attributed to the oxidation of Co(II) in contact with air

Pulse electropolymerization synthesis of PPy(DBS) nanoparticle layers

International audienceA one-step process using a pulse electropolymerization technique is used to fabricate nanoparticles of polypyrrole (PPy) with dodecyl benzene sulfonate (DBS) anions from an aqueous solution without template and without using any chemical additives. The morphology of particles is controlled by changing the pulse duration (from 120 to 0.5 s), while keeping the relaxation time constant at 15 s. Short pulses resulted in the formation of PPy(DBS) nanoparticles with an average particle size of about 50 nm. The control of the size of the PPy(DBS) nanoparticles is ascribed to a pulse electropolymerization growth mechanism, whereby progressive nucleation associated with two-dimensional growth is initiated at each new pulse cycle from the equilibrium electrolyte solution. Short pulses are needed to avoid nonuniform growth of nanoparticles and control the particle size. Sufficiently long relaxation time is required to restore the equilibrium concentrations in the vicinity of the working electrode by suppressing the double layer. Combining short pulses with sufficiently long relaxation times enables the formation of PPy(DBS) nanoparticles. The proposed short-pulse technique is meant to be applied to the fabrication of a wide range of nanostructured conductive polymers