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Francesco Tassinari

Publications and source records attributed to Francesco Tassinari.

2 recordsLinked to original sources

Control of Electrons Spin Eliminates Hydrogen Peroxide Formation During Water Splitting

The production of hydrogen through water splitting in a photoelectrochemical cell suffers from an overpotential that limits the efficiencies. In addition, hydrogen-peroxide formation is identified as a competing process affecting the oxidative stability of photoelectrodes. We impose spin-selectivity by coating the anode with chiral organic semiconductors from helically-aggregated dyes as sensitizers; Zn-porphyrins and triarylamines. Hydrogen peroxide formation is dramatically suppressed, while the overall current through the cell, correlating with the water splitting process, is enhanced. Evidence for a strong spin-selection in the chiral semiconductors is presented by magnetic conducting (mc-)AFM measurements, where chiral and achiral Zn-porphyrins are compared. These findings contribute to our understanding of the underlying mechanism of spin selectivity in multiple electron-transfer reactions and pave the way towards better chiral dye-sensitized photoelectrochemical cells.

physics.chem-ph

The temperature-dependent chiral-induced spin selectivity effect: Experiments and theory

The theoretical explanation for the chiral-induced spin selectivity effect, in which electrons' passage through a chiral system depends on their spin and the handedness of the system, remains vague. Although most experimental work was performed at room temperature, most of the proposed theories did not include vibrations. Here, we present temperature-dependent experiments and a theoretical model that captures all observations and provides spin polarization values that are consistent with the experimental results. The model includes vibrational contribution to the spin orbit coupling. It shows the importance of dissipation and the relation between the effect and the optical activity.

cond-mat.mes-hall