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In this work, an assembly of FTO/α-Fe2O3/PB|M+ electrolyte|PB/α-Fe2O3/FTO (M+ = Li+, Na+, K+) secondary photocell was done to improve the charge capacity in the presence of illumination. Our previous results with these electrodes demonstrated the possibility of transferring photogenerated carriers from hematite to Prussian blue. This cell was characterized by incident photon-to-current efficiency (IPCE) and galvanostatic charge/discharge measurements under illumination and compared in darkness. A higher IPCE when potassium ions are employed in the cell was founded, which suggests an easy insertion/desertion of these ions inside/outside of the hexacyanometallate framework, related to the more compact water coordination sphere for this ion. The voltage cell increased when the system was charged under illumination, indicating an increase in the oxidation/reduction of iron centers in the hexacyanometallate structure due to the increase of photogenerated carriers in hematite. The cell's specific capacity reaches around 12% of the theoretical capacity, with a voltage close to the theoretical (1.5 V) and about 95% of coulombic efficiency when the cell was charged and discharged at longer times (8 h). [ABSTRACT FROM AUTHOR]

In this study, we examined the synthesis of Prussian blue onto p-Si(100). The Prussian blue formation was carried out by means of the deposition of a Fe film and then its dissolution in presence of potassium hexacyanoferrate(II). In the first stage, a study by cyclic voltammetry was carried out, and then, using the potential step method, the corresponding nucleation and growth mechanism were determined. Likewise, a morphologic analysis of the deposits obtained at different potential values by means of atomic force microscopy was carried out. The results are consistent with a 3D progressive nucleation with diffusion-controlled growth. Finally, this research is oriented to construct electrochemical storage devices which can be in situ loaded by the photovoltaic action of the semiconductor base material doped silicon. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) can be deposited from colloidal solutions (5.4 × 10 mol L, 0.01 mol L KNO) on glassy carbon, either by potential cycling or potentiostatically, provided that the deposition potential is more positive than −0.2 V vs. Hg/HgCl. Depending on the deposition potential, the PB particles form either a single layer of Everitt's salt, of PB, or multilayers of Berlin green. Also depending on the electrode potential, the deposition was accompanied by currents which were either only of capacitive nature, or represent the sum of capacitive and faradaic currents. The currents were always limited by the diffusion of the colloidal particles to the electrode surface, i.e., they obeyed the Cottrell equation. The PB layers were characterized by in situ atomic force microscopy. [ABSTRACT FROM AUTHOR]

This study addresses the synthesis and characterization of iron(III) hexacyanoferrate(II) (Prussian blue, PB) deposited on a semiconductor hematite electrode (α-Fe 2 O 3). The formation of the Prussian blue/hematite interface was carried out by cyclic voltammetry. The modified electrode was morphologically characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), structurally by x-ray diffraction (XRD), and photoelectrochemically by cyclic voltammetry under polychromatic illumination. The structure of the electrode system shows a cauliflower type morphology, with the typical PB structure. The electrochemical characterization indicates an increase of the currents of the low- and high-spin iron systems of PB when the system is illuminated, indicating that photogenerated charge carriers are involved. • The photogenerated charge carriers in α-Fe 2 O 3 can be transferred to Prussian blue increasing the charge of the redox process. • The electrochemical deposition of Prussian blue (PB) on α-Fe 2 O 3 shows a morphology cauliflower type like. • The stability of PB redox signals on α-Fe 2 O 3 depend on the extension of the potential window applied on electrode system. [ABSTRACT FROM AUTHOR]