Band Gap Variation in Prussian Blue via Cation-Induced Structural Distortion

Abstract

The charge-transfer band gap of the iron cyanide framework material Prussian Blue and its dependence on the type and location of the charge-compensating interstitial cations (K(+), Rb(+), Cs(+)) are investigated via periodic density functional (DF) calculations. The calculated variation in the band gap magnitude with respect to cation type confirms recent experimental results on cation-induced spectral shifts. The role of both the cation interaction with the framework and the cation-induced lattice expansion are examined with respect to their influence on the band gap. The gap magnitude is related to the cation type but is found to be more strongly affected by cation-induced lattice distortion as the cation passes through the material. Our results support the possibility of engineering the electronic structure of Prussian Blue type materials through guest-induced host-framework distortion.

Evidence of Magnetoresistance in the Prussian Blue Lattice during a Voltammetric Scan

“…However, the acoustic impedance of PB films does not change largely because the movement of potassium ions and modifications of the acoustic impedance resistance (motional resistance, R m ) associated to the electrochemical scan between the PB (0.60 V) and ES (-0.20 V) forms are smaller; only a small dip in the N-Fe(III)-N angle is observed in a solution with potassium cations. 41 As a consequence, changes in the resonating microsensors associated to phenomena that are not related to structure or density changes are better monitored by means of variations of motional resistance than by means of variations in the resonance frequency of the EQCM device. For that, the measurement of the motional resistance is used in this work during the voltammetric scan as a magnetic field sensor where the detectable magnetic field range is similar to the range of the magnetic sensors based on the GMR effect.…”

Tailored Assembly of Molecular Water Oxidation Catalysts on Photoelectrodes for Artificial Photosynthesis

“…Metal‐organic frameworks (MOFs), including Prussian blue and its analogues (PBAs), have gained great attention due to their interesting properties originating from their flexibility in structure and synthetic methods, allowing a large degree of structural and chemical tinability . MOFs and PBAs can be prepared by bottom‐up assembly of molecular precursors via the formation of continuous chemical bonding between transition metal ions and ligand molecules (e.g., cyanide CN for PBAs).…”

“…Electrochemical properties of PBAs can be finely tuned by the substitution of N‐ and C‐coordinated transition metal ions, and introducing vacancies , . Even for the same transition metal ions, their redox state can be varied by controlling the types and number of the inserted cations (Figure b) , . Compared to conventional molecular electrocatalysts, which can be deposited in a monolayer through complex chemical modification,, , they (1) can be readily deposited on various electrodes or photoelectrodes by bottom‐up assembly of precursors, (2) allow control over the deposited amount of catalytic active sites beyond a monolayer because of their porous structure and moderate electrical conductivity, and (3) have high stability in a wide pH range, from acidic to slightly basic pHs , , , , …”

“…Metal-organic frameworks (MOFs), including Prussian blue and its analogues (PBAs), have gained great attention due to their interesting properties originating from their flexibility in structure and synthetic methods, allowing a large degree of structural and chemical tinability. [161][162][163] MOFs and PBAs can be prepared by bottom-up assembly of molecular precursors via the formation of continuous chemical bonding between transition metal ions and ligand molecules (e.g., cyanide CN for PBAs). Due to such flexibility in their design and resultant properties, they can have a wide variety of applications including energy storage, [164][165][166][167][168] catalysis, [161,162,[169][170][171][172] and magnetic applications.…”

Mn2+-Doped Prussian Blue Nanocubes for Bimodal Imaging and Photothermal Therapy with Enhanced Performance

“…This red-shifted absorbance in PB:Mn samples could be explained by changes in the electron density and orbital energies of the cyanide bonds due to the presence of Mn 2+ in the lattice[38][39] .NIR lasers are preferred over visible lasers in PTT to achieve deeper tissue penetration. 808 nm is one of the most frequently used wavelengths for NIR lasers used in photothermal tumor ablation.…”