Room‐Temperature Photoinduced Electron Transfer in a Prussian Blue Analogue under Hydrostatic Pressure

Abstract

In from the cold: The Co(III)Fe(II) state of a CoFe Prussian blue analogue undergoes a Co(III)-Fe(II) →(Co(II)-Fe(III))* electron transfer at room temperature when irradiated by visible light (532 nm; see scheme). This property was confirmed using energy-dispersive X-ray absorption spectroscopy at the Co and Fe K-edges of the piezo-induced Co(III)Fe(II) state.

Weak Ferromagnetic Interaction at the Surface of the Ferrimagnetic Rb2Co4[Fe(CN)6]3.3·11H2O Photoexcited State

“…CoFe PBAs to characterize and control the electron transfer mechanism and the associated magnetic properties. [15][16][17][18][19][20][21][22][23][24][25] These fascinating photomagnetic properties were found to depend upon the nature and amount of alkali cations inserted in the structure 16,17,20,26 and a series of Rb 2 Co 4-x Zn x [Fe(CN) 6 ] 3.3 PBAs with different stoichiometries has been studied to explore the photo-induced metastable state. 12,13,23 They also devoted a lot of efforts to the investigation of the Rb 2 Co 4 [Fe(CN) 6 ] 3.3 · 11 H 2 O PBA (called RbCoFe in the following), which was chosen as a model compound for the study of the photomagnetic effect because it combines a large photomagnetic effect and a reproducible synthesis.…”

Pressure-tuning of the photomagnetic response of heterostructured CoFe@CrCr-PBA core@shell nanoparticles

“…In other words, although the T N,s of the CrCr-PBA shell shifted to higher temperatures, the T R of the CoFe-PBA core moved to lower temperatures when the pressure was increased. These results provide a guide for future approaches seeking to observe photocontrolled magnetic response at higher temperatures in these kinds of heterostructures, and chemical tuning of the CoFe constituent will play a significant role [17,20,21].…”

“…Irradiation of the dark state establishes the light state in the core by a photo-CTIST process, and this phenomenon is known as photoinduced magnetism (PIM) below the magnetic ordering temperature of the CoFe-PBA near 24 K [34,35]. At higher temperatures, the light state persists as the CoFe spin pairs remain in their paramagnetic (S 0) states until thermally relaxed near 125 K. Finally, the pressure-induced electron-transfer (PIET) effect causes the low volume (S = 0) non-magnetic states of CoFe-PBA to be increased [15][16][17][18], as pressure favors the low volume state causing an increase in the temperature range over which it is established. Of course, it is widely known that external pressure can alter bond distances and angles thereby resulting in modificaitons of the magnetic exchange interactions.…”

“…Using PBA heterostructures, a series of comprehensive studies by several groups have elucidated the robust magnetomechanical coupling at the interface of the two components and the interplay between the size of the cores and the thicknesses of the shells for observing photoinduced changes in the magnetic response [11][12][13][14]. Although the effect of external pressure on the magnetic behavior of several PBAs has been reported, including CoFe-PBA [15][16][17][18] and CrCr-PBA [19] that are the components of the system used in present study, the magnetic changes induced by light and pressure have not been previously reported for PBA heterostructures. Herein, the observed effects of pressure on the magnetic ordering temperatures of the CoFe-PBA core (T N,c ≈ 25 K) 1 and the CrCr-PBA shell (T N,s ≈ 200 K), along with the shift of the temperature where the photo-CTIST of the CoFe-PBA core relaxes (T R ≈ 125 K), are similar to the behaviors reported for the single-phase materials [15,16,18,19].…”

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

“…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. [173][174][175][176] In this chapter, we will focus more closely on PBAs than MOFs because PBAs can be simply and readily synthesized under mild conditions, such as room temperature and aqueous phase. Note that MOFs can typically be assembled from large hydrophobic ligand molecules and thus require additional high temperature and non-aqueous processes.…”