Synthesis and Characterization of Peripherally Ferrocene-modified Zinc Phthalocyanine for Dye-sensitized Solar Cell

Abstract

Synthesis and structural characterization of peripherally ferrocene-substituted zinc phthalocyanine (ZnPc-Fc) were carried out for efficient far-red/near-IR performance in dye-sensitized nanostructured TiO2 solar cells. Incorporating ferrocene into phthalocyanine strongly improved the dye solubility in polar organic solvents, and reduced surface aggregation due to the steric effect of bulky ferrocene substituents. The involvement of electron transfer reaction pathways between ferrocene and phthalocyanine in ZnPc-Fc was evidenced by completely quenched fluorescence from S1 state (< 0.08% vs ZnPc). Strong absorption bands at 542 and 682 nm were observed in the transient absorption spectroscopy of ZnPc-Fc in DMSO, which was excited at a 670 nm laser pulse with a 15 ps full width at half maximum. Also, the excited state absorption signals at 450 -600 and 750 -850 nm appeared from the formation of charge separated state of phthalocyanine's anion. The lifetime of the charge separate state in ZnPc-Fc was determined to be 170 ± 8 ps, which was almost 17 times shorter than that of the ZnPc.

Synthesis and Charge-Transfer Dynamics in a Ferrocene-Containing Organoboryl aza-BODIPY Donor–Acceptor Triad with Boron as the Hub

“…The preparation of highly efficient functional materials for solar energy conversion is of fundamental interest. − Because of their outstanding absorption properties, numerous porphyrinoids coupled with organic or organometallic donor fragment(s) have been investigated in dye-sensitized solar cells and organic photovoltaics. − The photophysical properties of ferrocenylporphyrins, phthalocyanines, tetraazaporphyrins, and subphthalocyanines have recently been investigated by several research groups, and the ferrocene (Fc)-based substituents were found to be prominent electron-donating groups. − BODIPYs and aza-BODIPYs (where BODIPY = dipyrrometheneboron difluoride) have recently emerged in this field because of their unique photophysical properties. − Several Fc-containing BODIPY conjugates with a Fc group linked via a spacer located at the α- or β-pyrrolic or meso position have been reported. − However, to the best of our knowledge, no reports are available on BODIPYs and aza-BODIPYs with Fc substituents connected via the central boron atom using direct organometallic B–C bonds. Bonding the Fc ligands at the boron atom leaves them in close proximity to aza-BODIPY but without conjugated through-bond coupling.…”

Electrolyte-Free Dye-Sensitized Solar Cell with High Open Circuit Voltage Using a Bifunctional Ferrocene-Based Cyanovinyl Molecule as Dye and Redox Couple

“…The redox couple electrolyte subsequently reduces the dye molecule to its ground state while the electrolyte is regenerated at the counter electrode, resulting in open circuit voltage ( V OC ) and short circuit current ( J SC ). Recently, Daeneke et al reported a DSSC study using ferrocenyl derivatives as redox electrolytes to understand the variation of dye regeneration efficiency with the change in ferrocene/ferrocenium redox potential . This and a handful of other reports showed that ferrocenyl compounds are mostly used as redox couples and have never been used as effective sensitizers in DSSC due to their comparatively larger band gap that can only absorb a very small part of the solar spectrum .…”

“…Recently, Daeneke et al reported a DSSC study using ferrocenyl derivatives as redox electrolytes to understand the variation of dye regeneration efficiency with the change in ferrocene/ferrocenium redox potential . This and a handful of other reports showed that ferrocenyl compounds are mostly used as redox couples and have never been used as effective sensitizers in DSSC due to their comparatively larger band gap that can only absorb a very small part of the solar spectrum . Thus, designing a ferrocenyl derivative that can absorb a significant part of visible light that could not only act as a photon absorber but also, because of its intrinsic redox properties, would be able to regenerate the dye after the photogenerated electron has been transferred to the TiO 2 layer would obviate any additional redox electrolyte in the solar cell device.…”

Large-Scale Preparation of 1,1′-Ferrocenedicarboxylic Acid, a Key Compound for the Synthesis of 1,1′-Disubstituted Ferrocene Derivatives

“…It should be noted that most previous protocols for the syntheses of the diesters 2 Et and 2 Me involved esterification of fc(COOH) 2 ( 4 ), ,, while here the opposite approach was pursued, with the ester 2 Et serving as a precursor for the preparation of 4 . Hence, saponification of the diester 2 Et on scales up to 150 g was performed at elevated temperature by addition of aqueous NaOH solution to an ethanol solution of 2 Et , producing the sodium salt fc(COONa) 2 , which was isolated by filtration, dissolved in water, and protonated by addition of concentrated HCl.…”