A versatile Fe(II) diketonate diamine adduct: preparation, characterization and validation in the chemical vapor deposition of iron oxide nanomaterials

Iron(III) oxide nanomaterials are extremely promising for the development of magnetic devices, gas sensors, photocatalysts, and photoelectrodes for solar water splitting. The fabrication of such systems by chemical vapor deposition (CVD) relies on the use of molecular sources joining shelf-stability, high volatility, and clean decomposition. Herein, we report for the first time on a versatile iron(II) precursor, namely Fe(tfa)2TMEDA (tfa = 1,1,1-trifluoro-2,4-pentanedionate; TMEDA = N,N,N′ ,N′ -tetramethylethylenediamine), combining the above features with a simple molecular concept. A theoretical-experimental characterization confirmed the compound spectroscopic purity and monomeric nature, and enabled to elucidate its structural, vibrational and electronic properties, along with its fragmentation pathway and thermal behavior. The ideal Fe(tfa)2TMEDA characteristics for CVD applications were finally validated through the fabrication of high purity iron oxide nanomaterials. The latter, comprising the sole metastable β-Fe2O3 polymorph rather than the most stable rust (α-Fe2O3), were characterized by the occurrence of oxygen defects and a nano-organization tunable as a function of growth temperature and reaction atmosphere.