A cobalt(ii)heteroarylalkenolate precursor for homogeneous Co 3 O 4 coatings by atomic layer deposition.

We present a new and efficient cobalt precursor, CoII (DMOCHCOCF3 )2 , to prepare Co3 O4 thin films and conformal coatings. In the synthesis of this Co complex, heteroaryl moieties and CF3 -groups were combined leading to the precursor with high thermal stability and volatility. The suitability of this precursor for ALD deposition was tested on flat silicon substrates and TiO2 /C nanofibers upon process optimization. Deposition at 200 °C results in homogeneous and smooth Co3 O4 thin films with a growth rate of 0.02 nm per cycle. Conformal coatings have been successfully obtained on TiO2 /C nanofibers, making them an attractive platform for surface chemistry studies on high aspect ratio structures for future photocatalysts, sensors, supercapacitors and batteries.