Electrodeposition of Sn-rGO composites involving choline chloride – ethylene glycol ionic liquids with applications in electronics

The paper presents some experimental results regarding the electrodeposition of tin - reduced graphene oxide (Sn-rGO) composite coatings using choline chloride-ethylene glycol eutectic mixtures (denoted ILEG), also known as... [ view full abstract ]

The paper presents some experimental results regarding the electrodeposition of tin - reduced graphene oxide (Sn-rGO) composite coatings using choline chloride-ethylene glycol eutectic mixtures (denoted ILEG), also known as deep eutectic solvents, DESs.

The influence of graphene oxide addition during electrodeposition of Sn from ILEG based electrolyte has been investigated, in order to suppress whiskers growth and to reinforce Sn alloys as lead-free solders.

The Sn-rGO film was electrodeposited on copper substrate from ILEG system containing 0.7M SnCl₂ and 20mL L^-1 N-doped graphene oxide (1mg.mL^-1, dispersion in H₂O), at various applied current densities in the range of 5-30 mAcm^-2 and a temperature of 70°C, under magnetic stirring. Adherent and uniform coatings were obtained.

The characterization of deposits was performed using cyclic voltammetry, current - time transients, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy.

The SEM micrographs showed that the presence of rGO in the deposit (see Fig.1). Moreover, current densities higher than 15 mA cm^-2 are required for an efficient insertion.

The Raman spectra of the electrodeposited Sn-rGO evidence the presence of both G and D bands (at 1584 and 1352 cm^-1, respectively); however, with an increased D/G intensity ratio compared to that in GO. This change suggests that GO is electrochemically reduced (see Fig.2).

Acknowledgements: The work was supported by Romanian Ministry of Education and by Executive Agency for Higher Education, Research, Development and Innovation Funding, under NOVTINALBEST project 38/2016, M Era Net Program.