Electrodeposition of photovoltaic thin films from ionic liquids in ambient atmosphere: Gallium from a chloroaluminate ionic liquid

At present time, semiconductive thin films used in photovoltaic cells can be successfully electrodeposited using ionic liquids in lab scale. However, scaling-up of this technology is hazardous due to the complexity involved to conduct electrodeposition in inert gas atmosphere. This paper reports on a novel approach for electrodeposition of gallium from a chloroaluminate ionic liquid composed of anhydrous aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride (EMIC) in ambient atmosphere, after protection with a non-water-absorbable hydrocarbon layer. Cyclic voltammetry (CV) measurements were undertaken to characterize the electrodissolution and electrodeposition behavior of Ga. Potentiostatic electrodeposition experiments were conducted to deposit functional Ga layers on platinum, nickel, and mild steel substrates. SEM/EDX investigations revealed that Ga deposits have inhomogeneous microstructure developed through the progressive nucleation-growth mechanism that has been controlled by diffusion of Ga cations. (C) 2019 Elsevier B.V. All fights reserved.