Optimization of the electrical performances in Solid Oxide Fuel Cells with room temperature sputter deposited Gd0.1ce0.9o1.95 buffer layers by controlling their granularity via the in-air annealing step

Large Area Deposition by Radio Frequency Sputtering of Gd0.1Ce0.9O1.95 Buffer Layers in Solid Oxide Fuel Cells: Structural, Morphological and Electrochemical Investigation

“…The sputtering target dimension, the plasma active area, the target–substrate distance, the partial pressure of the operating gas (usually Ar) and the power applied to sustain the discharge are the parameters that typically influence the thickness and the density’s homogeneity during the sputtering process. In the case of the system used for this experiment, previous studies made it possible to select these parameter values in order to optimize the homogeneity and the density of the deposited DC layers on a 35 mm diameter circular SOFC [ 7 , 8 ]. The typical deposition process of the DC barrier layers used a 400 W power discharge in a 2.3 × Torr Ar pressure.…”

“…The typical deposition process of the DC barrier layers used a 400 W power discharge in a 2.3 × Torr Ar pressure. All the as-grown samples underwent an in air post-growth thermal treatment in a quartz tube furnace, using the temperature ramp reported in [ 8 ].…”

“…), Physical Vapour Deposition (PVD)-based techniques have recently attracted interest in relation to the production of DC barrier layers [ 5 , 6 ]. The use of a particular PVD technique, namely room temperature RF-Sputtering, followed by an optimized post-growth annealing, has been shown to ameliorate 35 mm-diameter SOFC button cells’ final performances when compared to cells with commercially screen-printed barrier layers [ 7 , 8 ]. Although other sputtering techniques [ 9 , 10 , 11 ] have been shown to produce DC buffer layers with good structural and electrical properties, the choice of room temperature RF sputtering is, in this case, justified by the very low thickness of the produced DC films and by the ease in scaling up sputtering processes without the need to heat large substrates during the deposition.…”

“…Although other sputtering techniques [ 9 , 10 , 11 ] have been shown to produce DC buffer layers with good structural and electrical properties, the choice of room temperature RF sputtering is, in this case, justified by the very low thickness of the produced DC films and by the ease in scaling up sputtering processes without the need to heat large substrates during the deposition. Moreover, the fine tuning of the post annealing ramp’s temperature made it possible to control the final granularity barrier layer and, hence, the ratio between the number of grain boundaries versus the bulk part of the grain, yielding a further improvement in the electrochemical performance of the cells [ 8 ].…”

“…The results in [ 7 , 8 ] opened the way for additional investigation of this technique in view of the possibility of scaling up to industrial production. Although, at present, the sputtering technique is largely used in many coating-related industrial processes, the area over which sputtered thin films display good homogeneity in terms of thickness and density is strongly dependent on the particular characteristics of the deposition system.…”