Evaporated and solution deposited planar Sb₂S₃ solar cells: A comparison and its significance

Sb₂S₃ is an alternative emerging material for chalcogenide solar cells. In this paper, we compare planar solar cells in which the Sb₂S₃ absorber was deposited by either thermal evaporation or a solution based process. The planar inorganic solar cell with evaporated Sb₂S₃ has an efficiency of 1.7%. This is much higher than the efficiency of 0.8% for solution deposited Sb₂S₃, and the highest known reported efficiency for a planar Sb₂S₃ solar cell with a CuSCN hole conducting layer. The evaporated Sb₂S₃ film is sulfur-rich, which results in flattening of the film surface after annealing at 300 °C, thereby reducing the likelihood of contact between the Sb₂S₃ and gold contact. In addition, the crystal size of the evaporated Sb₂S₃ film is about 30% larger than that of the solution deposited Sb₂S₃ and has different preferential crystal planes. These features make evaporation a promising deposition method for flat solar cells made from sulfur-based semiconducting materials. Cross section image of the evaporated Sb₂S₃ solar cell with labels for each layer.