Improving the efficiency of Sb₂Se₃ thin-film solar cells by post annealing treatment in vacuum condition

Sb₂Se₃ thin films prepared by vapor transport deposition (VTD) method have been treated by post annealing process at 200 °C in vacuum condition for 1 h, and the comparative studies between the post annealing treatment (PAT) and without the treatment were carried out. The device efficiency was improved from 4.89% to 5.72% by PAT via the augment of open-circuit voltage and fill factor. Electrical properties from dark J-V and C-V measurements, structural properties from X-ray diffraction, Raman and scanning electron microscope measurements, defect properties from admittance measurements have been compared for the two cell samples. The Sb₂Se₃ cell sample with PAT was found to own less parallel current pathways, larger built-in voltage, better crystalline and lower defects densities, which may account for the efficiency enhancement.