Influence of selenium growth condition on the photovoltaic conversion efficiency of Sb₂Se₃ as the solar cell absorption layer

The influences of the selenium (Se) growth condition on the electronic level structure including deep defects and further on the photovoltaic conversion efficiency of antimony selenide (Sb₂Se₃) as the solar cell absorber layer are investigated by controlling the Se powder content during the vapor transport deposition process. The detailed characterizations including X-ray diffraction, Raman, optical absorption and photoluminescence reveal that the deep defects including the Se vacancies on the Sb₂Se₃ surface are largely reduced, and the efficiency of Sb₂Se₃ solar cells can be significantly improved, e.g., by about 31% from 5.1% to 6.7% after adding excessive Se powder during the growth process. This result may provide a basic guideline for improving the efficiency of Sb₂Se₃ solar cells during the growth process of the Sb₂Se₃ absorption layer.