Metal chalcogenides, such as Sb2S(e)3, SnS, CdS, and PbS, have been successfully applied as light sensitizers to the inorganic-organic hybrid solar cells. Among them, Sb chalcogenides (Sb-Chs), Sb2S(e)3, are of particular interest because of their excellent optical properties including easily tunable band-gaps by adjustable composition, high molar extinction coefficients, and large intrinsic dipole moments. Very recently, we achieved the high efficiency of ~ 7.5 % in the Sb2S3-sensitized devices via a post-surface-treatment with thioacetamide . However, the photovoltaic performance of the solar cells sensitized with Sb-Chs is still restricted by strong charge recombination (low open circuit voltage VOC) and insufficient light-harvesting (low short circuit current density JSC). Here, we introduce one approach for enhancing both VOCand JSC by applying Sb2(S/Se)3 light sensitizers in the inorganic-organic heterojunction solar cells. The Sb2(S/Se)3 light sensitizers were synthesized either by mixing two single source precursors of Sb2S3/Sb2Se3 or sequential deposition of Sb2Se3/Sb2S3. We observed that the VOC was gradually decreased with increase of JSC as increasing ratio of Se/S in Sb2(S/Se)3. The best cell exhibited high efficiency of ~ 8.1 % with high JSC of 25.8 mA cm-2 and VOC of 530.6 mV. Our efforts towards further improvement in efficiency will pave a new way for highly efficient inorganic-organic hybrid solar cells.
 Y. C. Choi, D. U. Lee, J. H. Noh, E. K. Kim, and S. I. Seok, Highly Improved Sb2S3 Sensitized-Inorganic-Organic Heterojunction Solar Cells and Quantification of Traps by Deep-Level Transient Spectroscopy, Adv. Funct. Mater., 2014, 24, 3587-3592.