Sb2S3 and Cu3SbS4 nanocrystals as inorganic hole transporting materials in perovskite solar cells

One of the key parts of perovskite solar cells which has great influence on their performance and stability is hole transporting layer. Spiro-OMeTAD is extensively used as organic hole transporting material in perovskite solar cells. However, Spiro-OMeTAD is expensive and has low chemical stability. In this study, the solution processed Sb2S3 and Cu3SbS4 nanocrystals have been synthesized and then the n-i-p mesoscopic perovskite solar cells have been fabricated using Spiro-OMeTAD, Sb2S3 and Cu3SbS4 nanocrystals as hole transporting layer at ambient air condition. It is shown that the conduction and valence band levels of the synthesized Sb2S3 and Cu3SbS4 nanocrystals are in the proper positions for using them as hole transporting layer in the perovskite solar cells. The perovskite solar cells fabricated using the Sb2S3 and Cu3SbS4 nanocrystals as hole transporting layer show maximum power conversion efficiency of 8.2% and 13%. Moreover, the non-encapsulated perovskite solar cell with the Cu3SbS4 nanocrystals demonstrates 75% of its initial efficiency while the perovskite solar cell with Spiro-OMeTAD demonstrates 50% of its initial efficiency after 90 days under controlled humidity (<50%) conditions.