Efficiency improvement for perovskite-inspired Cs₃Sb₂I₉solar cells using P3HT as the hole transport material

In this work, we introduce P3HT (poly(3-hexylthiophene-2,5-diyl)) as an efficient hole transport material (HTM) for lead-free Cs₃Sb₂I₉perovskite-inspired solar cells. The P3HT doubles the power conversion efficiency (PCE) of the solar cells (PCE = 2.5% for the champion device) by improving all of the figures of merit: the fill factor, open-circuit voltage, and the short-circuit current. The maximum power point tracked efficiency was 2.0%, which is the highest so far reported for this type of solar absorber. The discovery of an efficient HTM for Cs₃Sb₂I₉is an important step in advancing safer lead-free perovskite-inspired solar cells.