Short-chain ligands capped CuInSe2 quantum dots as hole transport material for inverted perovskite solar cells

Abstract In this paper, oleylamine capped CuInSe2 (OAm-CISe) quantum dots (QDs) were synthesized with a modified hot injection method. The organic long-chain ligands attached on the surface of quantum dots have insulating properties, which affects the charge transport between the quantum dots. Thus the long-chain ligand on OAm-CISe surface was replaced by a short-chain ligand of 3-mercaptopropionic acid (MPA) by phase transfer strategy. The MPA capped CISe (MPA-CISe) was applied as hole transport material to fabricated inverted perovskite solar cells (PSCs). The power conversion efficiency (PCE) of PSCs based on MPA-CISe increased to 8.59% from 7.18% for the PSCs based on OAm-CISe (7.18%). The experimental results indicate that the PCE increase could be due to higher light transmission rate and conductivity of MPA-CISe film than the OAm-CISe film.