High-efficiency perovskite solar cells improved with low-cost orthorhombic Cu2Znsns4 as the hole-transporting layer

Abstract

Quaternary copper chalcogenide Cu2ZnSnS4 (CZTS) nanoparticles (NPs) were synthesized with the sol-gel technique and used as the hole-transporting layer (HTL), achieving a power-conversion efficiency (PCE) of 13.41 %, which is the highest PCE for Cu-based inorganic HTLs. The effects of the CZTS HTL on the optical absorption, crystallinity, crystal plane orientation and hysteresis of the J-V curve for the devices with a perovskite film were investigated and compared with spiro-OMeTAD, revealing the role of CZTS in efficient hole transporting in perovskite solar cells. In addition to the traditional use of the light absorber, this study reveals a new role of CZTS in photovoltaics, acting as an HTL, providing a completely different insight into the CZTS development.