The performance enhancement of HTM-free ZnO nanowire-based perovskite solar cells via low-temperature TiCl_4 treatment

摘要

Charge carrier transport layer made of aligned ZnO nanowires (NW) coated with TiO2layer via low-temperature hydrolysis process for perovskite solar cells (PSC) applications. Aligned ZnO NWs were grown by solution approach onto transparent conducting oxide substrates and treated with 25 mM of titanium tetrachloride (TiCl4). TiO2layered ZnO NWs were composed of single crystalline, uniformly covered with amorphous TiO2nanoparticles was characterized by scanning and transmission electron microscopy. Such TiO2layered ZnO NW architecture, with the unique combination of high surface-area and infiltration of perovskite more into the electrode and a maximum photocurrent density (JSC) of 14.30 mA cm−2and a power conversion efficiency (η) of 7.05% are demonstrated, which is higher than the ZnO NWs. Dark current density is decreased for TiO2layered ZnO NW-based PSCs, due to the good interface formation between the electrode/sensitizer and it has higher energy barrier to overcome required high onset potential. TiO2layered ZnO NWs architecture opens up a novel configuration for high-performance optoelectronic devices.