Impact of carbon electrode layer on the series resistance and fill factor of CH₃NH₃PbI₃ perovskite solar cell

Methylammonium lead triiodide (CH 3 NH 3 PbI 3 ) is a metal halide perovskite that is attracting great attention owing to its remarkable optoelectronic properties especially in perovskite solar cells (PSCs) and perovskite light-emitting devices (PLEDs). In this work, the impact of the number of carbon electrode layers on the photovoltaic parameters and impedance spectra of hole transport material-free (HTM-free) glass/FTO/c-TiO 2 /m-TiO 2 /m-ZrO 2 /carbon monolithic PSCs is examined. A significant influence of the carbon electrode layers on the fill factor and series resistance is revealed. The optimum values of fill factor and series resistance are observed when a 3-layered carbon electron is used in the PSC. This is due to higher charge transportation, higher electrical conductivity, higher electron mobility, and lower recombination losses.