Improving performance and stability of silver bismuth iodide solar cells using carbon nanotubes in the hole transport layer

Silver bismuth iodide (SBI) materials are low-toxic, air-stable, and suitable for replacing lead-based perovskite ones. In this work, the photovoltaic characteristics of SBI-based solar cells with different hole transport layers (HTL) were investigated. Results showed that the power conversion energy (PCE) of Silver bismuth iodide-based solar cells with P3HT as HTL was higher than spiro-OMeTAD. Also, the influence of CNT as a dopant on the performance and stability of the devices was studied. CNT doping of silver bismuth iodide increased the Voc and so the efficiency of the solar cell was enhanced. Furthermore, Also, CNT-doped P3HT improves the interface contact between the active layer and HTL and increases the conductivity of HTL. The best PCE of about 2.16% for devices with FTO/c-TiO2/m-TiO2/silver bismuth iodide-CNT/P3HT-CNT/Au structure was obtained. Moreover, the stability of solar cells under environmental conditions after 30 days was investigated. All devices preserved about 95% of their efficiency.