Affordable and sustainable new generation of solar cells: Calcium titanate (CaTiO ₃ ) - Based perovskite solar cells

Indonesia is located along the equator lines with the high intensity of solar radiation averaging about 4.5 kWh of electrical energy/day. This potential leads to the selfsustaining energy possibility fulfilling the electricity needs. Due to their unique electronic structures and high-cost merit over the existing commercial PV technologies, perovskite solar cells (PSCs) have emerged as the next-generation photovoltaic candidate. Their highest power efficiency can be achieved of up to 22.1% in the last 5-6 years. However, this high efficiency came from CH3NH3PbI3 materials which contain lead, a toxic material. Herein calcium titanate (CT) as a lead-free perovskite material were synthesized through sintering of calcium carbonate (CaCO ₃ ) and titanium oxide (TiO ₂ ) by the sol-gel method. CT powders were characterized by SEM, XRF, FTIR and XRD then applied it onto the mesoporous heterojunction PSCs, with a device architecture ITO/TiO ₂ /CaTiO ₃ /C/ITO. By manipulating the raw material stoichiometry and heating temperature in the synthesis of CaTiO3, the device shows the highest power conversion efficiency (PCE) of 2.12%, shortcircuit current density (JSC) of 0.027 mA cm ^-2 , open circuit voltage (VOC) of 0.212 V and fill factor (FF) of 53.90%. This sample can be an alternative way to create lead-free, largescale, and low-cost perovskite solar cells.