Description:
<jats:sec><jats:label /><jats:p>Perovskite solar cell (PSC) may become the foundation of the photovoltaic industry in the future as it possesses unique photovoltaic properties that are not found in other solar cells. The primary impediment to the commercialization of lead‐based PSC devices is their toxicity and stability. In this scenario, the photovoltaic parameters of a nonpolluting methyl ammonium germanium halide (CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>GeI<jats:sub>3</jats:sub>) PSC device are investigated using numerical modelling. Herein, different hole transport layer materials (HTPLMs) and electron transport layer materials (ETPLMs) are compared for the structure of germanium perovskite photovoltaic cells, and a suitable novel design FTO/SnS<jats:sub>2</jats:sub>/CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>GeI<jats:sub>3</jats:sub>/Zn<jats:sub>3</jats:sub>P<jats:sub>2</jats:sub>/Au is chosen. Evaluating factors like thickness, defect density of the CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>GeI<jats:sub>3</jats:sub>, Zn<jats:sub>3</jats:sub>P<jats:sub>2</jats:sub>, and Zn<jats:sub>3</jats:sub>P<jats:sub>2</jats:sub> layer, interface defect density of HTPLM/perovskite and ETPLM/perovskite, and the consequence of series and shunt resistance are all evaluated, and the optimal value is calculated. The results show that perovskite photovoltaic cells based on the Germanium structure have a power conversion efficiency (PCE) of 25.98%, open‐circuit voltage = 1.26 V, current density = 23.781 mA cm<jats:sup>−2</jats:sup>, and a fill factor of 86.70%. Furthermore, the temperature study analysis shows that the device's PCE decreases to 23.72% at 390 K.</jats:p></jats:sec>