Abstract In this article, we have studied an identical section of a core-shell ZnO Nanorod (NR) based lead-free perovskite solar cell. Various factors affecting the solar cell’s performance have been rigorously investigated for device optimization; specifically, the length and diameter of the ZnO NR core, perovskite shell thickness, thickness of perovskite cap layer, and hole transport layer (HTL) thickness. The defect density of states (DOS) in the perovskite absorber layer and the effect of interface defect density on the performance of the cell are also studied. We obtained power conversion efficiency (PCE) of 14.50%, the open-circuit voltage (VOC) of 0.96 V; short-circuit current density (JSC) of 18.11 mA/cm2 and Fill factor (FF) of 83.35%. We also analyzed the effect of tilt or inclination of NR on the performance of the cell which is a crucial factor toward achieving high performance. By optimizing the device parameters, we have achieved a PCE of 21.27%, VOC of 0.97 V, JSC of 29.56 mA/cm2, and FF of 84.15% at an inclination of 10-degree tilt with respect to the incident light under AM 1.5 illumination. The shadowing mechanism behind efficiency droop is also presented to further realize an optimal design high-performance PSC.