The computational modelling of a novel photovoltaic cell has showed an enhancement in the empirically validated efficiency of a-Si:H based solar cells. To model and optimize the functionality of the suggested cell, different absorber layer and buffer layer thicknesses are used. The working temperature and illumination is optimized. A key element in enhancing the performance of any photovoltaic device is bandgap grading. Here, the bandgap of the p-type absorber layer is linearly graded. Bulk defects are also added to replicate the optimal structure. Through simulation, the results in Voc, Jsc, fill factor, and efficiency of the suggested cell is examined. From 11.62 % to 42.22 %, the optimized cell's efficiency shows a significant rise. The reference model (p-i-n a-Si:H), a-Si:H/CdS, a-Si:H/SnS/CdS, and aSi:H/SnS/CdS/ZnS (proposed model) are four architectures that are investigated and contrasted. The one with the highest efficiency is a-Si:H/SnS/CdS/ZnS. The SCAPS - 1D solar simulator is used to simulate the project.