In this study, we executed optical simulations to compute the optimum power conversion efficiency (PCE) of a-Si: H/organic photovoltaic (OPV) hybrid tandem solar cell. The maximum ideal short circuit current density (Jsc, max) of the tandem solar cell is initially obtained by optimizing the thickness of the active layer of the OPV subcell for varying thickness of the a-Si: H bottom subcell. To investigate the effect of Haze parameter on the ideal short-circuit current density (Jsc, ideal) of the solar cells, we have varied the haze ratio for the TCO electrode of the a-Si: H subcell in the tandem structure. The haze ratio was obtained for various root mean square (RMS) roughness of the TCO of the front cell. The effect of haze ratio on the Jsc, ideal on the tandem structured solar cell was studied, and the highest Jsc, ideal was obtained at a haze of 55.5% when the thickness of the OPV subcell was 150 nm and that of the a-Si: H subcell was 500 nm. (C) 2017 Elsevier B.V. All rights reserved.