Comprehensive method for analyzing the power conversion efficiency of organic solar cells under different spectral irradiances considering both photonic and electrical characteristics

•Method to analyze power-conversion efficiency under various solar irradiance.•Power-conversion efficiency at local irradiance is 5.4% higher than AM1.5G.•Diffuse local irradiance has gain of 23.7–27.9% relative to AM1.5G conditions.•Annual average energy density yield is estimated as 31.89kWh/m2 in Malaysia.