We demonstrate enhanced performance of nanopatterned P3HT:PCBM blend organic photovoltaics fabricated using the Pattern Replication In Non-wetting Templates (PRINT) technique. Enhanced cell performance is demonstrated in four ways. First, optical modeling and photonic band structure calculations are performed using the scattering matrix formulation. These simulations require optical constants of each layer in the cell that are measured using spectroscopic ellipsometry. Optical enhancements occur due to multiple effects including the excitation of quasiguided modes within the nanopatterned layer. Second, simulations are verified over a range of incident angles due to the strong angular dependence of trapped optical modes. Third, simulations of electron/hole transport in the device are conducted thereby anticipating how much of the overall cell improvement is due to optical effects and how much is due to transport processes. Finally, we have patterned a photoactive layer (P3HT-PCBM) with features on a 200 nm scale and will experimentally contrast the relative performance of patterned and unpatterned devices.