Light trapping of organic solar cells by nanotextured surfaces

This work proposes hybrid antireflection (AR) structure that integrates moth eye texturing and multi-layer interference coating for application to organic solar cells (OSCs). We conduct nearly global optimization of the geometric parameters (i.e., the period and height of moth eye array and the thicknesses of interference layers) for the hybrid AR system. In the optimization algorithm, the simple grid search method is combined with the Hooke and Jeeves pattern search method to accelerate the search process. By using optical simulations based on the finite-difference time-domain method, we show that the proposed AR system can enhance the short-circuit current density of P3HT:PCBM-based OSCs by around 10%. The design concept of hybrid AR structure is useful for broadband light trapping of OSCs.