Multiple-optical-modes cross-coupling reduces reflection loss of Ag electrode in organic solar cells by employing the grating-based dielectric1/dielectric2/Ag electrode.

By employing the grating-based dielectric1 (D1)/dielectric2 (D2)/Ag (M) electrode in organic solar cells (OSCs), surface plasmon polariton resonance at the Ag surface, micro-cavity mode in the active layers, and Fabry-Perot cavity mode in the D2 layer cross-couple with each other. This cross-coupling effectively reduces the absorption and reflection losses of ultrathin Ag electrode and enhances the absorption intensity of the OSCs over a wide band from 450 nm to 850 nm. Compared to the OSC with only a planar ultrathin Ag electrode, the short circuit current density (Jsc) and power conversion efficiency (PCE) of the OSC with grating-based D1D2M electrode are increased by 52.13% and 51.51%, respectively. Meanwhile, the OSCs with the grating-based D1/D2/Ag electrode exhibit comparable Jsc and PCE to those of ITO-based OSCs, although the transmittance of the ultrathin Ag electrode is only one-quarter of that of the ITO. This allows the grating-based D1/D2/Ag electrode to have the potential to replace the ITO electrode. Furthermore, the grating structures were made using low-cost and mature digital versatile disc (DVD), which makes the grating-based D1/D2/Ag electrode have a broad application prospect in the large-scale commercial production.