Synergistic effects of dual-optical-nanocavity resonance and localized surface plasmons to enhance light absorption in organic solar cells

Abstract

For organic solar cells, it is a vital issue to effectively confine more light in a thin photoactive layer to guarantee both efficient light absorption and effective collection for photogenerated carriers. Herein, a simple but high-performance composite structure consisting of a front indium tin oxide hemisphere (ITO-HS) array and a silver nanodisk (Ag-ND) array embedded in the photoactive layer is proposed. Benefiting from antireflection and light scattering induced by the ITO-HS array, dual-optical-nanocavity resonances formed by the ITO-HS array, Ag-ND array and Ag electrode, together with the secondary scattering and localized surface plasmons caused by the Ag-ND array, significantly enhanced light absorption can be achieved in a broad range from 300 to 800 nm. Simulation results indicate that the short-circuit current density and power conversion efficiency can be remarkably enhanced by 43.58% and 46.03%, respectively, through introducing the optimal composite light management structure into the normal inverted device architecture of ITO/ZnO/PTB7:PC 71 BM (100 nm)/MoO 3 /Ag, as compared to the control device. Furthermore, this composite light management structure exhibits excellent omnidirectional light confinement. Considering the notable device performance enhancement and the simple structure, this study may provide a guideline for designing and fabricating high-performance light management structures applicable in thin film-based optoelectronic devices. • A simple and efficient light management structure consisting of a front ITO-HS array and an Ag-ND array is proposed. • The enhancement of 43.58% and 46.03% for J sc and PCE is achieved for the device with the optimized light management structure. • Excellent omnidirectional light management is delivered for the proposed optical structure.