Anti-reflection metallic anode-enhanced performance of organic solar cells via cross coupling between Fabry–Perot cavity modes and microcavity modes

Abstract

An effective anti-reflection metallic anode with the structure of glass/dielectric2 /Ag (D1D2M) is demonstrated both in small-molecule (SM) and conjugated polymer (CP) organic solar cells (OSCs). The anti-reflection mechanism is investigated by the finite-difference time-domain numerical calculation method and the experimental method. By tuning the refractive index and the thickness of the D2 layer, the reflection light is confined in the Fabry–Perot (F-P) cavity modes, which effectively enhances the transmittance of the D1D2M anode in the wavelength range of 420 nm–800 nm. Compared with the conventional glass/Ag (D1M) anode, the experimental transmittance of the D1D2M anode is enhanced by 33.24% at a wavelength of 550 nm. By replacing the D1M anode with the D1D2M anode in the OSCs, the F-P cavity modes cross couple with the microcavity modes in the active layers. As a result, the absorption intensity is obviously increasing in a wide angle range ( 0 ≤ θ ≤ 85 ∘ ) in the wavelength ranges of 475 nm–650 nm and 540 nm–720 nm for the SM and CP OSCs, respectively. The short circuit current density and power conversion efficiency of the SM OSC is increased by 25.07% and 27.23%, respectively.