Anti-reflection metallic anode-enhanced performance of organic solar cells via cross coupling between Fabry-Perot...

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.