Semitransparent and flexible perovskite solar cell with high visible transmittance based on ultrathin metallic electrodes.

We have fabricated semitransparent and flexible indium-free perovskite solar cells (PeSCs) with high visible transmittance employing two kinds of composite ultrathin metallic electrodes, MoO/Au and MoO/Au/Ag/MoO/Alq, as the bottom and top electrodes, respectively. These electrodes show superb electrical conductivity, excellent mechanical robustness, and high optical transparency which are quite suitable for semitransparent and flexible PeSCs. An overall power conversion efficiency (PCE) of 6.96% and an average visible transmittance of 18.16% in the wavelength range of 380-790 nm were achieved. Furthermore, the devices maintained 71% of their initial PCE after 1000 bending cycles with a bending radius of 4 mm.