10 cm2 nonfullerene solar cells with efficiency over 10% using HxMoO3-assisted growth of silver electrodes with a low threshold thickness of 4 nm†
In this study, we report 10 cm2 nonfullerene solar cells with power conversion efficiency of 10.24%. The demonstration of the large-area cells is based on the HxMoO3-assisted growth of two silver electrodes, namely, the ultrathin-transparent electrode (on the top) and opaque electrode (at the bottom). The device structure has the configuration glass/HxMoO3/opaque Ag (70 nm)/active layer/HxMoO3/ultrathin Ag (8 nm)/MoO3. The chemically reactive HxMoO3 could react with silver oxide during the growth of the initial few nanometers of silver, as inferred from X-ray spectroscopy measurements. The reaction increases the nucleus sites that assist the continuous and uniform growth of the silver films. The percolation threshold thickness of conductive ultrathin Ag films on HxMoO3 can be as low as 4 nm. The root-mean-square surface roughness of opaque silver (70 nm) grown on the HxMoO3 surface is as low as 1.06 nm. HxMoO3 facilitates the growth of uniform, continuous and smooth silver films that enable the efficient large-area nonfullerene organic solar cells.