MoO3 as a Cathode Buffer Layer Material for the Improvement of Planar pn-Heterojunction Organic Solar Cell Performance

The use of MoO 3 as a cathode buffer layer inserted between LiF and Al improved the power conversion efficiency (PCE) of planar pn-heterojunction organic solar cells (OSCs) by reducing exciton quenching at the interface between the n-type organic active layer and the electrode. The cell using an amorphous molecular material, tris[4-(5-phenylthiophen-2-yl)phenyl]amine, as a p-type organic semiconductor, C 70 as an n-type organic semiconductor and MoO 3 as a cathode buffer layer exhibited a PCE of 3.3% under AM1.5G illumination (100 mW cm -2 ), which is of the highest level among those for planar pn-heterojunction OSCs using amorphous molecular materials as donor materials.