Performance improvement of inverted polymer solar cells with different top electrodes by introducing a MoO3 buffer layer

Molybdenum trioxide (MoO3) was inserted between the active layer and top electrode in inverted polymer solar cells (PSCs) with nanocrystalline titanium dioxide as an electron selective layer. The performances of structurally identical PSCs with different top electrodes (Au, Ag, and Al) were investigated and compared. The interface between MoO3 and different metals was studied by x-ray photoelectron spectroscopy. The results showed that the performances of devices with different metals are greatly improved due to the incorporation of MoO3 and the open-circuit voltage of devices is relatively insensitive to the choice of the anode metal when MoO3 is introduced.