  We have demonstrated a high-performance low temperature solution processed
electron selective contact consisting of 10 at% antimony doped tin oxide (ATO)
and the neutral polymer polyethylenimine (PEI). Inverted organic photovoltaics
(OPVs) utilizing ATO/PEI as electron selective contact exhibited high power
conversion efficiencies for both the reference P3HT: PCBM and the non-fullerene
based P3HT- IDTBR active layer OPV material systems. Importantly it is shown
that the proposed ATO/PEI carrier selective contact provides light soaking-free
inverted OPVs. Furthermore, by increasing the thickness of ATO layer from 40 to
120 nm the power conversion efficiency of the corresponding inverted OPVs
remain unaffected a parameter which indicates the potential of the proposed
ATO/PEI carrier selective contact for high performance light-soaking-free and
reliable roll-to-roll printing solutions processed inverted OPVs.
