Stability study in organic solar cells based on PTB7:PC 71 BM and the scaling effect of the active layer

•Devices using PTB7:PC71BM blend and an alternative top electrode are fabricated.•Performance and stability is studied as a function of the active area.•Environmental stability in presence of light, remains independent of active area.•Environmental stability in absence of light is enhanced for scaled devices.•Lifetime in our OPVs is determined mainly by intrinsic active layer instabilities.