Cell parameter shift over 20 consecutive reverse bias cycles. With the efficiency η, the fill factor FF, the parallel resistance R_p and the reverse current-density j_rev at a reverse bias of V_rev = -12 V. The HIP-MWT+ cell that uses the AlO_X is significantly affected by the reverse bias. The increase in reverse current–density goes hand in hand with the deterioration of R_p which has the negative impact on the FF.