Highlights• MoOx is used to replace p-a-Si:H at the hole contactin silicon heterojunction (SHJ) solar cells, leading to a reduction of parasitic absorption and a JSC improvement on average of 0.5 mA/cm 2 .• Influence of MoOx thickness and annealing condition on the SHJ cell performance was studied and optimal parameters were determined.• Impact of MoOx thickness and anneal treatment on the thin film interfaces at the hole contact was investigated and an interfacial dipole in the form of a-SiOx was postulated.• A glass to glass 1-cell mini-module was fabricated using a MoOx-contacted SHJ cell.• After damp-heat testing, good long-term stability was achieved at module-level, with a degradation of less than 3%abs (passing the IEC61215 standard).