Stable MoO_X‐Based Heterocontacts for p‐Type Crystalline Silicon Solar Cells Achieving 20% Efficiency

Abstract Crystalline silicon heterojunction solar cells based on hole‐selective MoO_X contacts provide obvious merits in terms of the decent passivation and carrier selectivity but face the challenge of long‐term stability. With the aim to improve the performance and stability of solar cells with full area MoO_X/metal contacts, a SiO_X tunneling layer on silicon surface is intentionally formed by UV/O₃ treatment and an indium tin oxide (ITO) film is sputtered as a high‐work‐function electrode. Before ITO sputtering, an ultrathin V₂O_X capping layer is introduced to efficiently prevent MoO_X film from air exposure and the damage by sputtering bombardment. The insertion of SiO_X, V₂O_X, and ITO keeps the work function of MoO_X at a high level, which improves the hole selectivity as well as the stability of the contact. The p‐Si/SiO_X/MoO_X/V₂O_X/ITO/Ag solar cell demonstrates an efficiency of 20.0% with improved stability, which is the highest value for MoO_X heterocontacts class on p‐type silicon to date.