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The need to increase transparency in existing passivating contacts for crystalline silicon solar cells has motivated the development of transparent contacts based on transition metal oxides (TMOs). Among hole‐selective materials, molybdenum oxide (MoOx) has achieved the greatest success so far. However, despite providing low contact resistivity, MoOx relies on an intrinsic hydrogenated amorphous silicon (a‐Si:H(i)) interlayer to achieve high levels of surface passivation and thus high open‐circuit voltage at a device level, partially defeating the objective of improved transparency. Herein, we report unprecedented performance for a‐Si:H‐free MoOx‐based contacts by employing an alternative passivating interlayer based on a well‐engineered chlorine‐containing Al‐alloyed titanium oxide/titanium dioxide (AlyTiOx/TiO2)stack. The resulting AlyTiOx/TiO2/MoOx stack achieved record levels of passivation, reaching J0 values as low as 16 fA cm−2, closer to values reported for a‐Si:H‐based contacts, while maintaining lower contact resistivity, well below 100 mΩ cm−2. Additionally, the stack presents improved transparency compared to a‐Si:H‐based contacts, with gains in short‐circuit current density of at least 0.8 mA cm−2. The work pushes the performance of hole‐selective passivating contacts based on TMOs to new levels, enabling a record efficiency of 22.53% for cells with fully transparent hole‐selective passivating contacts. This work serves as an important stepping stone toward low‐thermal‐budget, simple manufacturing of high‐efficiency solar cells. [ABSTRACT FROM AUTHOR]

Passivating contact technologies are essential for fabricating high‐efficiency crystalline silicon (c‐Si) solar cells, and their application and incorporation into manufacturing lines has ranked as a hot topic of research. Generally, ideal passivating contacts should combine excellent electrical contact, outstanding surface passivation, and high optical transparency. However, addressing all these criteria concurrently is challenging since it is unlikely for any single material to exhibit both efficient carrier transport and surface‐defect passivation while demonstrating negligible parasitic absorption. In this work, several earth‐abundant, wide‐bandgap materials are combined to engineer high‐quality transparent electron‐selective passivating contact structures capable of overcoming these obstacles. A highly transparent AlyTiOx/ZnO/TiO2 stack with a total thickness of 3 nm, prepared by atomic layer deposition, is shown to provide a close‐to‐ideal passivating contact to Si surfaces by enabling dual functions of remarkable silicon surface passivation (with an effective minority carrier lifetime of 12.3 ms, an implied open‐circuit voltage of 730 mV, and a surface recombination current density prefactor of 2.6 fA cm−2), combined with efficient carrier transport with a very low contact resistivity of 3.4 mΩ cm2. These results demonstrate that low‐cost silicon interface‐engineering strategiesbased on transition metal oxides can push c‐Si solar cell performance to its theoretical limits. [ABSTRACT FROM AUTHOR]