High-Performance p–n Junction Transition Metal Dichalcogenide Photovoltaic Cells Enabled by MoOx Doping and Passivation

Layered semiconducting transition metal dichalcogenides (TMDs) are promising materials for high-specific-power photovoltaics due to their excellent optoelectronic properties. However, in practice, contacts to TMDs have poor charge carrier selectivity, while imperfect surfaces cause recombination, leading to a low open-circuit voltage ( V OC ) and therefore limited power conversion efficiency (PCE) in TMD photovoltaics. Here, we simultaneously address these fundamental issues with a simple MoO x ( x ≈ 3) surface charge-transfer doping and passivation method, applying it to multilayer tungsten disulfide (WS 2 ) Schottky-junction solar cells with initially near-zero V OC . Doping and passivation turn these into lateral p–n junction photovoltaic cells with a record V OC of 681 mV under AM 1.5G illumination, the highest among all p–n junction TMD solar cells with a practical design. The enhanced V OC also leads to record PCE in ultrathin (<90 nm) WS 2 photovoltaics. This easily scalable doping and passivation scheme is expected to enable further advances in TMD electronics and optoelectronics.