Multiscale hierarchically wrinkled MoS₂ nanosheet films with enhanced photoelectrochemical properties

Two-dimensional (2D) molybdenum disulfide (MoS₂) has shown promise for optoelectronic and photoelectrochemical (PEC) applications, yet achieving a balance between light absorption and charge transport within the MoS₂ layer, as well as developing a facile strategy for scalable production, remains challenging. Here, we report a scalable, solution-based approach that overcomes these limitations through hierarchical structuring of MoS₂ nanosheets. The multiscale hierarchical wrinkles in the resulting MoS₂ nanosheet film enhance broadband light absorption through increased optical path length and geometry-induced field enhancement, increase the electrochemically active surface area, and introduce localized bandgap gradients that promote separation and extraction of photogenerated carriers compared with the flat film. Significantly, incorporating hierarchically wrinkled MoS₂ as an ultrathin (∼50 nm) water-splitting photoanode with a TiO₂ protective layer and a CoFeO_xH_y oxygen evolution reaction co-catalyst layer yields an 8.4-fold increase in photocurrent density and a 430 mV reduction in onset potential relative to flat controls, while achieving long-term operational stability with 93.8% current retention over 10 h.