MoS₂-Scaffolded CsPbBr₃Hybrids: In Situ Synthesis and Interfacial Charge Transfer Dynamics

The integration of two-dimensional transition metal dichalcogenides with halide perovskites offers a promising approach to tailoring interfacial charge transfer for optoelectronic and energy applications. MoS₂-scaffolded CsPbBr₃ hybrids were synthesized via in situ hot-injection, where PbBr₂ directed CsPbBr₃ nucleation upon Cs-oleate injection, enabling nanocrystals to grow directly on the exfoliated MoS₂ layers and promoting quasi-type-II heterojunctions. Unlike physical mixing, which showed negligible interaction, in situ incorporation led to strong photoluminescence quenching and efficient charge transfer. XRD, FESEM, and TEM spectroscopy confirmed the coexistence of CsPbBr₃ and MoS₂ phases and embedded nanocrystals. Femtosecond transient absorption (fs-TA) spectroscopy revealed ultrafast charge transfer in the hybrids, with a fast component lifetime (τ₁) decreasing from 14.77 ps in pristine CsPbBr₃ to 8.50 ps in CsPbBr₃@1T/2H-MoS₂, corresponding to an electron transfer rate of 4.99 × 10¹⁰ s^–1; notably, a slower decay component (τ₂ = 47.90 ps) appeared only in the hybrids, reflecting interfacial electron relaxation and efficient carrier separation. Electrochemical studies demonstrated enhanced interfacial charge transport and low resistance, confirming effective electronic coupling. DFT calculations indicated stronger PbBr₂–MoS₂ interactions (−26.8 kcal/cell) than CsBr-terminated surfaces (−24.1 kcal/cell), favoring uniform nucleation and intimate interfaces. Together, these results highlight the critical role of in situ interfacial engineering in achieving high-performance CsPbBr₃/MoS₂ heterostructures.