Ultrafast Charge Transfer and Delayed Recombination in MoSe/P3HT van der Waals Heterostructures.

Two-dimensional materials possess exceptional optoelectronic properties, including high carrier mobility and tunable bandgaps, making them highly suitable for various electronic and optoelectronic applications. While inorganic 2D materials exhibit ultrafast and efficient interlayer charge transport, they suffer from limited light absorption capabilities. In contrast, organic semiconductors offer broad spectral absorption but are constrained by their inherently low charge carrier mobility. Conjugated polymers such as poly(3-hexylthiophene) (P3HT) exhibit excellent mechanical flexibility, solution processability, and film-forming capabilities, enabling the scalable fabrication of high-performance flexible optoelectronic devices. To overcome these limitations, we successfully developed a type-II MoSe/P3HT heterostructure (HS) that combines the complementary advantages of both material systems. Steady-state absorption measurements reveal that the MoSe/P3HT HS exhibits both broader spectral coverage and stronger absorption intensity compared with its individual components. Photoluminescence (PL) spectroscopy studies demonstrate significant PL quenching in the HS, suggesting efficient interfacial charge transfer between the constituent layers. Transient absorption spectroscopic results reveal efficient interfacial hole transfer from MoSe to P3HT with a time scale of 19.9 ps. Notably, the MoSe/P3HT heterostructure exhibits an exceptionally slow charge recombination lifetime of 901.4 ps, significantly surpassing that of inorganic-inorganic van der Waals heterostructures. Organic-inorganic hybrids demonstrate enhanced light absorption, ultrafast charge transfer, and prolonged carrier lifetimes, rendering them highly promising for high-efficiency photovoltaics, broadband photodetectors, and other advanced optoelectronic applications in the future.