Photoinduced ultrafast charge transfer and enhanced optoelectronics in MoS2/Ti2CO2 van der Waals heterojunction

The rapid development of two-dimensional van der Waals heterostructures has sparked notable interest in optoelectronic applications. However, issues such as lattice mismatch or a misalignment of the constituent layers can drastically suppress charge transfer for these interlayer transitions. Here, we construct a new type-II MoS2/Ti2CO2 heterojunction using density functional theory and non-adiabatic molecular dynamics simulations, revealing the optimal band alignments across various stacking configurations. The optimized heterointerface exhibits ultrafast charge separation, with electron and hole transfer completing within 4.6 fs and 228.8 fs, respectively, and a prolonged carrier lifetime of 1.53 ns. Compared to pristine monolayers, the heterointerface displays broader light absorption from the visible to the UV spectrum. This optoelectronic performance is further enhanced by biaxial strain, which effectively tunes the photoresponse, resulting in a high theoretical power conversion efficiency of 12.89%. These findings offer valuable guidance for designing high-performance MoS2-based heterostructures for next-generation optoelectronic and energy conversion devices.