Tailoring Exciton Diffusion Length in ZnO@MoS₂ Core–Shell/Polyaniline Nanocomposite Films and Photocurrent Generation Applications

The investigation of excitons in atomically thin MoS2 and its hybrid materials with other semiconductors has gained immense attention, considering its emerging application in light-harvesting systems. However, they suffer from agglomeration while employing on a large scale. To resolve this problem, polymer composites with heterostructures are needed. Designing ternary nanocomposite-based light-harvesting devices is the next step forward for achieving high-performance electron transfer properties. Here, we have synthesized ZnO@MoS2 core–shell heterostructures and modified the surface of the heterostructure with polyaniline (PANI) molecules. In this ternary composite system, PANI is a conducting polymer that constantly transports electrons to the neighboring conduction band of MoS2. A transient photoluminescence study suggests that the rate of exciton decay in the ternary composite system is 6.41 ns at the highest concentration of PANI, which is faster than in bare MoS2. The tuning of exciton diffusion length was also achieved by changing the concentration of PANI, which is a useful parameter for any photodetectors. As a proof of concept, the as-fabricated core–shell heterostructure film integrated with PANI is applied as a photosensitive device and we have observed a nearly 3-fold enhancement of photocurrent under irradiation of visible light, indicating that this type of semiconductor/polymer composite is a very prospective system for future solar light harvesting.