Optimized photoelectric conversion properties of PbS x Se1−x -QD/MoS2-NT 0D–1D mixed-dimensional van der Waals heterostructures

Abstract

Zero-dimensional (0D)–one-dimensional (1D) mixed-dimensional van der Waals (MvdW) heterostructures have shown great potential in electronic/optoelectronic applications. However, addressing the interface barrier modulation and charge-transfer mechanisms remain challenging. Here, we develop an analytic model to illustrate the open-circuit voltage and charge-transfer state energy in PbS x Se1−x -quantum dots (QDs)/MoS2-nanotube (NT) 0D–1D MvdW heterostructures based on atomic-bond-relaxation approach, Marcus theory and modified-detailed balance principle. We find that the band alignment of PbS x Se1−x -QDs/MoS2-NT heterostructures undergoes a transition from type II to type I, and the threshold of size is around 5.6 nm for x = 1, which makes the system suitable for various devices including photocatalytic device, light-emission device and solar cell under different sizes. Our results not only clarify the underlying mechanism of interfacial charge-transfer in the heterostructures, but also provide unique insight and new strategy for designing multifunctional and high-performance 0D–1D MvdW heterostructure devices.