Mixed-dimensional van der Waals nanohybrids (MvNHs) of two-dimensional transition-metal dichalcogenides (TMDs) and zero-dimensional perovskites are highly promising candidates for high-performance photonic device applications. However, the growth of perovskites over the surface of TMDs has been a challenging task due to the distinguishable surface chemistry of these two different classes of materials. Here, we demonstrate a synthetic route for the design of MoSe2–CsPbBr3 MvNHs using a bifunctional ligand, i.e., 4-aminothiophenol. Close contact between these two materials is established via a bridge that leads to the formation of a donor–bridge–acceptor system. The presence of the small conjugated ligand facilitates faster charge diffusion across MoSe2–CsPbBr3 interfaces. Density functional theory calculations confirm the type-II band alignment of the constituents within the MvNHs. The MoSe2–CsPbBr3 nanohybrids show much higher photocurrent (∼2 × 104-fold photo-to-dark current ratio) as compared to both pure CsPbBr3 nanocrystals and pristine MoSe2 nanosheets owing to the synergistic effect of pronounced light–matter interactions followed by efficient charge separation and transportation. This study suggests the use of a bifunctional ligand to construct a nanohybrid system to tune the optoelectronic properties for potential applications in photovoltaic devices.

Heterostructures based on atomically thin twodimensional layered transition metal dichalcogenides are highly promising for optoelectronic device applications owing to their tunable optical and electronic properties. However, the synthesis of heterostructures with desired materials having proper interfacial contacts has been a challenging task. Here, we develop a colloidal synthetic route for the design of MoSe 2 −Cu 2 S nanoheterostructures, where the Cu 2 S islands grow vertically on top of the defect sites present on the MoSe 2 surface, thereby forming a vertical p−n junction having plasmonic characteristics. These MoSe 2 − Cu 2 S nanoheterostructures are used to fabricate photodetectors with superior photoresponse characteristics. The fabricated device exhibits a broad-band spectral photoresponse over the visible to near-infrared range with a peak responsivity of 410 mA W −1 at −2.0 V and over 3000-fold photo-to-dark current ratio. The superior device performance of MoSe 2 −Cu 2 S over only MoSe 2 devices is due to the combined effect of the formation of the p−n junction, pronounced light−matter interactions, and passivation of surface defects. This study would pave the way for designing a new class of nanoheterostructured materials for their potential applications in next-generation photonic devices.

The electrocatalytic water splitting activity of layered transition metal dichalcogenides (TMDs) is limited by inert basal planes and slower reaction kinetics. Here, we demonstrate the use of MoSe2–Cu2S nanoheterostructures (NHSs)...

We show that the colloidal growth of SnS nanosheets (NS), a group IV metal chalcogenide (MC), on MoSe2 NS, a transition metal dichalcogenide (TMDC), results in the formation of type-II nanoheterostructures (NHS). The MoSe2/SnS NHS synthesis is accompanied by in situ generation of MoO3–x at the MoSe2 and SnS interface activating the otherwise electrochemically inert basal planes of MoSe2 NS. The MoSe2/SnS NHS exhibit more active sites, and the built-in electric field at the interface enhances the rate of charge transfer. The largely enhanced electrocatalytic activities are attributed to the electronic property manipulation due to the synergistic interactions between MoSe2 NS and SnS NS. This work provides insights into the design of multicomponent low-dimensional 2D/2D (D = dimension) NHS based on TMDC/MC combination with enhanced electrochemical properties, in particular for applications of water splitting.

Two-dimensional (2D) MoSe 2 −Cu 2−x S nanocomposite-based heterojunction two color-band photodetectors on ntype GaAs have been fabricated and are reported for the first time. MoSe 2 −Cu 2−x S nanocomposites were synthesized using a colloidal route, where defect sites present on solution-processed MoSe 2 nanosheets act as nucleation centers for the vertical growth of Cu 2−x S islands with plasmonic characteristics. High-resolution transmission electron microscopy studies confirmed the formation of the djurleite phase (Cu 1.97 S) of Cu 2−x S along with Cu 2 S nanoparticles which exhibit the localized surface plasmon resonance (LSPR) in the near-infrared (NIR) wavelength range due to the availability of free holes. The device with the MoSe 2 − Cu 2−x S/GaAs heterojunction exhibited a broad response in the visible region as well as in the NIR region, depicting a multispectral photoresponse, whereas the one with the MoSe 2 /GaAs heterojunction exhibited a photoresponse only in the visible region. Also, the photo-to-dark current ratio of the MoSe 2 −Cu 2−x S heterojunction device is observed to be 1.1 × 10 5 as compared to 1.0 × 10 3 for the device with MoSe 2 only. Both the devices depicted peak responsivity and detectivity at a wavelength of 630 nm without any applied bias, exhibiting the operation of the device as a self-powered photodetector. However, the MoSe 2 −Cu 2−x S/GaAs heterojunction device showed enhanced responsivity and detectivity in the NIR wavelength region as compared to that of the MoSe 2 /GaAs heterojunction due to plasmonic absorption by Cu 2−x S nanoparticles. These results enlighten the importance of designing nanoheterostructures using a plasmonic material for heterojunction optoelectronic devices.