Engineering the Interface of Cu/MoS₂ Nanostructures for Improved Charge Transfer for Applications as PEC Anode Materials

Abstract

Electronic structures of metal and semiconductor composites play a crucial role in photoelectric conversion. To obtain a fast-response photoelectrochemical (PEC) anode, its orbital regulation is a challenge. Herein, the occupancy state of the d orbitals of Mo is adjusted to achieve high-efficiency photoelectric conversion by adjusting the quantity of Cu by magnetron sputtering deposited in Cu/MoS2 composites. Characterization results indicate that the SEM morphology of MoS2 changes distinctly. Meanwhile, the (111) and (200) diffraction peaks and 0 and 2+ valence states of Cu appeared in XRD and XPS, respectively, confirming the successful synthesis of Cu/MoS2. The prior band shift at the heterojunction causes efficient separation of photogenerated charge carriers and the shift of the position of Mo 3d to higher binding energies, which results in weaker intrinsic luminescence at 810 nm in the PL spectrum and smaller charge transfer resistance in the electrochemical impedance spectroscopy spectra, confirming the high PEC performance of the Cu/MoS2 composites. Meanwhile, the density functional theory calculations reveal that the energy of the d orbital of Mo in MoS2 decreases, which is helpful to accept electrons in Cu 3d. The Mo d track-occupancy introduced through the strong interplay between the most desirable combination of MoS2 and Cu will be accountable for such record-high performance. Therefore, this study makes a strong case for fine-tuning the electronic structures of PEC anode materials.

Defect and interface/surface engineering synergistically modulated electron transfer and nonlinear absorption properties in MoX2 (X = Se, S, Te)@ZnO heterojunction

“…To verify the role of vacancy defects in the interfacial charge transfer of MoX 2 and MoX 2 @ZnO, models of the energy band, density of states and electron density of MoX 2 and MoX 2 @ZnO in different states were constructed based on first principles. 57,58 Fig. S3(a) † shows the MoX 2 atomic structure model without vacancy defects, in which the calculated band gaps of MoSe 2 and MoS 2 are 0.84 eV and 0.72 eV, respectively, both of which are smaller than the true bandgap values of TMDs (Fig.…”

“…According to their structural compatibility and van der Waals interaction, 2D MX 2 layers can be fabricated into a variety of transverse and longitudinal heterostructures, 20 where the creation of a heterojunction is an effective means to the improve semiconductor performance of materials. Thus far, various heterojunction composites based on modified TMDs have been reported, including metal@TMDs (Ag, Cu, Au), [21][22][23] metallic-compound@TMD composites (CuO, ZnO, Co 3 O 4 , TiO 2 ), [24][25][26][27][28][29] nonmetal@TMDs (graphene) 30 and TMD@TMD composites (MoS 2 , WSe 2 ). 31,32 Among them, combining TMDs with metallic compounds to construct heterojunctions has become a popular method to change their structure and performance defects.…”

Photogenerated Carrier Separation and Localized Surface Plasmon Resonance in MoS2/Metal Nanocomposites: Implications for Photoelectric Devices

“…Eventually, due to mutual compression, a significant number of these MoS 2 nanosheets bent and self-assembled, ultimately leading to the formation of complete 3D MoS 2 nanoflowers. 37 Parts b, e, h, and k of Figure 1 display the SEM images of MoS 2 , MoS 2 / Ag10, MoS 2 /Ag45, and MoS 2 /Cu10, respectively. The SEM images reveal that Ag NPs and Cu NPs are dispersed on the surface of MoS 2 when the sputtering condition is 10 min.…”

“…Later, the MoS 2 NPs agglomerated to form large clusters, which then grew along the (002) crystal direction, resulting in the formation of typical MoS 2 nanosheets. Eventually, due to mutual compression, a significant number of these MoS 2 nanosheets bent and self-assembled, ultimately leading to the formation of complete 3D MoS 2 nanoflowers . Parts b, e, h, and k of Figure display the SEM images of MoS 2 , MoS 2 /Ag10, MoS 2 /Ag45, and MoS 2 /Cu10, respectively.…”