Atomic Interfacial N-Bridging Locks Z-Scheme Charge Transfer in CsPbBr₃@UiO-66-NH₂ Heterojunctions

Area of Science:

• Materials Science
• Nanotechnology
• Photocatalysis

Background:

• Controlling interfacial charge transfer is key for high-efficiency heterojunction photocatalysts.
• Atomic-level modulation strategies for interfaces are scarce, hindering rational design.
• Metal-organic frameworks (MOFs) and perovskites are promising photocatalytic materials.

Purpose of the Study:

• To demonstrate an atomic-scale strategy for creating well-defined heterojunction interfaces.
• To investigate the role of pendant amino groups in forming interfacial bonds and directing charge transfer.
• To enhance photocatalytic activity and charge separation in CsPbBr3-UiO-66-NH2 heterojunctions.

Main Methods:

• Formation of dative coordination bonds (N-bridges) between UiO-66-NH2 and CsPbBr3.
• X-ray photoelectron spectroscopy (XPS) binding-energy shift analysis.
• Density functional theory (DFT) calculations.
• Photoelectrochemical measurements and organic pollutant degradation studies.

Main Results:

• The N-bridge facilitates the preferential exposure of the catalytically active (040) facet of CsPbBr3.
• The N-bridge acts as a directional conduit for interfacial electron transfer, promoting a Z-scheme pathway.
• A significant charge redistribution (approx. 0.80 e-) occurs from MOF to perovskite.
• Photocurrent response increased 3.5-4.0-fold (vs. CsPbBr3) and 2.8-3.3-fold (vs. UiO-66-NH2).
• Efficient degradation of tetracycline and ciprofloxacin was achieved.

Conclusions:

• Interfacial N-bridging is a generalizable atomic-scale paradigm for optimizing charge-transfer kinetics in heterojunction systems.
• This strategy enables rational engineering of interfaces beyond empirical optimization.
• The developed heterojunction exhibits superior photocatalytic performance for environmental remediation.