CsPbBr₃/TiO₂ Heterojunction

Termination controls electron extraction

The interface between CsPbBr₃ and oxide electron transport layers is engineered via surface termination to achieve ideal type-II band alignment and strong built-in fields for efficient charge extraction.

Chenyu, Jiang · Jing, Wang · Wang, Yunpeng · Du, Luchao

Computational Materials Science 2026

Advantages

Efficient charge extraction at SnO₂ interface

The SnO₂/CsPbBr₃ interface exhibits a pronounced interfacial dipole and strong built-in electric field, causing downward band bending and favorable type-II alignment for electron extraction.

Zn-terminated ZnO performs equally well

The Zn-terminated ZnO/CsPbBr₃ interface also shows a pronounced interfacial dipole and strong built-in electric field, resulting in type-II band alignment suitable for electron extraction.

O-terminated ZnO blocks electron injection

The O-terminated ZnO/CsPbBr₃ interface creates an unfavorable energetic barrier that hinders electron injection from CsPbBr₃ into the oxide layer, so this termination should be avoided.

Deep-level defects cause parasitic absorption

Interfacial deep-level defect states induce pronounced sub-bandgap absorption and localized charge accumulation, which may affect device performance and should be suppressed through interface engineering.

Applications

• Perovskite solar cells：Choose SnO₂ or Zn-terminated ZnO as electron transport layer to promote electron extraction from the perovskite layer and reduce interfacial recombination.
• Photodetectors：Apply the interfacial band engineering strategy to optimize carrier separation and collection, improving photodetector response speed and sensitivity.
• Optoelectronic devices：Use the termination-dependent band alignment rules to select appropriate ETL materials and interface configurations for various optoelectronic devices.
• 2D material heterojunctions：Extend the atomistic characterization and computational approaches for CsPbBr₃/oxide interfaces to the design of other 2D material heterojunctions.