Photocatalytic Mechanisms in Semiconductor Systems

Photocatalysis in semiconductor systems harnesses light energy to drive chemical transformations via photo-generated charge carriers. Absorption of photons with energy exceeding the material’s band gap generates electrons and holes, which must be efficiently separated and transferred to surface active sites to initiate redox reactions. Control of band structure, heterojunctions and internal or external electric fields is central to minimising charge recombination and maximising activity. Recent advances in operando and in situ characterisation have illuminated dynamic carrier behaviour, revealing how facet engineering, defect distribution and field-induced charge steering underpin performance. These insights are accelerating the rational design of robust photocatalysts for applications in environmental remediation, solar fuel generation and CO₂ reduction.

Research from Nature Portfolio

Recent studies have demonstrated the role of surface electric fields in directing photocatalytic reactions. Rationally designed organic nanocrystals generate a photo-induced outer electric field at their surfaces, driving long-range electrophoresis and enhancing solid–solid interactions that accelerate microplastic decomposition. Operando analyses and theoretical modelling reveal how surface charge anisotropy controls the direction and intensity of this field. Complementarily, investigations of BiOBr facet junctions have uncovered contiguous internal electric fields that steer photoexcited electrons along defined pathways. Quantitative models based on diffusion length and drift distance enable precise tuning of platelet dimensions to maximise charge separation efficiency and catalytic performance.

Photocatalytic Mechanisms in Semiconductor Systems publication trend

The graph below shows the total number of articles in photocatalytic mechanisms in semiconductor systems across all publications each year (not limited to Nature Index journals).

Technical terms

Band gap: energy difference between the valence band maximum and the conduction band minimum in a semiconductor, dictating light absorption threshold.

Charge separation: spatial separation of photo-generated electrons and holes to prevent recombination and enable redox reactions.

Built-in electric field (IEF): internal electric field within a semiconductor or at heterojunctions that drives the directional movement of charge carriers.

Photo-generated outer electric field (OEF): electric field established at the surface of a photocatalyst under illumination, influencing particle motion and interfacial reactions.

Operando characterisation: real-time analysis of materials under operational conditions to monitor structural, electronic and chemical changes during catalysis.

References

1. Photogenerated outer electric field induced electrophoresis of organic nanocrystals for effective solid-solid photocatalysis. Nature Communications (2024).
2. Unveiling the charge transfer dynamics steered by built-in electric fields in BiOBr photocatalysts. Nature Communications (2022).
3. Nanometer-Resolved Operando Photo-Response of Faceted BiVO4 Semiconductor Nanoparticles. Journal of the American Chemical Society (2024).
4. In Situ Characterization Techniques Applied in Photocatalysis: A Review. Advanced Materials Interfaces (2022).
5. Heterogeneous photocatalysts: an overview of classic and modern approaches for optical, electronic, and charge dynamics evaluation. Chemical Society Reviews (2019).