Perovskite-based Photoelectrochemical Devices for Solar Fuel and Chemical Production

Virgil Andrei^a

^aSchool of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 50, Singapore, Singapore

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

E4 Photo-assisted chemical reactions: materials, characterization and mechanisms

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Josep Albero Sancho and Diego Mateo Mateo

Oral, Virgil Andrei, presentation 259
Publication date: 15th December 2025

Metal halide perovskites have emerged as promising alternatives among established light absorbers, enabling unassisted PEC water splitting^[1,2] and CO₂ reduction to syngas.^[3,4] While the bare perovskite light absorber is rapidly degraded by moisture, recent developments in the device structure have led to substantial advances in the device stability. Here, I will give an overview of the latest progress in perovskite PEC devices, introducing design principles to improve their performance and reliability. For this purpose, I will discuss the role of charge selective layers in increasing the device photocurrent and photovoltage, by fine-tuning the band alignment and enabling efficient charge separation. A further beneficial effect of hydrophobicity is revealed by comparing devices with different hole transport layers (HTLs).^[1,2] On the manufacturing side, I will reveal new insights into how appropriate encapsulation techniques can extend the device lifetime to a few days under operation in aqueous media.^[2,3] To this end, low melting alloys are replaced with graphite epoxy paste as a conductive, hydrophobic and low-cost encapsulant.^[2,5] These design principles are successfully applied to an underexplored BiOI light absorber, increasing the photocathode stability towards hydrogen evolution from minutes to months.^[6] Finally, we will explore the next steps required for scalable solar fuels production, showcasing the latest progress in terms of device manufacturing. A suitable choice of materials can decrease the device cost tenfold and expand the device functionality, resulting in flexible, floating artificial leaves.^[4] Those materials are compatible with large-scale, automated fabrication processes, which present the most potential towards future real-world applications.^[7,8] Similar PEC systems approaching a m² size can take advantage of the modularity of artificial leaves,^[9] whereas thermoelectric generators can further bolster water splitting by utilizing waste heat to provide an additional Seebeck voltage.^[10,11] Lastly, I will introduce PEC devices as versatile platforms to produce value-added chemicals including C₂ hydrocarbons (ethene, ethylene) and glycerol oxidation products, by interfacing the perovskite semiconductor with copper nanoflower catalysts and silicon nanowires (Fig. 1).^[12]

References:

[1] Andrei, V. et al. Scalable Triple Cation Mixed Halide Perovskite–BiVO4 Tandems for Bias-Free Water Splitting. Adv. Energy Mater. 2018, 8, 1801403.

[2] Pornrungroj, C.; Andrei, V et al. Bifunctional Perovskite-BiVO4 Tandem Devices for Uninterrupted Solar and Electrocatalytic Water Splitting Cycles. Adv. Funct. Mater. 2021, 31, 2008182.

[3] Andrei, V.; Reuillard, B.; Reisner, E. Bias-free solar syngas production by integrating a molecular cobalt catalyst with perovskite–BiVO4 tandems. Nat. Mater. 2020, 19, 189–194.

[4] Andrei, V.; Ucoski, G. M. et al. Floating perovskite-BiVO4 devices for scalable solar fuel production. Nature 2022, 608, 518–522.

[5] Andrei, V.; Bethke, K.; Rademann, K. Adjusting the thermoelectric properties of copper (I) oxide–graphite–polymer pastes and the applications of such flexible composites Phys. Chem. Chem. Phys. 2016, 18, 10700–10707.

[6] Andrei, V.; Jagt, R. A. et al. Long-term solar water and CO2 splitting with photoelectrochemical BiOI–BiVO4 tandems. Nat. Mater. 2022, 21, 864–868.

[7] Sokol, K. P.; Andrei, V. Automated synthesis and characterization techniques for solar fuel production. Nat. Rev. Mater. 2022, 7, 251–253.

[8] Andrei, V.; Roh, I.; Yang, P. Nanowire photochemical diodes for artificial photosynthesis. Sci. Adv. 2023, 9, eade9044.

[9] Andrei, V.; Chiang, Y.-H.; Rahaman, M.; Anaya, M. et al. Modular perovskite-BiVO4 artificial leaves towards syngas synthesis on a m2 scale. Energy Environ. Sci. 2025, 18, 3623–3632.

[10] Andrei, V.; Bethke, K.; Rademann, K. Thermoelectricity in the context of renewable energy sources: joining forces instead of competing. Energy Environ. Sci. 2016, 9, 1528–1532.

[11] Pornrungroj, C.; Andrei, V.; Reisner, E. Thermoelectric–Photoelectrochemical Water Splitting under Concentrated Solar Irradiation. J. Am. Chem. Soc. 2023, 145, 13709–13714.

[12] Andrei, V.; Roh, I. et al. Perovskite-driven solar C2 hydrocarbon synthesis from CO2. Nat. Catal. 2025, 8, 137.

Acknowledgements:

This work was supported by Nanyang Technological University (Nanyang Assistant Professorship; V.A.) and St John’s College Cambridge (Title A Research Fellowship; V.A.).

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