Donor-Acceptor Molecular Bridges Orchestrate Interfacial Redox Dynamics for Durable NiOX-based Perovskite Solar Cells

Ramkrishna Das Adhikari^a, Deepak Yadav^b, Priyam Ghosh^b, Parameswar K. Iyer^a^,^b

^aCentre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

^bDepartment of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Poster, Ramkrishna Das Adhikari, 196
Publication date: 11th March 2026

The interfacial redox activity between the high-valence NiO_X and A/X site ions of perovskite, along with imbalanced charge extraction at the NiO_X/perovskite interface, induces severe non-radiative recombination in inverted perovskite solar cells (PSCs), limiting their efficiency and operational stability.^[1-3] To overcome these challenges, we rationally design two donor-acceptor (D-A) molecular modifiers, viz. TPA-IM and TPA-FM, incorporating distinct electron-withdrawing acceptor units to modulate molecular dipoles and interfacial coupling with perovskite and NiO_X. Combined theoretical and experimental characterization demonstrates that strong -CN-Ni and -CN-Pb²⁺ coordination interactions promote parallel molecular alignment on the NiO_X surface, enabling bilateral defect passivation and interfacial charge redistribution. This redistribution enhances the Ni³⁺/Ni²⁺ ratio, buried energy landscape and strengthens the built-in electric field, facilitating efficient hole extraction. Notably, TPA-FM, featuring stronger ICT and superior molecular packing, forms a compact and uniform interfacial layer that effectively regulates and suppresses detrimental interfacial redox activity. As a result, TPA-FM-modified devices exhibit enhanced perovskite quality, reduced trap-state densities, and minimized non-radiative losses, achieving a high PCE of 25.73% along with improved operational stability and suppressed ion migration. This work establishes a molecular design strategy to mitigate interfacial redox processes and optimize energy-level alignment at the NiO_X/perovskite interface for durable inverted PSCs.

References:

[1] Das Adhikari, R.; Baishya, H.; Patel, M. J.; Yadav, D.; Iyer, P. K. Bi-Directional Modification to Quench Detrimental Redox Reactions and Minimize Interfacial Energy Offset for NiOX/Perovskite-Based Solar Cells. Small 2024, 20 (46), e2404588.

[2] Das Adhikari, R.; Patel, M. J.; Baishya, H.; Yadav, D.; Kalita, M.; Alam, M.; Iyer, P. K. Decoding Recombination Dynamics in Perovskite Solar Cells: An in-Depth Critical Review. Chem. Soc. Rev. 2025, 54 (8), 3962–4034.

[3] Baishya, H.; Adhikari, R. D.; Patel, M. J.; Yadav, D.; Sarmah, T.; Alam, M.; Kalita, M.; Iyer, P. K. Defect Mediated Losses and Degradation of Perovskite Solar Cells: Origin, Impacts and Reliable Characterization Techniques. J. Energy Chem. 2024, 94, 217–253.

Acknowledgements:

The authors acknowledge financial support from the Department of Science and Technology (DST), India, under Project No. DST/TMD/IC-MAP/2K20/03. R. Das Adhikari (PMRF/1902720) sincerely acknowledges the Prime Minister’s Research Fellowship (PMRF), Ministry of Education, Government of India, for the award of the research fellowship.

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