Decoupling Competing Roles of Energetic Disorder and Molecular Structural Order in Organic Photovoltaics

Kang X, Wang R, Wu J, An K, Yin Z, Lu F, Zhou Z, Wang Q, Lüer L, Wu H, Su SJ, Ying L, Brabec C, Li N (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Advanced Energy Materials Wiley

DOI: 10.1002/aenm.71301

Abstract

Minimizing non-radiative voltage loss remains a key challenge for organic solar cells (OSCs), yet the interplay between energetic disorder and molecular structural order is not well understood. By systematically varying polymer donors (PM6, PTzBI-dF, D18-Cl) blended with L8-BO, we decouple these factors using temperature-dependent open-circuit voltage (VOC) measurements. While a planar donor backbone (PTzBI-dF) promotes molecular packing and raises the ideal VOC limit (VOC, ideal) extrapolated to 0 K, it simultaneously induces severe energetic disorder. Temperature-dependent mobility analysis reveals significant Gaussian broadening parameters (σHOMO = 98 meV; σLUMO = 89 meV) for PTzBI-dF, leading to substantial non-radiative losses and a low room-temperature VOC. Crucially, the detrimental impact of energetic disorder outweighs the benefits of structural order, particularly below 200 K, where carrier thermalization into disorder induced tail states enhances non radiative recombination. These findings identify energetic disorder as the primary bottleneck to VOC and highlight the necessity of balancing molecular structural order with disorder suppression for next-generation OSC development.

Authors with CRIS profile

Rong Wang Institute Materials for Electronics and Energy Technology (i-MEET) Larry Lüer Institute Materials for Electronics and Energy Technology (i-MEET) Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET)

Involved external institutions

South China University of Technology (SCUT) / 华南理工大学 CN China (CN)

How to cite

APA:

Kang, X., Wang, R., Wu, J., An, K., Yin, Z., Lu, F.,... Li, N. (2026). Decoupling Competing Roles of Energetic Disorder and Molecular Structural Order in Organic Photovoltaics. Advanced Energy Materials. https://doi.org/10.1002/aenm.71301

MLA:

Kang, Xingwang, et al. "Decoupling Competing Roles of Energetic Disorder and Molecular Structural Order in Organic Photovoltaics." Advanced Energy Materials (2026).

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