Thickness Dilemma: A Simulation Study of the Performance of PM6:Y6-Based Organic Solar Cells
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The effect of active-layer thickness on PM6:Y6 organic solar cells' performance was studied using several characterization techniques, such as current density vs. voltage (J-V), capacitance vs. voltage (C-V), charge vs. voltage (Q-V), charge extraction by linearly increasing voltage (CELIV), and sun-dependent. Results show that increasing thickness increased light absorption and therefore short-circuit current density (JSC), but excessive thickness caused transport limitations and higher recombination, resulting in reduced fill factor (FF). On the other hand, open-circuit voltage (VOC) remained weakly dependent on thickness variation. As a result, power conversion efficiency (PCE) has initially increased and then declined beyond the optimum thickness. C-V and Q-V results indicated reduced charge extraction efficiency and increased series resistance in thick films. Recombination and mobility analyses showed higher loss rates and lower effective mobilities with increasing thickness, consistent with longer transport paths. CELIV confirmed more dispersive, trap-limited transport in thicker layers. Light-intensity-dependent JSC followed a near-linear dependence (α ≈ 1), and Suns-VOC measurements demonstrated thickness-insensitive voltage governed mainly by recombination kinetics.
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© 2023 The Author(s). Published by the College of Science, University of Baghdad. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License.
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1. B. J. Tremolet de Villers, R. C. MacKenzie, J. J. Jasieniak, N. D. Treat, and M. L. Chabinyc, Linking Vertical Bulk-Heterojunction Composition and Transient Photocurrent Dynamics in Organic Solar Cells with Solution-Processed MoOx Contact Layers, Adv. Energy Mater. 4(5), 1301290 (2014). https://doi.org/10.1002/aenm.201301290.
2. R. C. MacKenzie, A. Göritz, S. Greedy, E. von Hauff, and J. Nelson, Theory of Stark spectroscopy transients from thin film organic semiconducting devices, Phys. Rev. B 89(19), 195307 (2014). https://doi.org/10.1103/PhysRevB.89.195307.
3. R. Singh, E. Aluicio-Sarduy, Z. Kan, T. Ye, R. C. I. MacKenzie, and P. E. Keivanidis, Fullerene-Free Organic Solar Cells with an Efficiency of 3.7% Based on a Low-Cost Geometrically Planar Perylene Diimide Monomer, J. Mater. Chem. A. 2(35), 14348 (2014). https://doi.org/10.1039/C4TA02851A.
4. M. S. Salem, A. Shaker, and M. M. Salah, Device Modeling of Efficient PBDB-T: PZT-Based All-Polymer Solar Cell: Role of Band Alignment, Polym. 15(4), 869 (2023). https://doi.org/10.3390/polym15040869.
5. N. I. M. Ibrahim, A. M. Elharbi, and A. Albadri, Study the Effect of Thickness on the Performance of PM6:Y6 Organic Solar Using SCAPS Simulation, Adv. Mater. Phys. Chem. 14(14), 55 (2024). https://doi.org/10.4236/ampc.2024.144005.
6. S. A. Obaid, F. A. Senaed, and B. Y. Kadem, Impact of i-Layer Thickness on Band Alignments of a-Si:H Solar Cells: A Simulation Study Using SCAPS Software, Iraqi J. Appl. Phys. 22(1), 62 (2026).
7. M. Li, P. Huang, and H. Zhong, Current Understanding of Band-Edge Properties of Halide Perovskites: Urbach Tail, Rashba Splitting, and Exciton Binding Energy, J. Phys. Chem. Lett. 14(6), 1592 (2023). https://doi.org/10.1021/acs.jpclett.2c03525.
8. B. Bratina and E. Pavlica, Characterization of Charge Carrier Transport in Thin Organic Semiconductor Layers by Time-of-Flight Photocurrent Measurements, Org. Electron. 64, 117 (2019). https://doi.org/10.1016/j.orgel.2018.09.049.
9. W. Miao, Y. Liu, Y. Wu, J. Liang, J. Xiong, T. Hu, Y. He, L. Chen, J. Shan, X. Wang, and R. Yang, Energy Disorder Suppression, Charge Transport Channel Establishment by Integrating Four-Arm Donor Molecule for High-Performance Organic Solar Cells, Adv. Funct. Mater. 35(32), 2501143 (2025). https://doi.org/10.1002/adfm.202501143.
10. N. Tokmoldin, S. M. Hosseini, M. Raoufi, L. Q. Phuong, O. J. Sandberg, H. Guan, Y. Zou, D. Neher, and S. Shoaee, Extraordinarily long diffusion length in PM6:Y6 organic solar cells, J. Mater. Chem. A. 8(16), 7854 (2020). https://doi.org/10.1039/D0TA03016C.
11. F. Jannat, S. Ahmed, and M. A. Alim, Performance analysis of cesium formamidinium lead mixed halide based perovskite solar cell with MoOx as hole transport material via SCAPS-1D, Optik. 228, 166202 (2021). https://doi.org/10.1016/j.ijleo.2020.166202.
12. S. Chauhan and R. Singh, Unlocking the efficiency potential of tin-based perovskite solar cell, Pramana. 98(1), 28 (2024). https://doi.org/10.1007/s12043-023-02714-x.
13. B. Y. Kadem and R. F. Alfahed, Non-Fullerene OSC: The Effects of Active and Electron Transport Layers’ Thickness Towards 19.5% efficiency, JREEN 28(1), 39 (2025). https://doi.org/10.54966/jreen.v28i1.1275.
14. B. Y. Kadem, A. K. Hassan, and W. M. Cranton, Efficient P3HT:PCBM bulk heterojunction organic solar cells; effect of post deposition thermal treatment, J. Mater. Sci. Mater. Electron. 27, 7038 (2016). https://doi.org/10.1007/s10854-016-4661-8.
15. C. Chen, G. Wen, Z. Xiao, J. Peng, R. Hu, Z. Chen, C. Zhang, and W. Zhang, Charge Photogeneration and Recombination Dynamics in PTQ10:Y6 Solar Cells, Photonics 9, 892 (2022). https://doi.org/10.3390/photonics9120892.
16. M. E. A. Boudia, Q. Wang, and C. Zhao, Optimization of the Active Layer Thickness for Inverted Ternary Organic Solar Cells Achieves 20% Efficiency with Simulation, Sustainability 16(14), 6159 (2024). https://doi.org/10.3390/su16146159.
17. T. Kirchartz, T. Agostinelli, M. Campoy-Quiles, W. Gong, and J. Nelson, Understanding the Thickness-Dependent Performance of Organic Bulk Heterojunction Solar Cells: The Influence of Mobility, Lifetime, and Space Charge, J. Phys. Chem. Lett. 3(23), 3470 (2012). https://doi.org/10.1021/jz301639y.
18. D. He, L. Xie, Y. Bai, H. Zhang, L. Liu, J. Kong, Y. Chai, X. Li, M. Wang, Y. Zhang, and J. Zhang, Achieving High Fill Factor via Increasing Interfacial Disorder to Inhibit Bimolecular Recombination for Efficient Organic Solar Cells, Angew. Chem. Int. Ed., e202505722 (2025). https://doi.org/10.1002/anie.202505722.
19. V. Magnin and K. N’konou, Numerical Study of Charge Transport Layers in Inverted Ternary Organic Photovoltaic Cells, EPJ Photovoltaics 15, 29 (2024). https://doi.org/10.1051/epjpv/2024024.
20. G. Kumar, E. Lakhwani, W. Elmalem, W. T. S. Huck, A. Rao, N. C. Greenham, and R. H. Friend, Interface Limited Charge Extraction and Recombination in Organic Photovoltaics, Energy Environ. Sci. 7(7), 2227 (2014). https://doi.org/10.1039/C4EE00665H.
21. N. Gasparini, A. Salleo, I. McCulloch, and D. Baran, The Role of the Third Component in Ternary Organic Solar Cells, Nat. Rev. Mater. 4(4), 229242 (2019). https://doi.org/10.1038/s41578-019-0093-4.
22. K. Wang, C. Sun, C. Zhang, H. Bai, S. Sang, Y. Li, Z. Chen, J. Hu, X. Li, L. Meng, and Y. Li, Fine-Tuning of Film Morphology Through Addition of a Third Component Enables Organic Solar Cells with Efficiency Over 18%, Mater. Chem. Front. 8, 1 (2024). https://doi.org/10.1039/D4QM00231H.
23. G. Ding, S. T. Han, C.C. Kuo, V.A. Roy, and Y. Zhou, Porphyrin-Based Metal–Organic Frameworks for Neuromorphic Electronics, Small Structures, 4(2), 2200150 (2023). https://doi.org/10.1002/sstr.202200150.
24. H. Lu et al., Simultaneously Enhancing Exciton/Charge Transport in Organic Solar Cells by an Organoboron Additive, Adv. Mater. 34(42), 2205926 (2022). https://doi.org/10.1002/adma.202205926.
25. A. Mahmoudloo, Investigation of Charge Carrier Transport and Recombination in Organic Semiconductors with Charge Extraction by Linearly Increasing Voltage (CELIV) Technique, J. Appl. Res. Ind. Eng. 10(4), 575-583 (2023). https://doi.org/10.22105/jarie.2022.344217.1474.
26. J. Važgėla, K. Genevičius, and G. Juška, A Positivity-Preserving, Implicit Defect-Correction Multigrid Method for Turbulent Combustion, Chem. Phys. 478, 126 (2016). https://doi.org/10.1016/j.chemphys.2016.04.005.
27. D. Meng, J. Xue, Y. Zhao, E. Zhang, R. Zheng, and Y. Yang, Configurable Organic Charge Carriers toward Stable Perovskite Photovoltaics, Chem. Rev., 122(18) (2022), 14954. https://doi.org/10.1021/acs.chemrev.2c00166.
28. X. Du, X. Li, Q. Chen, H. Lin, and S. Tao, High performance organic solar cells based on ZnO: POT2T as an effective cathode interfacial layer, in J. Phys.: Conf. Ser. 1549, 042015 (2020). https://doi.org/10.1088/1742-6596/1549/4/042015.
29. H. Zerfaoui, D. Dib, and B. Y. Kadem, The Simulated Effects of Different Light Intensities on the SiC-Based Solar Cells, Silicon 11(4), 1917 (2019). https://doi.org/10.1007/s12633-018-0011-1.
30. Y. Kong, H. Chen, and L. Zuo, Understanding the Nonradiative Charge Recombination in Organic Photovoltaics: From Molecule to Device, Adva. Funct. Mater. 35(3), 2413864 (2025). https://doi.org/10.1002/adfm.202413864.