Ionic liquids for efficient and stable perovskite solar cells: A comprehensive review
Subject Areas : Synthesis and Characterization of Nanostructures
Mohammad Saeed Rajabzade
1
,
Karim Abdizadeh
2
,
Fariba Tajabadi
3
*
,
Nima Taghavinia
4
*
1 - Center for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran.
2 - Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran.
3 - Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, Karaj, Iran.
4 - Nanoparticles and Coatings Lab, Department of Physics, Sharif University of Technology, Tehran, Iran.
Keywords: Ionic liquids, Perovskite solar cell, Green solvents, Solar cell fabrication process, Passivation.,
Abstract :
Perovskite solar cells have rapidly advanced in power conversion efficiency, reaching over 26% at the laboratory scale. However, transferring these impressive efficiencies to durable, large-scale devices remains a major challenge. A key bottleneck lies in the fabrication of high-quality perovskite layers, which typically relies on toxic and volatile solvents and additives that hinder scalability and long-term stability. Ionic liquids have been proposed as a versatile class of materials to overcome these challenges. Fundamentally, ionic liquids are organic salts that remain liquid at or near room temperature, characterized by negligible vapor pressure, thermal stability, and solubility. This review article provides a comprehensive perspective on the role of ionic liquids in perovskite photovoltaic technology. It examines the key applications and mechanisms by which ionic liquids enhance perovskite film quality, including controlled crystallization kinetics and defect passivation. Various synthesis and integration techniques for fabricating efficient perovskite solar cells without the use of toxic antisolvents are discussed in detail. Performance improvements and stability enhancements are also highlighted: ionic-liquid-engineered perovskite solar cells demonstrate efficiencies comparable to the best existing solar cells (20–24%) and exhibit significantly longer operational lifetimes under stress conditions. Through an analysis of recent studies, this review underscores that ionic liquids are not only suitable replacements for volatile solvents but also multifunctional additives capable of unlocking new levels of efficiency and stability in perovskite solar cells.
1. Wang, Z.; Li, Y.; Chen, X.; Li, X.; Xu, Z.; Liu, X.; Wang, L.; Zhang, W. Solution‐Processable Perovskite Solar Cells toward Commercialization: Progress and Challenges. Adv. Funct. Mater. 2019, 29 (47), 1907661. https://doi.org/10.1002/adfm.201807661
2. Ke, L.; Luo, S.; Ren, X.; Yuan, Y. Factors Influencing the Nucleation and Crystal Growth of Solution Processed Organic Lead Halide Perovskites: A Review. J. Phys. D: Appl. Phys. 2021, 54 (16), 163001. https://doi.org/10.1088/1361-6463/abd728
3. Meheretu, G. M.; Yihunie, M. T.; Wubetu, G. A. Performance and Stability of Hybrid Organic–Inorganic Perovskite Photovoltaics in Outdoor Illumination Conditions. Mater. Res. Express 2024, 5, 055514. https://doi.org/10.1088/2053-1591/ad495b
4. Li, X.; Nasti, G.; Dreessen, C.; Dagar, J.; Meitzner, R.; Amoroso, D.; Maffettone, P. L.; Kirchartz, T.; Unger, E.; Abate, A.; Dimitrov, S. D. Printing of tin perovskite solar cells via controlled crystallization. Sustain. Energy Fuels 2025, 9 (8), 2063–2071. https://doi.org/10.1039/d4se01321b
5. Lee, J.-W.; Lee, D.-K.; Jeong, D.-N.; Park, N.-G. Control of Crystal Growth toward Scalable Fabrication of Perovskite Solar Cells. Adv. Funct. Mater. 2018, 29 (47), 1807047. https://doi.org/10.1002/adfm.201807047
6. Zhang, K.; Zhang, X.; Brooks, K. G.; Ding, B.; Kinge, S.; Ding, Y.; Dai, S.; Nazeeruddin, M. K. Role of Ionic Liquids in Perovskite Solar Cells. Solar RRL 2023, 7 (11), 2300115. https://doi.org/10.1002/solr.202300115
7. Han, J.; Kim, R. H.; Huang, S.; Kim, J.; Yun, J. S. Green Solution Processing of Halide Perovskite Solar Cells: Status and Future Directions. Solar RRL 2024, 8 (22), 2400262. https://doi.org/10.1002/solr.202400262
8. Ma, J.; Wang, L.; He, K.; Sun, Y.; Li, B.; Zhao, Q.; Du, B. Progress and challenges: A review of ionic liquid treatment for efficient and stable perovskite solar cells. J. Mater. Chem. C 2024, 12, 10837–10856. https://doi.org/10.1039/d4tc01572j
9. Gu, H.; Niu, T.; Zuo, S.; Cai, Y.; Chao, L.; Müller-Buschbaum, P.; Xia, Y.; Zhang, J.; Xing, G.; Chen, Y. Stable Metal–Halide Perovskite Colloids in Protic Ionic Liquid. CCS Chem. 2022, 4 (10), 3264–3274. https://doi.org/10.31635/ccschem.022.202101629
10. Chen, Y.; Zhang, W.; Zhang, X.; et al. Room-Temperature Molten Salt for Facile Fabrication of Efficient and Stable Perovskite Solar Cells in Ambient Air. Chem 2019, 5 (4), 995–1005. https://doi.org/10.1016/j.chempr.2019.02.025
11. Wang, Z.; Li, Y.; Chen, X.; Li, X.; Xu, Z.; Liu, X.; Wang, L.; Zhang, W. Ionic Liquid Engineering in Perovskite Photovoltaics. Energy Environ. Mater. 2021, 4 (6), 12435. https://doi.org/10.1002/eem2.12435
12. Zhang, X.; Zhang, Y.; Li, Y.; et al. Solvent Engineering of Ionic Liquids for Stable and Efficient Perovskite Solar Cells. Adv. Energy Sustain. Res. 2022, 3 (11), 2200140. https://doi.org/10.1002/aesr.202200140
13. Wang, X.; Ran, X.; Liu, X.; Gu, H.; Zuo, S.; Hui, W.; Lu, H.; Sun, B.; Gao, X.; Zhang, J.; Xia, Y.; Chen, Y.; Huang, W. Tailoring Component Interaction for Air-Processed Efficient and Stable All-Inorganic Perovskite Photovoltaic. Angew. Chem. Int. Ed. 2020, 59 (32), 13354–13361. https://doi.org/10.1002/anie.202004256
14. Zhang, X.; Zhang, Y.; Li, Y.; et al. Revealing Size‐Dependency of Ionic Liquid to Assist Perovskite Film Formation. Small Methods 2023, 7 (11), 2300210. https://doi.org/10.1002/smtd.202300210
15. Xie, Y.; Wu, B.; Gao, D. Recent Advances in Ionic Molecules Applied in Perovskite Solar Cells. J. Mater. Chem. C 2024, 12, 6374–6394. https://doi.org/10.1039/d4tc00255e
16. Öz, Ş.; Burschka, J.; Jung, E.; et al. Protic Ionic Liquid Assisted Solution Processing of Lead Halide Perovskites with Water, Alcohols, and Acetonitrile. Nano Energy 2018, 51, 632–638. https://doi.org/10.1016/j.nanoen.2018.07.005
17. Zhao, Y.; Wang, Y.; Zhang, X.; et al. Designing Ionic Liquids as the Solvent for Efficient and Stable Perovskite Solar Cells. ACS Appl. Mater. Interfaces 2021, 13 (28), 33585–33593. https://doi.org/10.1021/acsami.1c21035
18. Zhang, Y.; Wang, Y.; Li, X.; et al. Solution Chemistry Strategies to Construct a Stable MAPbI₃ Film toward High-Performance Perovskite Solar Cells. Chem. Eng. J. 2024, 482, 148838. https://doi.org/10.1016/j.cej.2024.148838
19. Zhang, Y.; Liu, X.; Chen, Y.; et al. Acetate-Based Ionic Liquid Engineering for Efficient and Stable CsPbI₃ Perovskite Solar Cells. Mater. Today Phys. 2023, 28, 101301. https://doi.org/10.1016/j.mtphys.2023.101301
20. Huang, D.; Xie, P.; Pan, Z.; Rao, H.; Zhong, X. One-Step Solution Deposition of CsPbBr₃ Based on Precursor Engineering for Efficient All-Inorganic Perovskite Solar Cells. J. Mater. Chem. A 2019, 7, 22420–22428. https://doi.org/10.1039/c9ta08465g
21. Zhang, Y.; Zhang, X.; Zhang, Y.; et al. Room‐Temperature Molten Salt‐Mediated CsPbI₃ Growth for Efficient and Stable Perovskite Solar Cells. Adv. Energy Mater. 2023, 13 (35), 2303264. https://doi.org/10.1002/aenm.202303264
22. Chao, L.; Xia, Y.; Duan, X.; Wang, Y.; Ran, C.; Niu, T.; Gu, L.; Li, D.; Hu, J.; Gao, X.; Zhang, J.; Chen, Y. Direct and Stable α-Phase Formation via Ionic Liquid Solvation for Formamidinium-Based Perovskite Solar Cells. Joule 2022, 6 (9), 2203–2217. https://doi.org/10.1016/j.joule.2022.07.008
23. Hu, J.-F.; Chen, G.; Yu, S.-Z.; Lin, Y.-X.; Wang, K.-Y.; Li, Z.-W.; Zhang, G.-D.; Pan, T.-F.; Li, Y.-J.; Li, M.; Xia, Y.-D.; Lv, Y.-F.; Chen, Y.-H. Efficient Micrometer-Scale Thick-Film Perovskite Solar Cells with Superior Stability. Rare Metals 2024, 43 (4), 1647–1657. https://doi.org/10.1007/s12598-023-02529-0
24. Liu, G.; Lin, Z.; Tan, L.; et al. Significantly Improved Efficiency and Stability of Pure Tin-Based Perovskite Solar Cells with Bifunctional Molecules. ACS Appl. Mater. Interfaces 2023, 15 (28), 33643–33653. https://doi.org/10.1021/acsami.3c06070
25. Zhu, X.; Du, M.; Feng, J.; Wang, H.; Xu, Z.; Wang, L.; Zuo, S.; Wang, C.; Wang, Z.; Zhang, C.; Ren, X.; Priya, S.; Yang, D.; Liu, S. High-Efficiency Perovskite Solar Cells with Imidazolium-Based Ionic Liquid for Surface Passivation and Charge Transport. Angew. Chem. Int. Ed. 2021, 60 (8), 4238–4244. https://doi.org/10.1002/anie.202010987
26. Chao, L.; Niu, T.; Gu, H.; Yang, Y.; Wei, Q.; Xia, Y.; Hui, W.; Zuo, S.; Zhu, Z.; Pei, C.; Li, X.; Zhang, J.; Fang, J.; Xing, G.; Li, H.; Huang, X.; Gao, X.; Ran, C.; Song, L.; Fu, L.; Chen, Y.; Huang, W. Origin of High Efficiency and Long-Term Stability in Ionic Liquid Perovskite Photovoltaic. Research 2020, 2020, Article 2616345. https://doi.org/10.34133/2020/2616345
27. Zhang, J.; Lu, J.; Li, X.; Zhao, S.; Yang, Y.; Chen, P.; Cheng, H.; Zhou, L. Ionic Liquid assisted Defect Passivation for Efficient Carbon based Perovskite Solar Cells with Enhanced Filling Factor. ChemNanoMat 2024, 10 (9), e240050. https://doi.org/10.1002/cnma.202400050
28. Wang, F.; Sun, Y.; Wang, T.; Yang, G.; Li, Q.; Li, Y.; Lin, H.; Wan, X.; Li, G.; Hu, H. Ionic Liquid Additives for Efficient and Durable Two-Step Perovskite Photovoltaic Devices. Crystals 2023, 13 (9), 1370. https://doi.org/10.3390/cryst13091370
29. Li, Y.; Wang, F.; Li, Q.; Tang, B.; Sun, Y.; Wang, T.; Liang, X.; Ma, J.; Zhou, X.; Zhang, F.; Li, X.; Tong, Y.; Hu, R.; Yuan, M.; Wu, T.; Ng, A.; Hu, H. PTAA-Based Perovskite Photovoltaics Catching up: Ionic Liquid Engineering-Assisted Crystallization Through Sequential Deposition. Adv. Sci. 2025, 12 (15), Article 2414515. https://doi.org/10.1002/advs.202414515
30. Deng, X.; Xie, L.; Wang, S.; Li, C.; Wang, A.; Yuan, Y.; Cao, Z.; Li, T.; Ding, L.; Hao, F. Ionic Liquids Engineering for High-Efficiency and Stable Perovskite Solar Cells. Chem. Eng. J. 2020, 398, 125594. https://doi.org/10.1016/j.cej.2020.125594
31. Ahmed, Y.; Feng, X.; Gao, Y.; Ding, Y.; Long, C.; Haider, M.; Li, H.; Li, Z.; Huang, S.; Saidaminov, M. I.; Yang, J. Interface Modification by Ionic Liquid for Efficient and Stable FAPbI₃ Perovskite Solar Cells. Acta Phys. -Chim. Sin. 2024, 40 (6), Article 2303057. https://doi.org/10.3866/PKU.WHXB202303057
32. Lv, S.; Gao, W.; Ran, C.; Li, D.; Chao, L.; Wang, X.; Song, L.; Lin, Z.; Fu, L.; Chen, Y. Antisolvent-Free Fabrication of Efficient and Stable Sn–Pb Perovskite Solar Cells. Solar RRL 2021, 5 (11), 2100675. https://doi.org/10.1002/solr.202100675
33. Wang, T.; Zhang, T.; Zhang, J.; Zhao, B.; Song, C.; Yin, H.; Zhu, S.; Sun, X.; Liu, H.; Chen, Y.; Li, X. Additive-Regulated One-Step Dynamic Spin-Coating for Fabricating High-Performance Perovskite Solar Cells under High Humidity Conditions. J. Mater. Chem. C 2024, 12 (3), 913–921. https://doi.org/10.1039/d3tc03529h
34. Zhang, Y.; Li, X.; Wang, Y.; et al. Fabricate Anti-Solvent-Free Tin–Lead-Based Perovskite Solar Cells with MAAc-Added Ink. Proc. SPIE 12209, Thin Film Solar Technology XIII, 1220902 (2022). https://doi.org/10.1117/12.2634371
35. Fan, F.; Zhang, Y.; Hao, M.; Xin, F.; Zhou, Z.; Zhou, Y. Harnessing Chemical Functions of Ionic Liquids for Perovskite Solar Cells. J. Energy Chem. 2022, 68, 797–810. https://doi.org/10.1016/j.jechem.2021.11.038
36. Shi, L.; Yuan, H.; Sun, X.; Li, X.; Zhu, W.; Wang, J.; Duan, L.; Li, Q.; Zhou, Z.; Huang, Z.; Ban, X.; Zhang, D. MAAc Ionic Liquid-Assisted Defect Passivation for Efficient and Stable CsPbIBr₂ Perovskite Solar Cells. ACS Appl. Energy Mater. 2021, 4 (10), 10584–10592. https://doi.org/10.1021/acsaem.1c01537
37. Fang, J.; Ding, Z.; Chang, X.; Lu, J.; Yang, T.; Wen, J.; Fan, Y.; Zhang, Y.; Luo, T.; Chen, Y.; Liu, S.; Zhao, K. Microstructure and lattice strain control towards high-performance ambient green-printed perovskite solar cells. J. Mater. Chem. A 2021, 9 (22), 13297–13305. https://doi.org/10.1039/d1ta01763b
38. Xie, Y.; Chen, S.; Gu, Z.; Xu, K.; Chao, L.; Xia, Y. Role of Water in the Stability and Efficiency of Ionic Liquid-Based Perovskite Solar Cells. J. Phys. Chem. Lett. 2025, 16 (6), 1597–1603. https://doi.org/10.1021/acs.jpclett.4c03629
39. Zhang, Y.; Wang, Y.; Chen, Y.; et al. Constructing Additives Synergy Strategy to Doctor‐Blade Efficient and Stable Perovskite Solar Cells under High Humidity. Small 2023, 19 (24), 2300374. https://doi.org/10.1002/smll.202300374
40. Zhang, Y.; Wang, Y.; Chen, Y.; et al. Fully Screen‐Printed Perovskite Solar Cells with 17% Efficiency via Additive‐Assisted Ink Engineering. Adv. Energy Mater. 2023, 13 (1), 2302654. https://doi.org/10.1002/aenm.202302654
41. Chen, C.; Chen, J.; Han, H.; Chao, L.; Hu, J.; Niu, T.; Dong, H.; Yang, S.; Xia, Y.; Chen, Y.; Huang, W. Perovskite solar cells based on screen-printed thin films. Nature 2022, 612, 266–271. https://doi.org/10.1038/s41586-022-05346-0
42. Wang, J.; Wu, X.; Zhang, Y.; et al. Two-Step Perovskite Solar Cells with >25% Efficiency: Unveiling the Hidden Bottom Surface of Perovskite Layer. Adv. Mater. 2024, 36 (1), 2301476. https://doi.org/10.1002/adma.202401476
43. Akin, S.; Akman, E.; Sonmezoglu, S.; et al. FAPbI₃-Based Perovskite Solar Cells Employing Hexyl-Based Ionic Liquid with an Efficiency Over 20% and Excellent Long-Term Stability. Adv. Funct. Mater. 2020, 30 (28), 2002964. https://doi.org/10.1002/adfm.202002964
44. Lin, Z.; Su, Y.; Dai, R.; Liu, G.; Yang, J.; Sheng, W.; Zhong, Y.; Tan, L.; Chen, Y. Ionic Liquid-Induced Ostwald Ripening Effect for Efficient and Stable Tin-Based Perovskite Solar Cells. ACS Appl. Mater. Interfaces 2021, 13 (13), 15420–15428. https://doi.org/10.1021/acsami.1c01408
45. Sun, Y.; Hu, R.; Wang, F.; Wang, T.; Liang, X.; Zhou, X.; Yang, G.; Li, Y.; Zhang, F.; Zhu, Q.; Li, X.; Hu, H. Ionic liquid-regulated PbI₂ layers and defect passivation for efficient perovskite solar cells. J. Mater. Chem. C 2024, 12, 5175–5183. https://doi.org/10.1039/d4tc00500g
46. Liang, X.; Duan, D.; Al-Handawi, M. B.; Wang, F.; Zhou, X.; Ge, C.; Lin, H.; Zhu, Q.; Li, L.; Naumov, P.; Hu, H. The Role of Ionic Liquids in Performance Enhancement of Two-Step Perovskite Photovoltaics. Solar RRL 2022, 7 (1), 2200856. https://doi.org/10.1002/solr.202200856
47. Wang, J.; Zheng, X.; Zhang, C.; Chen, C.; Yao, Q.; Niu, T.; Chao, L.; Guo, Q.; Zhang, H.; Xia, Y.; Li, M.; Lu, H.; Do, H.; Chen, Z.; Xing, G.; Hu, Z.; Chen, Y. Multifunctional Anion Cation Modulation Engineering for Sn–Pb Perovskite Solar Cells. Nano Energy 2024, 128, 109851. https://doi.org/10.1016/j.nanoen.2024.109851
48. Peng, H.; Li, D.; Li, Z.; Xing, Z.; Hu, X.; Hu, T.; Chen, Y. Ionic Liquid Assisted Imprint for Efficient and Stable Quasi-2D Perovskite Solar Cells with Controlled Phase Distribution. Nano-Micro Lett. 2023, 15 (1), 91. https://doi.org/10.1007/s40820-023-01076-8
49. Zhang, Y.; Wang, Y.; Chen, Y.; et al. Ionic Liquid Tailoring Defect/Interface-Induced Recombination Loss in Dual-Junction Quasi-2D Perovskite Solar Cells. Chem. Eng. J. 2024, 481, 148586. https://doi.org/10.1016/j.cej.2024.148586
50. Kang, J.-H.; Chae, K.-H.; Kim, R.-H.; Jong, Y.-H.; Han, G.-J.; Kim, P. The Characteristics of Hole-Transport Material-Free Perovskite Solar Cells with Carbon Electrode Made by Using Ion Liquid Methylammonium Acetate Solvent. Results Opt. 2023, 13, 100510. https://doi.org/10.1016/j.rio.2023.100510
51. Guo, L.; Yang, X.; Yu, L.; Wu, Z.; San, X.; Zhang, X.; Zhang, H.; Chen, J.; Zhang, Y.; Wang, L.; Li, J.; Wang, Y.; Wang, J.; Xu, L. Synergistic Effect of Ionic Liquid and Embedded QDs on 2D Ferroelectric Perovskite Films with Narrow Phase Distribution for Self-Powered and Broad-Band Photodetectors. Nano Lett. 2024, 24 (12), 5480–5487. https://doi.org/10.1021/acs.nanolett.4c03143
52. Cao, F.; Zhu, Z.; Zhang, C.; Chen, P.; Wang, S.; Tong, A.; He, R.; Wang, Y.; Sun, W.; Li, Y.; Wu, J. Synergistic Ionic Liquid in Hole Transport Layers for Highly Stable and Efficient Perovskite Solar Cells. Small 2023, 19 (27), e2207784. https://doi.org/10.1002/smll.202207784
53. Li, D.; Chao, L.; Chen, C.; Ran, X.; Wang, Y.; Niu, T.; Lv, S.; Wu, H.; Xia, Y.; Ran, C.; Song, L.; Chen, S.; Chen, Y.; Huang, W. In Situ Interface Engineering for Highly Efficient Electron-Transport-Layer-Free Perovskite Solar Cells. Nano Lett. 2020, 20 (8), 5799–5806. https://doi.org/10.1021/acs.nanolett.0c01689
54. Yu, H.; Cao, B. A Green Ionic Liquid Solvent for Additive-Free, Efficient and Stable Bladed Perovskite Solar Cells under Ambient Conditions. New J. Chem. 2024, 48 (30), 13342–13349. https://doi.org/10.1039/d4nj01972e
55. Wang, D.; Zhang, Z.; Huang, T.; She, B.; Liu, B.; Chen, Y.; Wang, L.; Wu, C.; Xiong, J.; Huang, Y.; Zhang, J. Crystallization Kinetics Control Enabled by a Green Ionic Liquid Additive toward Efficient and Stable Carbon-Based Mesoscopic Perovskite Solar Cells. ACS Appl. Mater. Interfaces 2022, 14 (7), 9161–9171. https://doi.org/10.1021/acsami.1c23832
56. Sun, B.; Wang, W.; Lu, H.; Chao, L.; Gu, H.; Tao, L.; Hu, J.; Li, B.; Zong, X.; Shi, W.; Ran, X.; Zhang, H.; Xia, Y.; Li, P.; Chen, Y. Tuning the Interactions of Methylammonium Acetate with Acetonitrile to Create Efficient Perovskite Solar Cells. J. Phys. Chem. C 2021, 125 (12), 6555–6563. https://doi.org/10.1021/acs.jpcc.0c10805
57. Rajabzade, S.; Abdizadeh, K.; Mahyari, F. A.; Tajabadi, F.; Heidariramsheh, M.; Forouzandeh, M.; Taghavinia, N. Ionic liquid additive in ionic liquid based MAPbI₃ perovskite ink: Improved film crystallization and device performance in ambient air processed solar cells. J. Power Sources 2025, 630, 236134. https://doi.org/10.1016/j.jpowsour.2024.236134
58. Gu, L.; Ran, C.; Chao, L.; Bao, Y.; Hui, W.; Wang, Y.; Chen, Y.; Gao, X.; Song, L. Designing Ionic Liquids as the Solvent for Efficient and Stable Perovskite Solar Cells. ACS Appl. Mater. Interfaces 2022, 14 (20), 22870–22878. https://doi.org/10.1021/acsami.1c21035