Tailoring small-molecule acceptors through asymmetric side-chain substitution for efficient organic solar cells
Source abstract
Abstract
Abstract Side chain engineering of small-molecule acceptors (SMAs) is a promising strategy for improving device efficiency in organic solar cells (OSCs). This study investigates the parent SMAs of BT-BO and BT-TBO, along with the newly synthesized asymmetric SMA, BT-ASY, which features branched alkyl chains and thiophene side chains substituted at the β positions of the thiophene units, respectively. Despite exhibiting comparable optical and electrochemical properties, the PM6:BT-ASY-based device achieves a power conversion efficiency (PCE) of 18.08% representing a significant improvement over its symmetric counterparts. This enhancement is primarily attributed to improved charge mobility, extended carrier lifetimes, optimized molecular packing, and effective phase separation, as confirmed by grazing incidence wide-angle X-ray scattering measurements. Our findings highlight that asymmetric side-chain strategy enhances π-π stacking and electronic coupling, offering a simple yet effective approach to improving photovoltaic performance. This work underscores the potential of asymmetric structural modifications in SMAs for advancing OSC technology and renewable energy solutions.
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Research context
OpenAlex topics: Organic Electronics and Photovoltaics · Conducting polymers and applications · Perovskite Materials and Applications
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References (53)
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1. Cui Y, Xu Y, Yao H, et al. Single-junction organic photovoltaic cell with 19% efficiency. Adv Mater, 2021, 33: 210242010.1002/adma.202102420 ↗
2. Hou J, Inganäs O, Friend RH, et al. Organic solar cells based on non-fullerene acceptors. Nat Mater, 2018, 17: 119–12810.1038/nmat5063 ↗
3. Lu L, Zheng T, Wu Q, et al. Recent advances in bulk heterojunction polymer solar cells. Chem Rev, 2015, 115: 12666–1273110.1021/acs.chemrev.5b00098 ↗
4. Jia Z, Qin S, Meng L, et al. High performance tandem organic solar cells via a strongly infrared-absorbing narrow bandgap acceptor. Nat Commun, 2021, 12: 17810.1038/s41467-020-20431-6 ↗
5. Liao CY, Chen Y, Lee CC, et al. Processing strategies for an organic photovoltaic module with over 10% efficiency. Joule, 2020, 4: 189–20610.1016/j.joule.2019.11.006 ↗
6. Luo Z, Ma R, Yu J, et al. Heteroheptacene-based acceptors with thieno [3, 2-b]pyrrole yield high-performance polymer solar cells. Natl Sci Rev, 2022, 9: nwac07610.1093/nsr/nwac076 ↗
7. Meng L, Zhang Y, Wan X, et al. Organic and solution-processed tandem solar cells with 17.3% efficiency. Science, 2018, 361: 1094–109810.1126/science.aat2612 ↗
8. Yu H, Wang Y, Kwok CH, et al. A polymer acceptor with double-decker configuration enhances molecular packing for high-performance all-polymer solar cells. Joule, 2024, 8: 2304–232410.1016/j.joule.2024.06.010 ↗
9. Chen C, Wang L, Xia W, et al. Molecular interaction induced dual fibrils towards organic solar cells with certified efficiency over 20%. Nat Commun, 2024, 15: 686510.1038/s41467-024-51359-w ↗
10. Song J, Zhang C, Li C, et al. Non-halogenated solvent-processed organic solar cells with approaching 20 % efficiency and improved photostability. Angew Chem Int Ed, 2024, 63: e20240429710.1002/anie.202404297 ↗
11. Sun Y, Wang L, Guo C, et al. π-Extended nonfullerene acceptor for compressed molecular packing in organic solar cells to achieve over 20% efficiency. J Am Chem Soc, 2024, 146: 12011–1201910.1021/jacs.4c01503 ↗
12. Yuan J, Zhang Y, Zhou L, et al. Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core. Joule, 2019, 3: 1140–115110.1016/j.joule.2019.01.004 ↗
13. Chen L, Zhao C, Yu H, et al. Tailoring cyano substitutions on quinoxaline-based small-molecule acceptors enabling enhanced molecular packing for high-performance organic solar cells. Adv Energy Mater, 2024, 14: 240028510.1002/aenm.202400285 ↗
14. Huang J, Chen T, Mei L, et al. On the role of asymmetric molecular geometry in high-performance organic solar cells. Nat Commun, 2024, 15: 328710.1038/s41467-024-47707-5 ↗
15. Ma R, Yang T, Xiao Y, et al. Air-processed efficient organic solar cells from aromatic hydrocarbon solvent without solvent additive or post-treatment: insights into solvent effect on morphology. Energy Environ Mater, 2022, 5: 977–98510.1002/eem2.12226 ↗
16. Mazzio KA, Luscombe CK. The future of organic photovoltaics. Chem Soc Rev, 2015, 44: 78–9010.1039/C4CS00227J ↗
17. Tang Y, Xie L, Qiu D, et al. Optimizing the energy levels and crystallinity of 2,2′-bithiophene-3,3′-dicarboximide-based polymer donors for high-performance non-fullerene organic solar cells. J Mater Chem C, 2021, 9: 7575–758210.1039/D1TC01528A ↗
18. Xie L, Yang C, Zhou R, et al. Ternary organic solar cells based on two non-fullerene acceptors with complimentary absorption and balanced crystallinity. Chin J Chem, 2020, 38: 935–94010.1002/cjoc.201900554 ↗
19. Yu H, Luo S, Sun R, et al. A difluoro-monobromo end group enables high-performance polymer acceptor and efficient all-polymer solar cells processable with green solvent under ambient condition. Adv Funct Mater, 2021, 31: 210079110.1002/adfm.202100791 ↗
20. Yu H, Wang Y, Kim HK, et al. A vinylene-linker-based polymer acceptor featuring a coplanar and rigid molecular conformation enables high-performance all-polymer solar cells with over 17% efficiency. Adv Mater, 2022, 34: 220036110.1002/adma.202200361 ↗
21. Zou B, Ng HM, Yu H, et al. Precisely controlling polymer acceptors with weak intramolecular charge transfer effect and superior coplanarity for efficient indoor all-polymer solar cells with over 27% efficiency. Adv Mater, 2024, 36: 240540410.1002/adma.202405404 ↗
22. Yu H, Wang Y, Zou X, et al. Improved photovoltaic performance and robustness of all-polymer solar cells enabled by a polyfullerene guest acceptor. Nat Commun, 2023, 14: 232310.1038/s41467-023-37738-9 ↗
23. Jiang Y, Sun S, Xu R, et al. Non-fullerene acceptor with asymmetric structure and phenyl-substituted alkyl side chain for 20.2% efficiency organic solar cells. Nat Energy, 2024, 9: 975–98610.1038/s41560-024-01557-z ↗
24. Lee JW, Kim GU, Kim DJ, et al. Intrinsically-stretchable, efficient organic solar cells achieved by high-molecular-weight, electro-active polymer acceptor additives. Adv Energy Mater, 2022, 12: 220088710.1002/aenm.202200887 ↗
25. Li T, Wu Y, Zhou J, et al. Butterfly effects arising from starting materials in fused-ring electron acceptors. J Am Chem Soc, 2020, 142: 20124–2013310.1021/jacs.0c09800 ↗
26. Tang C, Ma X, Wang J-, et al. High-performance ladder-type heteroheptacene-based nonfullerene acceptors enabled by asymmetric cores with enhanced noncovalent intramolecular interactions. Angew Chem Int Ed, 2021, 60: 19314–1932310.1002/anie.202105861 ↗
27. Wang T, Cui Y, Ren J, et al. Asymmetric alkyl chain engineering for efficient and eco-friendly organic photovoltaic cells. Small, 2025, 21: 240830810.1002/smll.202408308 ↗
28. Yu H, Wang J, Zhou Q, et al. Semi-transparent organic photovoltaics. Chem Soc Rev, 2023, 52: 4132–414810.1039/D3CS00233K ↗
29. Zou B, Liang A, Ding P, et al. Dipole moment modulation of terminal groups enables asymmetric acceptors featuring medium bandgap for efficient and stable ternary organic solar cells. Angew Chem Int Ed, 2025, 64: e20241533210.1002/anie.202415332 ↗
30. Zou B, Wu W, Dela Peña TA, et al. Step-by-step modulation of crystalline features and exciton kinetics for 19.2% efficiency ortho-xylene processed organic solar cells. Nano-Micro Lett, 2024, 16: 3010.1007/s40820-023-01241-z ↗
31. Yu H, Zhao C, Hu H, et al. An efficient alkoxy-substituted polymer acceptor for efficient all-polymer solar cells with low voltage loss and versatile photovoltaic applications. Energy Environ Sci, 2024, 17: 5191–519910.1039/D4EE01804D ↗
32. Fan Q, Ma R, Yang J, et al. Unidirectional sidechain engineering to construct dual-asymmetric acceptors for 19.23 % efficiency organic solar cells with low energy loss and efficient charge transfer. Angew Chem Int Ed, 2023, 62: e20230830710.1002/anie.202308307 ↗
33. Hu H, Liu S, Xu J, et al. Over 19 % efficiency organic solar cells enabled by manipulating the intermolecular interactions through side chain fluorine functionalization. Angew Chem Int Ed, 2024, 63: e20240008610.1002/anie.202400086 ↗
34. Zhang J, Bai F, Angunawela I, et al. Alkyl-chain branching of non-fullerene acceptors flanking conjugated side groups toward highly efficient organic solar cells. Adv Energy Mater, 2021, 11: 210259610.1002/aenm.202102596 ↗
35. Shang A, Luo S, Zhang J, et al. Over 18% binary organic solar cells enabled by isomerization of non-fullerene acceptors with alkylthiophene side chains. Sci China Chem, 2022, 65: 1758–176610.1007/s11426-022-1290-y ↗
36. Chen S, Feng L, Jia T, et al. High-performance polymer solar cells with efficiency over 18% enabled by asymmetric side chain engineering of non-fullerene acceptors. Sci China Chem, 2021, 64: 1192–119910.1007/s11426-021-1013-0 ↗
37. Luo Z, Gao Y, Lai H, et al. Asymmetric side-chain substitution enables a 3D network acceptor with hydrogen bond assisted crystal packing and enhanced electronic coupling for efficient organic solar cells. Energy Environ Sci, 2022, 15: 4601–461110.1039/D2EE01848A ↗
38. Jin K, Xiao Z, Ding L. D18, an eximious solar polymer! J Semicond, 2021, 42: 01050210.1088/1674-4926/42/1/010502 ↗
39. Li C, Zhou J, Song J, et al. Non-fullerene acceptors with branched side chains and improved molecular packing to exceed 18% efficiency in organic solar cells. Nat Energy, 2021, 6: 605–61310.1038/s41560-021-00820-x ↗
40. Reb LK, Böhmer M, Predeschly B, et al. Perovskite and organic solar cells on a rocket flight. Joule, 2020, 4: 1880–189210.1016/j.joule.2020.07.004 ↗
41. Yu H, Wang Y, Zou X, et al. Effects of halogenation of small-molecule and polymeric acceptors for efficient organic solar cells. Adv Funct Mater, 2023, 33: 230071210.1002/adfm.202300712 ↗
42. Yuan J, Huang T, Cheng P, et al. Enabling low voltage losses and high photocurrent in fullerene-free organic photovoltaics. Nat Commun, 2019, 10: 57010.1038/s41467-019-08386-9 ↗
43. Gillett AJ, Privitera A, Dilmurat R, et al. The role of charge recombination to triplet excitons in organic solar cells. Nature, 2021, 597: 666–67110.1038/s41586-021-03840-5 ↗
44. Li Q, Chen Q, Li S, et al. Asymmetric non-fullerene acceptor based on a cyclohexane side chain for efficient organic solar cell. Org Electron, 2023, 114: 10673710.1016/j.orgel.2022.106737 ↗
45. Liang J, Pan M, Wang Z, et al. Branched alkoxy side chain enables high-performance non-fullerene acceptors with high open-circuit voltage and highly ordered molecular packing. Chem Mater, 2022, 34: 2059–206810.1021/acs.chemmater.1c03311 ↗
46. Liu S, Yuan J, Deng W, et al. High-efficiency organic solar cells with low non-radiative recombination loss and low energetic disorder. Nat Photonics, 2020, 14: 300–30510.1038/s41566-019-0573-5 ↗
47. Liu W, Yu H, Liu B, et al. Strengthening near-infrared photon harvesting in semi-transparent all-polymer solar cells through the synergy of fluorination on the selenide monomer backbone. Adv Funct Mater, 2024, 34: 240013110.1002/adfm.202400131 ↗
48. Yu H, Pan M, Sun R, et al. Regio-regular polymer acceptors enabled by determined fluorination on end groups for all-polymer solar cells with 15.2 % efficiency. Angew Chem Int Ed, 2021, 60: 10137–1014610.1002/anie.202016284 ↗
49. Zhan L, Li S, Li Y, et al. Desired open-circuit voltage increase enables efficiencies approaching 19% in symmetric-asymmetric molecule ternary organic photovoltaics. Joule, 2022, 6: 662–67510.1016/j.joule.2022.02.001 ↗
50. Chen Y, Bai F, Peng Z, et al. Asymmetric alkoxy and alkyl substitution on nonfullerene acceptors enabling high-performance organic solar cells. Adv Energy Mater, 2021, 11: 200314110.1002/aenm.202003141 ↗
51. Guo J, Xia X, Qiu B, et al. Manipulating polymer backbone configuration via halogenated asymmetric end-groups enables over 18% efficiency all-polymer solar cells. Adv Mater, 2023, 35: 221129610.1002/adma.202211296 ↗
52. Wang Z, Peng Z, Xiao Z, et al. Thermodynamic properties and molecular packing explain performance and processing procedures of three D18:NFA organic solar cells. Adv Mater, 2020, 32: 200538610.1002/adma.202005386 ↗
53. Liu W, Wu W, Sergeev AA, et al. Coplanar dimeric acceptors with bathochromic absorption and torsion-free backbones through precise fluorination enabling efficient organic photovoltaics with 18.63% efficiency. Adv Sci, 2025, 241082610.1002/advs.202410826 ↗