Alkyl chain modulation of asymmetric hexacyclic fused acceptor synergistically with wide bandgap third component for high efficiency ternary organic solar cells

Abstract

Herein, two asymmetric hexacyclic fused small molecule acceptors (SMAs), namely BP4F-HU and BP4F-UU, were synthesized. The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film, thereby improving charge mobility and reducing energy loss within the corresponding film. Notably, the PM6:BP4F-UU device exhibited a higher open-circuit voltage (V _oc) of 0.878 V compared to the PM6:BP4F-HU device with a V _oc of 0.863 V. Further, a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices, which showed an ideal complementary absorption spectrum in PM6:BP4F-UU system. In addition, BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer (FRET) pathway, due to the good overlap between the photoluminescence (PL) spectrum of BTP-TA and the absorption region of BP4F-UU. Consequently, ternary devices with 15wt% BTP-TA exhibits broader photon utilization, optimal blend morphology, and reduced charge recombination compared to the corresponding binary devices. Consequently, PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency (PCE) of 17.83% with simultaneously increased V _oc of 0.905 V, short-circuit current density (J _sc) of 26.14 mA/cm², and fill factor (FF) of 75.38%.

Keywords

asymmetric hexacyclic acceptor / outside chain / wide bandgap acceptor / ternary organic solar cells

References

[[1]] Feng LL, Yuan J, Zhang ZZ, et al.. Thieno [3,2-b] pyrrolo-fused pentacyclic benzotriazole-based acceptor for efficient organic photovoltaics. ACS Appl. Mater. Interfaces, 2017, 9(37): 31985,

[[2]] Li M, Zhou YY, Zhang JQ, Song JS, Bo ZS. Tuning the dipole moments of nonfullerene acceptors with an asymmetric terminal strategy for highly efficient organic solar cells. J. Mater. Chem. A, 2019, 7(15): 8889,

[[3]] Jiang K, Wei QY, Lai JYL, et al.. Alkyl chain tuning of small molecule acceptors for efficient organic solar cells. Joule, 2019, 3(12): 3020,

[[4]] Liu S, Yuan J, Deng WY, et al.. High-efficiency organic solar cells with low non-radiative recombination loss and low energetic disorder. Nat. Photonics, 2020, 14(5): 300,

[[5]] Zhu C, Yuan J, Cai FF, et al.. Tuning the electron-deficient core of a non-fullerene acceptor to achieve over 17% efficiency in a single-junction organic solar cell. Energy Environ. Sci., 2020, 13(8): 2459,

[[6]] S.N. Bao, H. Yang, H.Y. Fan, et al., Volatilizable solid additive-assisted treatment enables organic solar cells with efficiency over 18.8% and fill factor exceeding 80, Adv. Mater., 33(2021), No. 48, art. No. 2105301.

[[7]] X.J. Chen, D. Wang, Z.K. Wang, et al., 18.02% efficiency ternary organic solar cells with a small-molecular donor third component, Chem. Eng. J., 424(2021), art. No. 130397.

[[8]] Y. Cui, Y. Xu, H.F. Yao, et al., Single-junction organic photovoltaic cell with 19% efficiency, Adv. Mater., 33(2021), No. 41, art. No. 2102420.

[[9]] L.Z. Liu, S.Y. Chen, Y.Y. Qu, et al., Nanographene-osmapentalyne complexes as a cathode interlayer in organic solar cells enhance efficiency over 18%, Adv. Mater., 33(2021), No. 30, art. No. 2101279.

[[10]] Ma RJ, Yang T, Xiao YQ, 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(3): 977,

[[11]] G.U. Kim, C. Sun, D. Lee, et al., Effect of the selective halogenation of small molecule acceptors on the blend morphology and voltage loss of high-performance solar cells, Adv. Funct. Mater., 32(2022), No. 25, art. No. 2201150.

[[12]] G.L. Cai, Z. Chen, X.X. Xia, et al., Pushing the efficiency of high open-circuit voltage binary organic solar cells by vertical morphology tuning, Adv. Sci., 9(2022), No. 14, art. No. 2200578.

[[13]] Lin F, Jiang K, Kaminsky W, Zhu ZL, Jen AKY. A non-fullerene acceptor with enhanced intermolecular π-core interaction for high-performance organic solar cells. J. Am. Chem. Soc., 2020, 142(36): 15246,

[[14]] Z.C. Zhou, W.R. Liu, G.Q. Zhou, et al., Subtle molecular tailoring induces significant morphology optimization enabling over 16% efficiency organic solar cells with efficient charge generation, Adv. Mater., 32(2020), No. 4, art. No. 1906324.

[[15]] Y. Cui, H.F. Yao, J.Q. Zhang, et al., Single-junction organic photovoltaic cells with approaching 18% efficiency, Adv. Mater., 32(2020), No. 19, art. No. 1908205.

[[16]] Li C, Zhou JD, Song JL, 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(6): 605,

[[17]] Luo ZH, Ma RJ, Liu T, et al.. Fine-tuning energy levels via asymmetric end groups enables polymer solar cells with efficiencies over 17%. Joule, 2020, 4(6): 1236,

[[18]] Chen H, Lai HJ, Chen ZY, et al.. 17.1%-efficient eco-compatible organic solar cells from a dissymmetric 3D network acceptor. Angew. Chem. Int. Ed., 2021, 60(6): 3238,

[[19]] F. Liu, L. Zhou, W.R. Liu, et al., Organic solar cells with 18% efficiency enabled by an alloy acceptor: A two-in-one strategy, Adv. Mater., 33(2021), No. 27, art. No. 2100830.

[[20]] Y.H. Cai, Y. Li, R. Wang, et al., A well-mixed phase formed by two compatible non-fullerene acceptors enables ternary organic solar cells with efficiency over 18.6%, Adv. Mater., 33(2021), No. 33, art. No. 2101733.

[[21]] T. Zhang, C.B. An, P.Q. Bi, et al., A thiadiazole-based conjugated polymer with ultradeep HOMO level and strong electroluminescence enables 18.6% efficiency in organic solar cell, Adv. Energy Mater., 11(2021), No. 35, art. No. 2101705.

[[22]] G.C. Liu, R.X. Xia, Q.R. Huang, et al., Tandem organic solar cells with 18.7% efficiency enabled by suppressing the charge recombination in front sub-cell, Adv. Funct. Mater., 31(2021), No. 29, art. No. 2103283.

[[23]] J.Q. Wang, Z. Zheng, Y.F. Zu, et al., A tandem organic photovoltaic cell with 19.6% efficiency enabled by light distribution control, Adv. Mater., 33(2021), No. 39, art. No. 2102787.

[[24]] Zheng Z, Wang JQ, Bi PQ, et al.. Tandem organic solar cell with 20.2% efficiency. Joule, 2022, 6(1): 171,

[[25]] X.J. Zheng, L.J. Zuo, F. Zhao, et al., High-efficiency ITO-free organic photovoltaics with superior flexibility and upscalability, Adv. Mater., 34(2022), No. 17, art. No. 2200044.

[[26]] J. Yao, B.B. Qiu, Z.G. Zhang, et al., Cathode engineering with perylene-diimide interlayer enabling over 17% efficiency single-junction organic solar cells, Nat. Commun., 11(2020), No. 1, art. No. 2726.

[[27]] Lv J, Tang H, Huang JM, et al.. Additive-induced miscibility regulation and hierarchical morphology enable 17.5% binary organic solar cells. Energy Environ. Sci., 2021, 14(5): 3044,

[[28]] Xu XP, Yu LY, Yan H, Li RP, Peng Q. Highly efficient non-fullerene organic solar cells enabled by a delayed processing method using a non-halogenated solvent. Energy Environ. Sci., 2020, 13(11): 4381,

[[29]] Zhu L, Zhang M, Xu JQ, et al.. Single-junction organic solar cells with over 19% efficiency enabled by a refined double-fibril network morphology. Nat. Mater., 2022, 21(6): 656,

[[30]] L.L. Zhan, S.C. Yin, Y.K. Li, et al., Multiphase morphology with enhanced carrier lifetime via quaternary strategy enables high-efficiency thick-film, and large-area organic photovoltaics, Adv. Mater., 34(2022), No. 45, art. No. 2206269.

[[31]] Zhang JQ, Tan HS, Guo XG, Facchetti A, Yan H. Material insights and challenges for non-fullerene organic solar cells based on small molecular acceptors. Nat. Energy, 2018, 3(9): 720,

[[32]] Zhang ZZ, Li YW, Cai GL, Zhang YH, Lu XH, Lin YZ. Selenium heterocyclic electron acceptor with small urbach energy for as-cast high-performance organic solar cells. J. Am. Chem. Soc., 2020, 142(44): 18741,

[[33]] Cai FF, Peng HJ, Chen HG, et al.. An asymmetric small molecule acceptor for organic solar cells with a short circuit current density over 24 mA·cm⁻². J. Mater. Chem. A, 2020, 8(31): 15984,

[[34]] W. Gao, H.T. Fu, Y.X. Li, et al., Asymmetric acceptors enabling organic solar cells to achieve an over 17% efficiency: Conformation effects on regulating molecular properties and suppressing nonradiative energy loss, Adv. Energy Mater., 11(2021), No. 4, art. No. 2003177.

[[35]] Y.Z. Chen, F.J. Bai, Z.X. Peng, et al., Asymmetric alkoxy and alkyl substitution on nonfullerene acceptors enabling high-performance organic solar cells, Adv. Energy Mater., 11(2021), No. 3, art. No. 2003141.

[[36]] L.Y. Su, H.H. Huang, Y.C. Lin, et al., Enhancing long-term thermal stability of non-fullerene organic solar cells using self-assembly amphiphilic dendritic block copolymer interlayers, Adv. Funct. Mater., 31(2021), No. 4, art. No. 2005753.

[[37]] J.S. Song and Z.S. Bo, Asymmetric molecular engineering in recent nonfullerene acceptors for efficient organic solar cells, Chin. Chem. Lett., 34(2023), No. 10, art. No. 108163.

[[38]] Luo ZH, Gao Y, Lai HJ, 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(11): 4601,

[[39]] Zhang X, Li CQ, Qin LQ, et al.. Side-chain engineering for enhancing the molecular rigidity and photovoltaic performance of noncovalently fused-ring electron acceptors. Angew. Chem. Int. Ed., 2021, 60(32): 17720,

[[40]] Y.L. Yin, L.L. Zhan, M. Liu, et al., Boosting photovoltaic performance of ternary organic solar cells by integrating a multifunctional guest acceptor, Nano Energy, 90(2021), art. No. 106538.

[[41]] Zhan LL, Li SX, Li YK, et al.. Desired open-circuit voltage increase enables efficiencies approaching 19% in symmetric-asymmetric molecule ternary organic photovoltaics. Joule, 2022, 6(3): 662,

[[42]] Guo XW, Li DQ, Zhang YX, et al.. Understanding the effect of N2200 on performance of J71:ITIC bulk heterojunction in ternary non-fullerene solar cells. Org. Electron., 2019, 71: 65,

[[43]] J. Lee, S.M. Lee, S. Chen, et al., Organic photovoltaics with multiple donor–acceptor pairs, Adv. Mater., 31(2019), No. 20, art. No. 1804762.

[[44]] Cai FF, Zhu C, Yuan J, et al.. Efficient organic solar cells based on a new “Y-series” non-fullerene acceptor with an asymmetric electron-deficient-core. Chem. Commun., 2020, 56(31): 4340,

[[45]] Xiao LG, Kolaczkowski MA, Min YG, Liu Y. Substitution effect on thiobarbituric acid end groups for high open-circuit voltage non-fullerene organic solar cells. ACS Appl. Mater. Interfaces, 2020, 12(37): 41852,

[[46]] N.Y. Doumon, L.L. Yang, and F. Rosei, Ternary organic solar cells: A review of the role of the third element, Nano Energy, 94(2022), art. No. 106915.

[[47]] L.C. Chang, M. Sheng, L.P. Duan, and A. Uddin, Ternary organic solar cells based on non-fullerene acceptors: A review, Org. Electron., 90(2021), art. No. 106063.

[[48]] Y.J. Cheng, B. Huang, X.X. Huang, et al., Oligomer-assisted photoactive layers enable >18% efficiency of organic solar cells, Angew. Chem. Int. Ed., 61(2022), No. 21, art. No. e202200329.

[[49]] Z.P. Yu, Z.X. Liu, F.X. Chen, et al., Simple non-fused electron acceptors for efficient and stable organic solar cells, Nat. Commun., 10(2019), art. No. 2152.

[[50]] Yuan J, Zhang CJ, Chen HG, et al.. Understanding energetic disorder in electron-deficient-core-based non-fullerene solar cells. Sci. China Chem., 2020, 63(8): 1159,

[[51]] B. Qiu, Z. Chen, S. Qin, et al., Highly efficient all-small-molecule organic solar cells with appropriate active layer morphology by side chain engineering of donor molecules and thermal annealing, Adv. Mater., 32(2020), No. 21, art. No. 1908373.

[[52]] Li SX, Zhan LL, Sun CK, et al.. Highly efficient fullerene-free organic solar cells operate at near zero highest occupied molecular orbital offsets. J. Am. Chem. Soc., 2019, 141(7): 3073,

[[53]] J.N. Song, M. Zhang, M. Yuan, Y.H. Qian, Y.M. Sun, and F. Liu, Morphology characterization of bulk heterojunction solar cells, Small Methods, 2(2018), No. 3, art. No. 1700229.