Abstract
Although the multiple-component (MC) blend strategy has been frequently used as a very effective way to improve the performance of organic solar cells (OSCs), there is a strong need to understand the fundamental working mechanism and material selection rule for achieving optimal MC-OSCs. Here we present the ‘dilution effect’ as the mechanism for MC-OSCs, where two highly miscible components are molecularly intermixed. Contrary to the aggregation-induced non-radiative decay, the dilution effect enables higher luminescence quantum efficiencies and open-circuit voltages (VOC) in MC-OSCs via suppressed electron–vibration coupling. The continuously broadened bandgap together with reduced electron–vibration coupling also explains the composition-dependent VOC in ternary blends well. Moreover, we show that electrons can transfer between different acceptors, depending on the energy offset between them, which contributes to the largely unperturbed charge transport and high fill factors in MC-OSCs. The discovery of the dilution effect enables the demonstration of a high power conversion efficiency of 18.31% in an MC-OSC.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Data availability
The data that support the findings of this study are available from the corresponding authors on reasonable request.
References
Yan, C. et al. Non-fullerene acceptors for organic solar cells. Nat. Rev. Mater. 3, 18003 (2018).
Hou, J., Inganäs, O., Friend, R. H. & Gao, F. Organic solar cells based on non-fullerene acceptors. Nat. Mater. 17, 119–128 (2018).
Cheng, P., Li, G., Zhan, X. & Yang, Y. Next-generation organic photovoltaics based on non-fullerene acceptors. Nat. Photon. 12, 131–142 (2018).
Bae, S.-H. et al. Printable solar cells from advanced solution-processible materials. Chem 1, 197–219 (2016).
Li, N., McCulloch, I. & Brabec, C. J. Analyzing the efficiency, stability and cost potential for fullerene-free organic photovoltaics in one figure of merit. Energy Environ. Sci. 11, 1355–1361 (2018).
Meng, L. et al. Organic and solution-processed tandem solar cells with 17.3% efficiency. Science 361, 1094–1098 (2018).
Zuo, L. et al. Polymer-modified halide perovskite films for efficient and stable planar heterojunction solar cells. Sci. Adv. 3, e1700106 (2017).
Yang, W. S. et al. Iodide management in formamidinium-lead-halide-based perovskite layers for efficient solar cells. Science 356, 1376–1379 (2017).
Li, S. et al. Asymmetric electron acceptors for high-efficiency and low-energy-loss organic photovoltaics. Adv. Mater. 32, 2001160 (2020).
Zhan, L. et al. Over 17% efficiency ternary organic solar cells enabled by two non-fullerene acceptors working in an alloy-like model. Energy Environ. Sci. 13, 635–645 (2020).
Lu, L., Kelly, M. A., You, W. & Yu, L. Status and prospects for ternary organic photovoltaics. Nat. Photon. 9, 491–500 (2015).
Yang, L., Yan, L. & You, W. Organic solar cells beyond one pair of donor–acceptor: Ternary blends and more. J. Phys. Chem. Lett. 4, 1802–1810 (2013).
Street, R. A., Davies, D., Khlyabich, P. P., Burkhart, B. & Thompson, B. C. Origin of the tunable open-circuit voltage in ternary blend bulk heterojunction organic solar cells. J. Am. Chem. Soc. 135, 986–989 (2013).
Khlyabich, P. P., Sezen-Edmonds, M., Howard, J. B., Thompson, B. C. & Loo, Y.-L. Formation of organic alloys in ternary-blend solar cells with two acceptors having energy-level offsets exceeding 0.4 eV. ACS Energy Lett. 2, 2149–2156 (2017).
Zhang, J. et al. Conjugated polymer–small molecule alloy leads to high efficient ternary organic solar cells. J. Am. Chem. Soc. 137, 8176–8183 (2015).
Khlyabich, P. P., Burkhart, B. & Thompson, B. C. Compositional dependence of the open-circuit voltage in ternary blend bulk heterojunction solar cells based on two donor polymers. J. Am. Chem. Soc. 134, 9074–9077 (2012).
Chen, Y. et al. Achieving high-performance ternary organic solar cells through tuning acceptor alloy. Adv. Mater. 29, 1603154 (2017).
Zhang, J. et al. Accurate determination of the minimum HOMO offset for efficient charge generation using organic semiconducting alloys. Adv. Energy Mater. 10, 1903298 (2020).
Liu, X., Yan, Y., Yao, Y. & Liang, Z. Ternary blend strategy for achieving high-efficiency organic solar cells with nonfullerene acceptors involved. Adv. Funct. Mater. 28, 1802004 (2018).
Kawamura, Y. et al. 100% phosphorescence quantum efficiency of Ir(III) complexes in organic semiconductor films. Appl. Phys. Lett. 86, 071104 (2005).
Zhang, Q. et al. Efficient blue organic light-emitting diodes employing thermally activated delayed fluorescence. Nat. Photon. 8, 326 (2014).
Bulović, V., Deshpande, R., Thompson, M. E. & Forrest, S. R. Tuning the color emission of thin film molecular organic light emitting devices by the solid state solvation effect. Chem. Phys. Lett. 308, 317–322 (1999).
Madigan, C. F. & Bulović, V. Solid state solvation in amorphous organic thin films. Phys. Rev. Lett. 91, 247403 (2003).
Northey, T., Stacey, J. & Penfold, T. J. The role of solid state solvation on the charge transfer state of a thermally activated delayed fluorescence emitter. J. Mater. Chem. C 5, 11001–11009 (2017).
Shi, X. et al. Design of a highly crystalline low-band gap fused-ring electron acceptor for high-efficiency solar cells with low energy loss. Chem. Mater. 29, 8369–8376 (2017).
Hong, Y., Lam, J. W. Y. & Tang, B. Z. Aggregation-induced emission: phenomenon, mechanism and applications. Chem. Commun. 29, 4332–4353 (2009).
Park, S. K. et al. Tailor-made highly luminescent and ambipolar transporting organic mixed stacked charge-transfer crystals: an isometric donor–acceptor approach. J. Am. Chem. Soc. 135, 4757–4764 (2013).
Slifkin, M. A. Charge transfer and excimer formation. Nature 200, 766–767 (1963).
Benduhn, J. et al. Intrinsic non-radiative voltage losses in fullerene-based organic solar cells. Nat. Energy 2, 17053 (2017).
Liu, X., Li, Y., Ding, K. & Forrest, S. Energy loss in organic photovoltaics: nonfullerene versus fullerene acceptors. Phys. Rev. Appl. 11, 024060 (2019).
de Jong, M., Seijo, L., Meijerink, A. & Rabouw, F. T. Resolving the ambiguity in the relation between Stokes shift and Huang–Rhys parameter. Phys. Chem. Chem. Phys. 17, 16959–16969 (2015).
Hong, Y., Lam, J. W. Y. & Tang, B. Z. Aggregation-induced emission. Chem. Soc. Rev. 40, 5361–5388 (2011).
Gasparini, N., Salleo, A., McCulloch, I. & Baran, D. The role of the third component in ternary organic solar cells. Nat. Rev. Mater. 4, 229–242 (2019).
Rau, U., Blank, B., Müller, T. C. M. & Kirchartz, T. Efficiency potential of photovoltaic materials and devices unveiled by detailed-balance analysis. Phys. Rev. Appl. 7, 044016 (2017).
Wang, Y. et al. Optical gaps of organic solar cells as a reference for comparing voltage losses. Adv. Energy Mater. 8, 1801352 (2018).
Baran, D. et al. Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells. Nat. Mater. 16, 363–369 (2017).
Liu, Y., Zuo, L., Shi, X., Jen, A. K. Y. & Ginger, D. S. Unexpectedly slow yet efficient picosecond to nanosecond photoinduced hole-transfer occurs in a polymer/nonfullerene acceptor organic photovoltaic blend. ACS Energy Lett. 3, 2396–2403 (2018).
Cha, H. et al. Influence of blend morphology and energetics on charge separation and recombination dynamics in organic solar cells incorporating a nonfullerene acceptor. Adv. Funct. Mater. 28, 1704389 (2018).
Ziffer, M. E. et al. Long-lived, non-geminate, radiative recombination of photogenerated charges in a polymer/small-molecule acceptor photovoltaic blend. J. Am. Chem. Soc. 140, 9996–10008 (2018).
Szarko, J. M. et al. Photovoltaic function and exciton/charge transfer dynamics in a highly efficient semiconducting copolymer. Adv. Funct. Mater. 24, 10–26 (2014).
Zhang, M., Wang, H., Tian, H., Geng, Y. & Tang, C. W. Bulk heterojunction photovoltaic cells with low donor concentration. Adv. Mater. 23, 4960–4964 (2011).
Bässler, H. Charge transport in disordered organic photoconductors a Monte Carlo simulation study. Phys. Status Solidi B 175, 15–56 (1993).
Kirkpatrick, S. Percolation and conduction. Rev. Mod. Phys. 45, 574–588 (1973).
Lim, D. U., Kim, S., Choi, Y. J., Jo, S. B. & Cho, J. H. Percolation-limited dual charge transport in vertical p–n heterojunction Schottky barrier transistors. Nano Lett. 20, 3585–3592 (2020).
Cui, Y. et al. Single-junction organic photovoltaic cells with approaching 18% efficiency. Adv. Mater. 32, 1908205 (2020).
Acknowledgements
This work was supported by the Office of Naval Research (grant nos. N00014-17-1-2201, N00014-20-1-2191), the Air Force Office of Scientific Research (grant no. FA9550-18-1-0046), the National Natural Science Foundation of China (grant no. 21734008) and National Key Research and Development programme of China (grant no. 2019YFA0705900). A.K.Y.J. thanks the support from the Boeing-Johnson Chair Professorship and Lee Shau Kee Chair Professorship in Materials Science. L.Z. thanks the support from the research startup fund of Zhejiang University.
Author information
Authors and Affiliations
Contributions
L.Z. conceived the idea, designed and carried out experiments on film/device fabrication and characterization, and analysed the data. S.B.J. designed, carried out and analysed spectroscopic studies, and modelled the percolation-limited charge transport. Y. Li fabricated and measured the champion devices. X.S. and F.L. synthesized the materials. Y.M. and R.J.S. carried out experiments on the electroluminescence and PL spectra. Y. Liu, D.S.G. and H.W.H. advised on theoretical analyses of luminescence behaviours. L.Z. and S.B.J. wrote the paper. A.K.Y.J. and H.C. supervised the research. All authors contributed to discussion, writing and revision.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Peer review information Nature Nanotechnology thanks the anonymous reviewers for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Experimental section, Supplementary Figs. 1–50, Appendices 1–5 and Tables 1–7.
Rights and permissions
About this article
Cite this article
Zuo, L., Jo, S.B., Li, Y. et al. Dilution effect for highly efficient multiple-component organic solar cells. Nat. Nanotechnol. 17, 53–60 (2022). https://doi.org/10.1038/s41565-021-01011-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41565-021-01011-1
This article is cited by
-
Understanding the AIE phenomenon of nonconjugated rhodamine derivatives via aggregation-induced molecular conformation change
Nature Communications (2024)
-
Efficient and stable organic solar cells enabled by multicomponent photoactive layer based on one-pot polymerization
Nature Communications (2023)
-
Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells
Nature Communications (2023)
-
An additive manufacturing approach based on electrohydrodynamic printing to fabricate P3HT:PCBM thin films
Scientific Reports (2023)
-
Suppressing electron-phonon coupling in organic photovoltaics for high-efficiency power conversion
Nature Communications (2023)