Abstract
The field of non-fullerene organic solar cells has experienced rapid development during the past few years, mainly driven by the development of novel non-fullerene acceptors and matching donor semiconductors. However, organic solar cell material development has progressed via a trial-and-error approach with limited understanding of the materials’ structure–property relationships and the underlying device physics of non-fullerene devices. In addition, the availability of hundreds of donor and acceptor semiconductors creates an extremely large pool of possible donor–acceptor combinations, which poses a daunting challenge for rational material screening and matching. This Review describes several important conceptual aspects of the emerging non-fullerene devices by highlighting key contributions that provided fundamental insights regarding rational material design, donor–acceptor pair matching, blend morphology control and the reduced voltage losses in non-fullerene organic solar cells. We also discuss the key challenges that need to be addressed to develop more-efficient non-fullerene organic solar cells.
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 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Lu, L. et al. Recent advances in bulk heterojunction polymer solar cells. Chem. Rev. 115, 12666–12731 (2015).
Dou, L., Liu, Y., Hong, Z., Li, G. & Yang, Y. Low-bandgap near-IR conjugated polymers/molecules for organic electronics. Chem. Rev. 115, 12633–12665 (2015).
He, Y. & Li, Y. Fullerene derivative acceptors for high performance polymer solar cells. Phys. Chem. Chem. Phys. 13, 1970–1983 (2011).
Liu, Y. et al. Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells. Nat. Commun. 5, 5293 (2014).
Zhao, J. B. et al. Efficient organic solar cells processed from hydrocarbon solvents. Nat. Energy 1, 15027 (2016).
He, Y., Chen, H.-Y., Hou, J. & Li, Y. Indene-C60 bisadduct: a new acceptor for high-performance polymer solar cells. J. Am. Chem. Soc. 132, 1377–1382 (2010).
Cheng, P. & Zhan, X. Stability of organic solar cells: challenges and strategies. Chem. Soc. Rev. 45, 2544–2582 (2016).
Koetse, M. M. et al. Efficient polymer:polymer bulk heterojunction solar cells. Appl. Phys. Lett. 88, 083504 (2006).
Zhan, X. et al. A high-mobility electron-transport polymer with broad absorption and its use in field-effect transistors and all-polymer solar cells. J. Am. Chem. Soc. 129, 7246–7247 (2007).
Dittmer, J. J., Marseglia, E. A. & Friend, R. H. Electron trapping in dye/polymer blend photovoltaic cells. Adv. Mater. 12, 1270–1274 (2000).
Holliday, S. et al. High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor. Nat. Commun. 7, 11585 (2016).
Zhao, W. et al. Molecular optimization enables over 13% efficiency in organic solar cells. J. Am. Chem. Soc. 139, 7148–7151 (2017). This paper demonstrates the significance of molecular optimization of both donor polymers and small molecular acceptors via fluorination to improve device performances.
He, Z. C. et al. Single-junction polymer solar cells with high efficiency and photovoltage. Nat. Photon. 9, 174–179 (2015).
Kawashima, K., Tamai, Y., Ohkita, H., Osaka, I. & Takimiya, K. High-efficiency polymer solar cells with small photon energy loss. Nat. Commun. 6, 10085 (2015).
Ran, N. A. et al. Harvesting the full potential of photons with organic solar cells. Adv. Mater. 28, 1482–1488 (2016).
Li, W., Hendriks, K. H., Furlan, A., Wienk, M. M. & Janssen, R. A. High quantum efficiencies in polymer solar cells at energy losses below 0.6 eV. J. Am. Chem. Soc. 137, 2231–2234 (2015).
Baran, D. et al. Reduced voltage losses yield 10% efficient fullerene free organic solar cells with 1 V open circuit voltages. Energy Environ. Sci. 9, 3783–3793 (2016).
Liu, J. et al. Fast charge separation in a non-fullerene organic solar cell with a small driving force. Nat. Energy 1, 16089 (2016). This paper, along with ref. 17, reports efficient non-fullerene organic solar cells with minimal driving forces and low voltage losses.
Yao, H. F. et al. Design, synthesis, and photovoltaic characterization of a small molecular acceptor with an ultra-narrow band gap. Angew. Chem. Int. Ed. 56, 3045–3049 (2017).
Zhang, J. et al. Ring-fusion of perylene diimide acceptor enabling efficient nonfullerene organic solar cells with a small voltage loss. J. Am. Chem. Soc. 139, 16092–16095 (2017).
Xu, X. et al. Realizing over 13% efficiency in green-solvent-processed nonfullerene organic solar cells enabled by 1,3,4-thiadiazole-based wide-bandgap copolymers. Adv. Mater. 30, 1703973 (2018).
Lin, Y. et al. An electron acceptor challenging fullerenes for efficient polymer solar cells. Adv. Mater. 27, 1170–1174 (2015). This paper is on efficient low-bandgap indacenodithiophene-based small molecular acceptors that boost the development of highly efficient non-fullerene organic solar cells.
Benduhn, J. et al. Intrinsic non-radiative voltage losses in fullerene-based organic solar cells. Nat. Energy 2, 17053 (2017).
Hendsbee, A. D. et al. Synthesis, self-assembly, and solar cell performance of N-annulated perylene diimide non-fullerene acceptors. Chem. Mater. 28, 7098–7109 (2016).
Gregg, B. A. & Hanna, M. C. Comparing organic to inorganic photovoltaic cells: Theory, experiment, and simulation. J. Appl. Phys. 93, 3605–3614 (2003).
Scharber, M. C. & Sariciftci, N. S. Efficiency of bulk-heterojunction organic solar cells. Prog. Polym. Sci. 38, 1929–1940 (2013).
Yao, J. Z. et al. Quantifying losses in open-circuit voltage in solution-processable solar cells. Phys. Rev. Appl. 4, 014020 (2015).
Credgington, D. & Durrant, J. R. Insights from transient optoelectronic analyses on the open-circuit voltage of organic solar cells. J. Phys. Chem. Lett. 3, 1465–1478 (2012).
Lakhwani, G., Rao, A. & Friend, R. H. Bimolecular recombination in organic photovoltaics. Annu. Rev. Phys. Chem. 65, 557–581 (2014).
Bin, H. et al. 11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor. Nat. Commun. 7, 13651 (2016).
Zhao, W. et al. Fullerene-free polymer solar cells with over 11% efficiency and excellent thermal stability. Adv. Mater. 28, 4734–4739 (2016).
Chen, S. et al. A Wide-bandgap donor polymer for highly efficient non-fullerene organic solar cells with a small voltage loss. J. Am. Chem. Soc. 139, 6298–6301 (2017).
Yu, G., Gao, J., Hummelen, J. C., Wudl, F. & Heeger, A. J. Polymer photovoltiac cells: Enhanced efficiencies via a network of internal donor-acceptor heterojunctions. Science 270, 1789–1791 (1995).
Halls, J. J. M. et al. Efficient photodiodes from interpenetrating polymer networks. Nature 376, 498–500 (1995).
Shu, Y. et al. A survey of electron-deficient pentacenes as acceptors in polymer bulk heterojunction solar cells. Chem. Sci. 2, 363–368 (2011).
Rajaram, S., Shivanna, R., Kandappa, S. K. & Narayan, K. S. Nonplanar perylene diimides as potential alternatives to fullerenes in organic solar cells. J. Phys. Chem. Lett. 3, 2405–2408 (2012).
Bloking, J. T. et al. Comparing the device physics and morphology of polymer solar cells employing fullerenes and non-fullerene acceptors. Adv. Energy Mater. 4, 1301426 (2014).
Wang, X. et al. Dimeric naphthalene diimide based small molecule acceptors: synthesis, characterization, and photovoltaic properties. Tetrahedron 70, 4726–4731 (2014).
Kim, Y. et al. Organic photovoltaic devices based on blends of regioregular poly(3-hexylthiophene) and poly(9.9-dioctylfluorene-co-benzothiadiazole). Chem. Mater. 16, 4812–4818 (2004).
Meng, D. et al. High-performance solution-processed non-fullerene organic solar cells based on selenophene-containing perylene bisimide acceptor. J. Am. Chem. Soc. 138, 375–380 (2016).
Sun, D. et al. Non-fullerene-acceptor-based bulk-heterojunction organic solar cells with efficiency over 7%. J. Am. Chem. Soc. 137, 11156–11162 (2015).
Zang, Y. et al. Integrated molecular, interfacial, and device engineering towards high-performance non-fullerene based organic solar cells. Adv. Mater. 26, 5708–5714 (2014).
Liu, Y. et al. A tetraphenylethylene core-based 3D structure small molecular acceptor enabling efficient non-fullerene organic solar cells. Adv. Mater. 27, 1015–1020 (2015).
Lin, H. et al. Reduced intramolecular twisting improves the performance of 3D molecular acceptors in non-fullerene organic solar cells. Adv. Mater. 28, 8546–8551 (2016).
Wu, Q., Zhao, D., Schneider, A. M., Chen, W. & Yu, L. Covalently bound clusters of alpha-substituted PDI-rival electron acceptors to fullerene for organic solar cells. J. Am. Chem. Soc. 138, 7248–7251 (2016).
Zhong, Y. et al. Molecular helices as electron acceptors in high-performance bulk heterojunction solar cells. Nat. Commun. 6, 8242 (2015). This paper, along with refs 20 and 48, reports promising perylene-diimide-based small molecular acceptors by the ring-fusing strategy.
Zhong, Y. et al. Efficient organic solar cells with helical perylene diimide electron acceptors. J. Am. Chem. Soc. 136, 15215–15221 (2014).
Meng, D. et al. Three-bladed rylene propellers with three-dimensional network assembly for organic electronics. J. Am. Chem. Soc. 138, 10184–10190 (2016).
Wu, Q. H. et al. Propeller-shaped acceptors for high-performance non-fullerene solar cells: importance of the rigidity of molecular geometry. Chem. Mater. 29, 1127–1133 (2017).
Li, S. et al. Design of a new small-molecule electron acceptor enables efficient polymer solar cells with high fill factor. Adv. Mater. 29, 1704051 (2017).
Xie, D. et al. A Novel thiophene-fused ending group enabling an excellent small molecule acceptor for high-performance fullerene-free polymer solar cells with 11.8% efficiency. Solar RRL 1, 1700044 (2017).
Lin, Y. Z. et al. Structure evolution of oligomer fused-ring electron acceptors toward high efficiency of as-cast polymer solar cells. Adv. Energy Mater. 6, 1600854 (2016).
Dai, S. et al. Fused nonacyclic electron acceptors for efficient polymer solar cells. J. Am. Chem. Soc. 139, 1336–1343 (2017).
Lin, Y. et al. High-performance electron acceptor with thienyl side chains for organic photovoltaics. J. Am. Chem. Soc. 138, 4955–4961 (2016).
Lin, Y. et al. A Facile planar fused-ring electron acceptor for as-cast polymer solar cells with 8.71% efficiency. J. Am. Chem. Soc. 138, 2973–2976 (2016).
Li, S. et al. Energy-level modulation of small-molecule electron acceptors to achieve over 12% efficiency in polymer solar cells. Adv. Mater. 28, 9423–9429 (2016).
Li, S. et al. Significant influence of the methoxyl substitution position on optoelectronic properties and molecular packing of small-molecule electron acceptors for photovoltaic cells. Adv. Energy Mater 7, 1700183 (2017).
Li, T. Y. et al. Small molecule near-infrared boron dipyrromethene donors for organic tandem solar cells. J. Am. Chem. Soc. 139, 13636–13639 (2017).
Heliatek sets new OPV world record efficiency of 13.2% Heliatek https://go.nature.com/2scgHMY (2016).
Claessens, C. G., Gonzalez-Rodriguez, D., Rodriguez-Morgade, M. S., Medina, A. & Torres, T. Subphthalocyanines, subporphyrazines, and subporphyrins: singular nonplanar aromatic systems. Chem. Rev. 114, 2192–2277 (2014).
de la Torre, G., Bottari, G. & Torres, T. Phthalocyanines and subphthalocyanines: Perfect partners for fullerenes and carbon nanotubes in molecular photovoltaics. Adv. Energy Mater. 7, 1601700 (2017).
Cnops, K. et al. 8.4% efficient fullerene-free organic solar cells exploiting long-range exciton energy transfer. Nat. Commun. 5, 3406 (2014).
Cnops, K. et al. Energy level tuning of non-fullerene acceptors in organic solar cells. J. Am. Chem. Soc. 137, 8991–8997 (2015).
Kobayashi, N., Ishizaki, T., Ishii, K. & Konami, H. Synthesis, spectroscopy, and molecular orbital calculations of subazaporphyrins, subphthalocyanines, subnaphthalocyanines, and compounds derived therefrom by ring expansion. J. Am. Chem. Soc. 121, 9096–9110 (1999).
Verreet, B. et al. A 4% Efficient organic solar cell using a fluorinated fused subphthalocyanine dimer as an electron acceptor. Adv. Energy Mater. 1, 565–568 (2011).
Li, Z. et al. Donor polymer design enables efficient non-fullerene organic solar cells. Nat. Commun. 7, 13094 (2016).
Zhou, N. J. et al. Morphology-performance relationships in high-efficiency all-polymer solar cells. Adv. Energy Mater. 4, 1300785 (2014).
Bauer, N. et al. Comparing non-fullerene acceptors with fullerene in polymer solar cells: a case study with FTAZ and PyCNTAZ. J. Mater. Chem. A 5, 4886–4893 (2017).
Ye, L. et al. High-efficiency nonfullerene organic solar cells: critical factors that affect complex multi-length scale morphology and device performance. Adv. Energy Mater. 7, 1602000 (2017).
Bin, H. et al. 9.73% Efficiency nonfullerene all organic small molecule solar cells with absorption-complementary donor and acceptor. J. Am. Chem. Soc. 139, 5085–5094 (2017).
Ye, L. et al. Quantitative relations between interaction parameter, miscibility and function in organic solar cells. Nat. Mater. 17, 253–260 (2018). This paper quantitatively correlates the Flory–Huggins interaction parameters, domain purity and device fill factors and provides a convenient method to pre-screen the promising donor–acceptor material combinations.
Hu, H. et al. Design of donor polymers with strong temperature-dependent aggregation property for efficient organic photovoltaics. Acc. Chem. Res. 50, 2519–2528 (2017).
Hu, H. et al. Terthiophene-based D-A polymer with an asymmetric arrangement of alkyl chains that enables efficient polymer solar cells. J. Am. Chem. Soc. 137, 14149–14157 (2015).
Qian, D. P. et al. Design, application, and morphology study of a new photovoltaic polymer with strong aggregation in solution state. Macromolecules 45, 9611–9617 (2012).
Dkhil, S. B. et al. Square-centimeter-sized high-efficiency polymer solar cells: how the processing atmosphere and film quality influence performance at large scale. Adv. Energy Mater. 6, 1600290 (2016).
Manor, A., Katz, E. A., Tromholt, T., Hirsch, B. & Krebs, F. C. Origin of size effect on efficiency of organic photovoltaics. J. Appl. Phys. 109, 074508 (2011).
Peters, C. H. et al. High efficiency polymer solar cells with long operating lifetimes. Adv. Energy Mater. 1, 491–494 (2011).
Li, N. et al. Abnormal strong burn-in degradation of highly efficient polymer solar cells caused by spinodal donor-acceptor demixing. Nat. Commun. 8, 14541 (2017).
Mateker, W. R. & McGehee, M. D. Progress in understanding degradation mechanisms and improving stability in organic photovoltaics. Adv. Mater. 29, 1603940 (2017).
Gasparini, N. et al. Burn-in free nonfullerene-based organic solar cells. Adv. Energy Mater. 7, 1700770 (2017). This paper, along with ref. 81, reports efficient non-fullerene organic solar cells with small burn-in losses of efficiencies compared with the benchmark fullerene-based devices.
Cha, H. et al. An efficient, ‘burn in’ free organic solar cell employing a nonfullerene electron acceptor. Adv. Mater. 29, 1701156 (2017).
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). This paper shows the use of the ternary strategy to simultaneously improve the efficiencies and stability of non-fullerene organic solar cells.
Wadsworth, A. et al. Highly efficient and reproducible nonfullerene solar cells from hydrocarbon solvents. ACS Energy Lett. 2, 1494–1500 (2017).
Duan, C. H., Huang, F. & Cao, Y. Solution processed thick film organic solar cells. Polym. Chem. 6, 8081–8098 (2015).
Wurfel, U., Neher, D., Spies, A. & Albrecht, S. Impact of charge transport on current-voltage characteristics and power-conversion efficiency of organic solar cells. Nat. Commun. 6, 6951 (2015). This paper, along with ref. 86, demonstrates the effect of charge mobility and charge recombination rate on the device fill factors of organic solar cells.
Bartelt, J. A., Lam, D., Burke, T. M., Sweetnam, S. M. & McGehee, M. D. Charge-carrier mobility requirements for bulk heterojunction solar cells with high fill factor and external quantum efficiency 90%. Adv. Energy Mater. 5, 1500577 (2015).
Yao, H. et al. Achieving highly efficient nonfullerene organic solar cells with improved intermolecular interaction and open-circuit voltage. Adv. Mater. 29, 1700254 (2017).
Gasparini, N. et al. Polymer:nonfullerene bulk heterojunction solar cells with exceptionally low recombination rates. Adv. Energy Mater. 7, 1701561 (2017).
Cui, Y. et al. Fine-tuned photoactive and interconnection layers for achieving over 13% efficiency in a fullerene-free tandem organic solar cell. J. Am. Chem. Soc. 139, 7302–7309 (2017). Two non-fullerene photovoltaic blends were fine-tuned to construct double-junction tandem cells, which provided a promising route to commercialization of organic solar cells with high efficiencies.
Qin, Y. et al. Achieving 12.8% efficiency by simultaneously improving open-circuit voltage and short-circuit current density in tandem organic solar cells. Adv. Mater. 29, 1606340 (2017).
Sun, C. et al. Interface design for high-efficiency non-fullerene polymer solar cells. Energy Environ. Sci. 10, 1784–1791 (2017).
Yu, J. et al. Boosting performance of inverted organic solar cells by using a planar coronene based electron-transporting layer. Nano Energy 39, 454–460 (2017).
Zhao, W., Li, S., Zhang, S., Liu, X. & Hou, J. Ternary polymer solar cells based on two acceptors and one donor for achieving 12.2% efficiency. Adv. Mater. 29, 1604059 (2017).
Lu, L. Y., Kelly, M. A., You, W. & Yu, L. P. Status and prospects for ternary organic photovoltaics. Nat. Photon. 9, 491–500 (2015).
Gasparini, N. et al. Designing ternary blend bulk heterojunction solar cells with reduced carrier recombination and a fill factor of 77%. Nat. Energy 1, 16118 (2016).
You, J. et al. A polymer tandem solar cell with 10.6% power conversion efficiency. Nat. Commun. 4, 1446 (2013).
Li, M. M. et al. Solution-processed organic tandem solar cells with power conversion efficiencies 12%. Nat. Photon. 11, 85–90 (2017).
Li, N. et al. Environmentally Printing efficient organic tandem solar cells with high fill factors: a guideline towards 20% power conversion efficiency. Adv. Energy Mater. 4, 1400084 (2014).
Guo, F., Ameri, T., Forberich, K. & Brabec, C. J. Semitransparent polymer solar cells. Polym. Int. 62, 1408–1412 (2013).
Wang, W. et al. Fused hexacyclic nonfullerene acceptor with strong near-infrared absorption for semitransparent organic solar cells with 9.77% efficiency. Adv. Mater. 29, 1701308 (2017). This paper reports semi-transparent organic solar cells approaching 10% efficiency based on a low-bandgap small molecular acceptor with strong near-infrared absorption.
Acknowledgements
H.Y. and J.Z. acknowledge financial support from the National Basic Research Program of China (973 Program; 2013CB834705), the Hong Kong Research Grants Council (T23–407/13-N, N_HKUST623/13, and 606012), the National Science Foundation of China (#21374090) and the Hong Kong Innovation and Technology Commission (ITC-CNERC14SC01). A.F. acknowledges the US National Science Foundation Materials Research Science and Engineering Centers program through the Northwestern University Materials Research Center (grant DMR-1121262) and US Air Force Office of Scientific Research (Grant FA9550-15-1-0044) for financial support. X.G. acknowledges financial support from National Science Foundation of China (51573076), Shenzhen Peacock Plan project (KQTD20140630110339343) and South University of Science and Technology of China (FRG-SUSTC1501A-72).
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Zhang, J., Tan, H.S., Guo, X. et al. Material insights and challenges for non-fullerene organic solar cells based on small molecular acceptors. Nat Energy 3, 720–731 (2018). https://doi.org/10.1038/s41560-018-0181-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41560-018-0181-5