Organic solar cells have desirable properties, including low cost of materials, high-throughput roll-to-roll production, mechanical flexibility and light weight. However, all top-performance devices are at present processed using halogenated solvents, which are environmentally hazardous and would thus require expensive mitigation to contain the hazards. Attempts to process organic solar cells from non-halogenated solvents lead to inferior performance. Overcoming this hurdle, here we present a hydrocarbon-based processing system that is not only more environmentally friendly but also yields cells with power conversion efficiencies of up to 11.7%. Our processing system incorporates the synergistic effects of a hydrocarbon solvent, a novel additive, a suitable choice of polymer side chain, and strong temperature-dependent aggregation of the donor polymer. Our results not only demonstrate a method of producing active layers of organic solar cells in an environmentally friendly way, but also provide important scientific insights that will facilitate further improvement of the morphology and performance of organic solar cells.
Your institute does not have access to this article
Open Access articles citing this article.
Nature Communications Open Access 07 June 2022
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Yu, G., Gao, J., Hummelen, J. C., Wudl, F. & Heeger, A. J. Polymer photovoltaic cells-enhanced efficiencies via a network of internal donor–acceptor heterojunctions. Science 270, 1789–1791 (1995).
Li, G. et al. High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends. Nature Mater. 4, 864–868 (2005).
Kim, J. Y. et al. Efficient tandem polymer solar cells fabricated by all-solution processing. Science 317, 222–225 (2007).
Peet, J. et al. Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols. Nature Mater. 6, 497–500 (2007).
Chen, H.-Y. et al. Polymer solar cells with enhanced open-circuit voltage and efficiency. Nature Photon. 3, 649–653 (2009).
Park, S. H. et al. Bulk heterojunction solar cells with internal quantum efficiency approaching 100%. Nature Photon. 3, 297–302 (2009).
He, Z. et al. Enhanced power-conversion efficiency in polymer solar cells using an inverted device structure. Nature Photon. 6, 591–595 (2012).
Guo, X. et al. Polymer solar cells with enhanced fill factors. Nature Photon. 7, 825–833 (2013).
Heeger, A. J. 25th anniversary article: bulk heterojunction solar cells: understanding the mechanism of operation. Adv. Mater. 26, 10–28 (2014).
Liu, Y. et al. Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells. Nature Commun. 5, 5293 (2014).
He, Z. et al. Single-junction polymer solar cells with high efficiency and photovoltage. Nature Photon. 9, 174–179 (2015).
You, J. et al. A polymer tandem solar cell with 10.6% power conversion efficiency. Nature Commun. 4, 1446 (2013).
Zhou, H. et al. Polymer homo-tandem solar cells with best efficiency of 11.3%. Adv. Mater. 27, 1767–1773 (2015).
Yusoff, A. R. b. M. et al. A high efficiency solution processed polymer inverted triple-junction solar cell exhibiting a power conversion efficiency of 11.83%. Energy Environ. Sci. 8, 303–316 (2015).
Shaheen, S. E. et al. 2.5% efficient organic plastic solar cells. Appl. Phys. Lett. 78, 841–843 (2001).
Chueh, C.-C. et al. Non-halogenated solvents for environmentally friendly processing of high-performance bulk-heterojunction polymer solar cells. Energy Environ. Sci. 6, 3241–3248 (2013).
Chen, X., Liu, X., Burgers, M. A., Huang, Y. & Bazan, G. C. Green-solvent-processed molecular solar cells. Angew. Chem. Int. Ed. 53, 14378–14381 (2014).
Guo, X., Zhang, M., Cui, C., Hou, J. & Li, Y. Efficient polymer solar cells based on poly(3-hexylthiophene) and indene–C60 bisadduct fabricated with non-halogenated solvents. ACS Appl. Mater. Interfaces 6, 8190–8198 (2014).
Synooka, O., Eberhardt, K. R. & Hoppe, H. Chlorine-free processed high performance organic solar cells. RSC Adv. 4, 16681–16685 (2014).
Deng, Y. et al. Low bandgap conjugated polymers based on mono-fluorinated isoindigo for efficient bulk heterojunction polymer solar cells processed with non-chlorinated solvents. Energy Environ. Sci. 8, 585–591 (2015).
Sprau, C. et al. Highly efficient polymer solar cells cast from non-halogenated xylene/anisaldehyde solution. Energy Environ. Sci. 8, 2744–2752 (2015).
Zhao, W., Ye, L., Zhang, S., Sun, M. & Hou, J. A universal halogen-free solvent system for highly efficient polymer solar cells. J. Mater. Chem. A 3, 12723–12729 (2015).
Huang, Y., Kramer, E. J., Heeger, A. J. & Bazan, G. C. Bulk heterojunction solar cells: morphology and performance relationships. Chem. Rev. 114, 7006–7043 (2014).
Scrivens, W. A. & Tour, J. M. Potent solvents for C60 and their utility for the rapid acquisition of 13C NMR data for fullerenes. J. Chem. Soc. Chem. Commun. 1207–1209 (1993).
Lee, J. K. et al. Processing additives for improved efficiency from bulk heterojunction solar cells. J. Am. Chem. Soc. 130, 3619–3623 (2008).
Ruoff, R. S., Tse, D. S., Malhotra, R. & Lorents, D. C. Solubility of fullerene (C60) in a variety of solvents. J. Phys. Chem. 97, 3379–3383 (1993).
Swaraj, S. et al. Nanomorphology of bulk heterojunction photovoltaic thin films probed with resonant soft X-ray scattering. Nano Lett. 10, 2863–2869 (2010).
Collins, B. A. et al. Absolute measurement of domain composition and nanoscale size distribution explains performance in PTB7:PC71BM solar cells. Adv. Energy Mater. 3, 65–74 (2013).
Chen, W. et al. Hierarchical nanomorphologies promote exciton dissociation in polymer/fullerene bulk heterojunction solar cells. Nano Lett. 11, 3707–3713 (2011).
Shaw, P. E., Ruseckas, A. & Samuel, I. D. W. Exciton diffusion measurements in poly(3-hexylthiophene). Adv. Mater. 20, 3516–3520 (2008).
Stuart, A. C. et al. Fluorine substituents reduce charge recombination and drive structure and morphology development in polymer solar cells. J. Am. Chem. Soc. 135, 1806–1815 (2013).
Albrecht, S. et al. Quantifying charge extraction in organic solar cells: the case of fluorinated PCPDTBT. J. Phys. Chem. Lett. 5, 1131–1138 (2014).
Ma, W. et al. Domain purity, miscibility, and molecular orientation at donor/acceptor interfaces in high performance organic solar cells: paths to further improvement. Adv. Energy Mater. 3, 864–872 (2013).
Mukherjee, S. et al. Importance of domain purity and molecular packing in efficient solution-processed small-molecule solar cells. Adv. Mater. 27, 1105–1111 (2015).
Collins, B. A. et al. Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films. Nature Mater. 11, 536–543 (2012).
Tumbleston, J. R. et al. The influence of molecular orientation on organic bulk heterojunction solar cells. Nature Photon. 8, 385–391 (2014).
Li, Z. et al. Dramatic performance enhancement for large bandgap thick-film polymer solar cells introduced by a difluorinated donor unit. Nano Energy 15, 607–615 (2015).
Ouyang, X., Peng, R., Ai, L., Zhang, X. & Ge, Z. Efficient polymer solar cells employing a non-conjugated small-molecule electrolyte. Nature Photon. 9, 520–524 (2015).
Lu, L., Xu, T., Chen, W., Landry, E. S. & Yu, L. Ternary blend polymer solar cells with enhanced power conversion efficiency. Nature Photon. 8, 716–722 (2014).
Nian, L. et al. Photoconductive cathode interlayer for highly efficient inverted polymer solar cells. J. Am. Chem. Soc. 137, 6995–6998 (2015).
Liao, S.-H. et al. Single junction inverted polymer solar cell reaching power conversion efficiency 10.31% by employing dual-doped zinc oxide nano-film as cathode interlayer. Sci. Rep. 4, 6813 (2014).
Hexemer, A. et al. A SAXS/WAXS/GISAXS beamline with multilayer monochromator. J. Phys. Conf. Ser. 247, 012007 (2010).
Rivnay, J., Noriega, R., Kline, R. J., Salleo, A. & Toney, M. F. Quantitative analysis of lattice disorder and crystallite size in organic semiconductor thin films. Phys. Rev. B 84, 045203 (2011).
Gann, E. et al. Soft X-ray scattering facility at the Advanced Light Source with real-time data processing and analysis. Rev. Sci. Instrum. 83, 045110 (2012).
The work was partially supported by the National Basic Research Program of China (973 Program; 2013CB834705), HK JEBN Limited (Hong Kong), the Hong Kong Research Grants Council (T23–407/13-N, N_HKUST623/13, and 606012), HKUST President’s Office through SSTSP scheme (project ref number: EP201) and the National Natural Science Foundation of China (NSFC, #21374090, 21504066, 21534003 and 51320105014). We thank Enli Technology Co., Ltd (Taiwan) for carrying out EQE measurements and Raynergy Tek Incorporation (Taiwan) for providing building blocks. H.A. is supported by ONR grants N000141410531 and N00141512322. X-ray data was acquired at beamlines 220.127.116.11 and 7.3.3 at the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under Contract No. DE-AC02-05CH11231.
The authors declare no competing financial interests.
About this article
Cite this article
Zhao, J., Li, Y., Yang, G. et al. Efficient organic solar cells processed from hydrocarbon solvents. Nat Energy 1, 15027 (2016). https://doi.org/10.1038/nenergy.2015.27
Nature Communications (2022)
Chinese Journal of Polymer Science (2022)
Science China Chemistry (2022)
Subtle Alignment of Organic Semiconductors at the Donor/Acceptor Heterojunction Facilitates the Photoelectric Conversion Process
Chinese Journal of Polymer Science (2022)