Following the development of the bulk heterojunction1 structure, recent years have seen a dramatic improvement in the efficiency of polymer solar cells. Maximizing the open-circuit voltage in a low-bandgap polymer is one of the critical factors towards enabling high-efficiency solar cells. Study of the relation between open-circuit voltage and the energy levels of the donor/acceptor2 in bulk heterojunction polymer solar cells has stimulated interest in modifying the open-circuit voltage by tuning the energy levels of polymers3. Here, we show that the open-circuit voltage of polymer solar cells constructed based on the structure of a low-bandgap polymer, PBDTTT4, can be tuned, step by step, using different functional groups, to achieve values as high as 0.76 V. This increased open-circuit voltage combined with a high short-circuit current density results in a polymer solar cell with a power conversion efficiency as high as 6.77%, as certified by the National Renewable Energy Laboratory.
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Sariciftci, N. S., Smilowitz, L., Heeger, A. J. & Wudl, F. Photoinduced electron-transfer from a conducting polymer to buckminsterfullerene. Science 258, 1474–1476 (1992).
Brabec, C. J. et al. Origin of the open circuit voltage of plastic solar cells. Adv. Funct. Mater. 11, 374–380 (2001).
Hou, J. H. et al. Bandgap and molecular energy level control of conjugated polymer photovoltaic materials based on benzo[1,2-b:4,5-b']dithiophene. Macromolecules 41, 6012–6018 (2008).
Liang, Y. Y. et al. Development of new semiconducting polymers for high performance solar cells. J. Am. Chem. Soc. 131, 56–57 (2009).
Hoth, C. N., Choulis, S. A., Schilinsky, P. & Brabec, C. J. High photovoltaic performance of inkjet printed polymer: fullerene blends. Adv. Mater. 19, 3973–3978 (2007).
Aernouts, T., Aleksandrov, T., Girotto, C., Genoe, J. & Poortmans, J. Polymer based organic solar cells using ink-jet printed active layers. Appl. Phys. Lett. 92, 033306 (2008).
Pudas, M., Hagberg, J. & Leppavuori, S. Gravure offset printing of polymer inks for conductors. Progr. Org. Coatings 49, 324–335 (2004).
Krebs, F. C., Gevorgyan, S. A. & Alstrup, J. A roll-to-roll process to flexible polymer solar cells: model studies, manufacture and operational stability studies. J. Mater. Chem. 19, 5442–5451 (2009).
Krebs, F. C. Fabrication and processing of polymer solar cells: a review of printing and coating techniques. Sol. Eng. Mater. Sol. Cells 93, 394–412 (2009).
Li, G. et al. High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends. Nature Mater. 4, 864–868 (2005).
Ma, W. L., Yang, C. Y., Gong, X., Lee, K. & Heeger, A. J. Thermally stable, efficient polymer solar cells with nanoscale control of the interpenetrating network morphology. Adv. Funct. Mater. 15, 1617–1622 (2005).
Padinger, F., Rittberger, R. S. & Sariciftci, N. S. Effects of postproduction treatment on plastic solar cells. Adv. Funct. Mater. 13, 85–88 (2003).
Li, G., Shrotriya, V., Yao, Y. & Yang, Y. Investigation of annealing effects and film thickness dependence of polymer solar cells based on poly(3-hexylthiophene). J. Appl. Phys. 98, 043704 (2005).
Zhang, F. L. et al. Influence of solvent mixing on the morphology and performance of solar cells based on polyfluorene copolymer/fullerene blends. Adv. Funct. Mater. 16, 667–674 (2006).
Peet, J. et al. Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols. Nature Mater. 6, 497–500 (2007).
Chen, C. P., Chan, S. H., Chao, T. C., Ting, C. & Ko, B. T. Low-bandgap poly(thiophene–phenylene–thiophene) derivatives with broaden absorption spectra for use in high-performance bulk-heterojunction polymer solar cells. J. Am. Chem. Soc. 130, 12828–12833 (2008).
Blouin, N., Michaud, A. & Leclerc, M. A low-bandgap poly(2,7-carbazole) derivative for use in high-performance solar cells. Adv. Mater. 19, 2295–2300 (2007).
Gadisa, A. et al. A new donor–acceptor–donor polyfluorene copolymer with balanced electron and hole mobility. Adv. Funct. Mater. 17, 3836–3842 (2007).
Park, S. H. et al. Bulk heterojunction solar cells with internal quantum efficiency approaching 100%. Nature Photon. 3, 297–303 (2009).
Chen, M. H. et al. Efficient polymer solar cells with thin active layers based on alternating polyfluorene copolymer/fullerene bulk heterojunctions. Adv. Mater. 21, 1–5 (2009).
Hou, J., Chen, H.-Y., Zhang, S., Li, G. & Yang, Y. Synthesis, characterization and photovoltaic properties of a low bandgap polymer based on silole-containing polythiophenes and benzo[c][1,2,5]thiadiazole. J. Am. Chem. Soc. 130, 16144–16145 (2008).
Wang, E. et al. High-performance polymer heterojunction solar cells of a polysilafluorene derivative. Appl. Phys. Lett. 92, 033307 (2008).
Krebs, F. C. et al. A complete process for production of flexible large area polymer solar cells entirely using screen printing—first public demonstration. Sol. Eng. Mater. Sol. Cells 93, 422–441 (2009).
Scharber, M. C. et al. Design rules for donors in bulk-heterojunction solar cells—towards 10% energy-conversion efficiency. Adv. Mater. 18, 789–794 (2006).
Shi, C. J., Yao, Y., Yang, Y. & Pei, Q. B. Regioregular copolymers of 3-alkoxythiophene and their photovoltaic application. J. Am. Chem. Soc. 128, 8980–8986 (2006).
Liang, Y. Y. et al. Highly efficient solar cell polymers developed via fine-tuning of structural and electronic properties. J. Am. Chem. Soc. 131, 7792–7799 (2009).
Jorgensen, M., Norrman, K. & Krebs, F. C. Stability/degradation of polymer solar cells. Sol. Eng. Mater. Sol. Cells 92, 686–714 (2008).
Shrotriya, V., Wu, E. H. E., Li, G., Yao, Y. & Yang, Y. Efficient light harvesting in multiple-device stacked structure for polymer solar cells. Appl. Phys. Lett. 88, 064104 (2006).
Shrotriya, V., Yao, Y., Li, G. & Yang, Y. Effect of self-organization in polymer/fullerene bulk heterojunctions on solar cell performance. Appl. Phys. Lett. 89, 063505 (2006).
Li, G. et al. ‘Solvent annealing’ effect in polymer solar cells based on poly(3-hexylthiophene) and methanofullerenes. Adv. Funct. Mater. 17, 1636–1644 (2007).
Li, G., Shrotriya, V., Yao, Y., Huang, J. S. & Yang, Y. Manipulating regioregular poly(3-hexylthiophene): [6,6]-phenyl-C-61-butyric acid methyl ester blends—route towards high efficiency polymer solar cells. J. Mater. Chem. 17, 3126–3140 (2007).
Chu, C. W. et al. Control of the nanoscale crystallinity and phase separation in polymer solar cells. Appl. Phys. Lett. 92, 103306 (2008).
The National Renewable Energy Laboratory (NREL) is thanked for conducting the certification of devices. The authors in particular thank D.C. Olson at NREL for his help in verifying and certifying the performances of our devices.
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Chen, HY., Hou, J., Zhang, S. et al. Polymer solar cells with enhanced open-circuit voltage and efficiency. Nature Photon 3, 649–653 (2009). https://doi.org/10.1038/nphoton.2009.192
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