A design strategy for intramolecular singlet fission mediated by charge-transfer states in donor–acceptor organic materials
Source abstract
Abstract
The ability to advance our understanding of multiple exciton generation (MEG) in organic materials has been restricted by the limited number of materials capable of singlet fission. A particular challenge is the development of materials that undergo efficient intramolecular fission, such that local order and strong nearest-neighbour coupling is no longer a design constraint. Here we address these challenges by demonstrating that strong intrachain donor-acceptor interactions are a key design feature for organic materials capable of intramolecular singlet fission. By conjugating strong-acceptor and strong-donor building blocks, small molecules and polymers with charge-transfer states that mediate population transfer between singlet excitons and triplet excitons are synthesized. Using transient optical techniques, we show that triplet populations can be generated with yields up to 170%. These guidelines are widely applicable to similar families of polymers and small molecules, and can lead to the development of new fission-capable materials with tunable electronic structure, as well as a deeper fundamental understanding of MEG.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Organic Electronics and Photovoltaics · Perovskite Materials and Applications · Conducting polymers and applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (47)
Show source-provided references
1. 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).10.1126/science.270.5243.1789 ↗
2. Tang, C. W. Two-layer organic photovoltaic cell. Appl. Phys. Lett. 48, 183–185 (1986).10.1063/1.96937 ↗
3. Gélinas, S. et al. Ultrafast long-range charge separation in organic semiconductor photovoltaic diodes. Science 343, 512–516 (2014).10.1126/science.1246249 ↗
4. Brédas, J-L., Norton, J. E., Cornil, J. & Coropceanu, V. Molecular understanding of organic solar cells: The challenges. Acc. Chem. Res. 42, 1691–1699 (2009).10.1021/ar900099h ↗
5. Erb, T. et al. Correlation between structural and optical properties of composite polymer/fullerene films for organic solar cells. Adv. Funct. Mater. 15, 1193–1196 (2005).10.1002/adfm.200400521 ↗
6. Kim, J. Y. et al. Efficient tandem polymer solar cells fabricated by all-solution processing. Science 317, 222–225 (2007).10.1126/science.1141711 ↗
7. You, J. et al. A polymer tandem solar cell with 10.6% power conversion efficiency. Nature Commun. 4, 1446 (2013).10.1038/ncomms2411 ↗
8. Small, C. E. et al. High-efficiency inverted dithienogermole-thienopyrrolodione-based polymer solar cells. Nature Photon. 6, 115–120 (2012).10.1038/nphoton.2011.317 ↗
9. Sun, Y. et al. Solution-processed small-molecule solar cells with 6.7% efficiency. Nature Mater. 11, 44–48 (2012).10.1038/nmat3160 ↗
10. Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p–n junction solar cells. J. Appl. Phys. 32, 510–519 (1961).10.1063/1.1736034 ↗
11. Hanna, M. C. & Nozik, A. J. Solar conversion efficiency of photovoltaic and photoelectrolysis cells with carrier multiplication absorbers. J. Appl. Phys. 100, 074510 (2006).10.1063/1.2356795 ↗
12. Ehrler, B. et al. In situ measurement of exciton energy in hybrid singlet-fission solar cells. Nature Commun. 3, 1019 (2012).10.1038/ncomms2012 ↗
13. Tritsch, J. R., Chan, W-L., Wu, X., Monahan, N. R. & Zhu, X. Y. Harvesting singlet fission for solar energy conversion via triplet energy transfer. Nature Commun. 4, 2679 (2013).
14. Congreve, D. N. et al. External quantum efficiency above 100% in a singlet-exciton-fission–based organic photovoltaic cell. Science 340, 334–337 (2013).10.1126/science.1232994 ↗
15. Johnson, J. C., Nozik, A. J. & Michl, J. The role of chromophore coupling in singlet fission. Acc. Chem. Res. 46, 1290–1299 (2013).10.1021/ar300193r ↗
16. Smith, M. B. & Michl, J. Singlet fission. Chem. Rev. 110, 6891–6936 (2010).10.1021/cr1002613 ↗
17. Roberts, S. T. et al. Efficient singlet fission discovered in a disordered acene film. J. Am. Chem. Soc. 134, 6388–6400 (2012).10.1021/ja300504t ↗
18. Yost, S. R. et al. A transferable model for singlet fission kinetics. Nature Chem. 6, 492–497 (2014).10.1038/nchem.1945 ↗
19. Antognazza, M. R. et al. Ultrafast excited state relaxation in long-chain polyenes. Chem. Phys. 373, 115–121 (2010).10.1016/j.chemphys.2010.03.002 ↗
20. Kraabel, B., Hulin, D., Aslangul, C., Lapersonne-Meyer, C. & Schott, M. Triplet exciton generation, transport and relaxation in isolated polydiacetylene chains: Subpicosecond pump-probe experiments. Chem. Phys. 227, 83–98 (1998).10.1016/S0301-0104(97)00200-0 ↗
21. Musser, A. J. et al. Activated singlet exciton fission in a semiconducting polymer. J. Am. Chem. Soc. 135, 12747–12754 (2013).10.1021/ja405427j ↗
22. Gradinaru, C. C. et al. An unusual pathway of excitation energy deactivation in carotenoids: Singlet-to-triplet conversion on an ultrafast timescale in a photosynthetic antenna. Proc. Natl Acad. Sci. USA 98, 2364–2369 (2001).10.1073/pnas.051501298 ↗
23. Papagiannakis, E. et al. Light harvesting by carotenoids incorporated into the B850 light-harvesting complex from rhodobacter sphaeroides R-26.1: Excited-state relaxation, ultrafast triplet formation, and energy transfer to bacteriochlorophyll. J. Phys. Chem. B 107, 5642–5649 (2003).10.1021/jp027174i ↗
24. Johnson, J. C. et al. Toward designed singlet fission: Solution photophysics of two indirectly coupled covalent dimers of 1,3-diphenylisobenzofuran. J. Phys. Chem. B 117, 4680–4695 (2013).10.1021/jp310979q ↗
25. Dell, E. J. & Campos, L. M. The preparation of thiophene-S, S-dioxides and their role in organic electronics. J. Mater. Chem. 22, 12945–12952 (2012).10.1039/c2jm31220d ↗
26. Wei, S. et al. Bandgap engineering through controlled oxidation of polythiophenes. Angew. Chem. Int. Ed. 53, 1832–1836 (2014).10.1002/anie.201309398 ↗
27. Beljonne, D., Yamagata, H., Brédas, J., Spano, F. & Olivier, Y. Charge-transfer excitations steer the Davydov splitting and mediate singlet exciton fission in pentacene. Phys. Rev. Lett. 110, 226402 (2013).10.1103/PhysRevLett.110.226402 ↗
28. Berkelbach, T. C., Hybertsen, M. S. & Reichman, D. R. Microscopic theory of singlet exciton fission. I. General formulation. J. Chem. Phys. 138, 114102 (2013).10.1063/1.4794425 ↗
29. Berkelbach, T. C., Hybertsen, M. S. & Reichman, D. R. Microscopic theory of singlet exciton fission II. Application to pentacene dimers and the role of superexchange. J. Chem. Phys. 138, 114103 (2013).10.1063/1.4794427 ↗
30. Chan, W-L. et al. The quantum coherent mechanism for singlet fission: Experiment and theory. Acc. Chem. Res. 46, 1321–1329 (2013).10.1021/ar300286s ↗
31. Chan, W-L. et al. Observing the multiexciton state in singlet fission and ensuing ultrafast multielectron transfer. Science 334, 1541–1545 (2011).10.1126/science.1213986 ↗
32. Chan, W-L., Ligges, M. & Zhu, X. Y. The energy barrier in singlet fission can be overcome through coherent coupling and entropic gain. Nature Chem. 4, 840–845 (2012).10.1038/nchem.1436 ↗
33. Sharifzadeh, S., Darancet, P., Kronik, L. & Neaton, J. B. Low-energy charge-transfer excitons in organic solids from first-principles: The case of pentacene. J. Phys. Chem. Lett. 4, 2197–2201 (2013).10.1021/jz401069f ↗
34. Zhou, H., Yang, L. & You, W. Rational design of high performance conjugated polymers for organic solar cells. Macromolecules 45, 607–632 (2012).10.1021/ma201648t ↗
35. Kitamura, C., Tanaka, S. & Yamashita, Y. Design of narrow-bandgap polymers. Syntheses and properties of monomers and polymers containing aromatic-donor and o-quinoid-acceptor units. Chem. Mater. 8, 570–578 (1996).10.1021/cm950467m ↗
36. Brédas, J. Relationship between band gap and bond length alternation in organic conjugated polymers. J. Chem. Phys. 82, 3808–3811 (1985).10.1063/1.448868 ↗
37. Havinga, E., Ten Hoeve, W. & Wynberg, H. A new class of small band gap organic polymer conductors. Polym. Bull. 29, 119–126 (1992).10.1007/BF00558045 ↗
38. Szarko, J. M. et al. Electronic processes in conjugated diblock oligomers mimicking low band-gap polymers. Experimental and theoretical spectral analysis. J. Phys. Chem. B 114, 14505–14513 (2010).10.1021/jp101925b ↗
39. Guo, J., Ohkita, H., Benten, H. & Ito, S. Near-IR femtosecond transient absorption spectroscopy of ultrafast polaron and triplet exciton formation in polythiophene films with different regioregularities. J. Am. Chem. Soc. 131, 16869–16880 (2009).10.1021/ja906621a ↗
40. Mullen, K. M., Vengris, M. & van Stokkum, I. H. Algorithms for separable nonlinear least squares with application to modelling time-resolved spectra. J. Glob. Optim. 38, 201–213 (2007).10.1007/s10898-006-9071-7 ↗
41. Van Stokkum, I. H., Larsen, D. S. & van Grondelle, R. Global and target analysis of time-resolved spectra. Biochim. Biophys. Acta 1657, 82–104 (2004).10.1016/j.bbabio.2004.04.011 ↗
42. Wishart, J. F., Cook, A. R. & Miller, J. R. The LEAF Picosecond Pulse Radiolysis Facility at Brookhaven National Laboratory. Rev. Sci. Instrum. 75, 4359–4366 (2004).10.1063/1.1807004 ↗
43. Head-Gordon, M., Grana, A. M., Maurice, D. & White, C. A. Analysis of electronic transitions as the difference of electron attachment and detachment densities. J. Phys. Chem. 99, 14261–14270 (1995).10.1021/j100039a012 ↗
44. Oliva, M. M. et al. Do [all]-S, S′-dioxide oligothiophenes show electronic and optical properties of oligoenes and/or of oligothiophenes? J. Am. Chem. Soc. 132, 6231–6242 (2010).10.1021/ja101015q ↗
45. Amir, E. et al. Synthesis and characterization of soluble low-bandgap oligothiophene-[all]-S, S-dioxides-based conjugated oligomers and polymers. J. Polym. Sci. A 49, 1933–1941 (2011).10.1002/pola.24641 ↗
46. Sreearunothai, P. et al. Triplet transport to and trapping by acceptor end groups on conjugated polyfluorene chains. J. Phys. Chem. C 115, 19569–19577 (2011).10.1021/jp205828q ↗
47. Heinzelmann, W. & Labhart, H. Triplet–triplet spectra and triplet quantum yields of some aromatic hydrocarbons in liquid solution. Chem. Phys. Lett. 4, 20–24 (1969).10.1016/0009-2614(69)85023-2 ↗