Dong, Jingjin; Sami, Selim; Balazs, DanielISTA; Alessandri, Riccardo; Jahani, Fatimeh; Qiu, Li; Marrink, Siewert J.; Havenith, Remco W.A.; Hummelen, Jan C.; Loi, Maria A.; Portale, Giuseppe
For many years, fullerene derivatives have been the main n-type material of organic electronics and optoelectronics. Recently, fullerene derivatives functionalized with ethylene glycol (EG) side chains have been showing important properties such as enhanced dielectric constants, facile doping and enhanced self-assembly capabilities. Here, we have prepared field-effect transistors using a series of these fullerene derivatives equipped with EG side chains of different lengths. Transport data show the beneficial effect of increasing the EG side chain. In order to understand the material properties, full structural determination of these fullerene derivatives has been achieved by coupling the X-ray data with molecular dynamics (MD) simulations. The increase in transport properties is paired with the formation of extended layered structures, efficient molecular packing and an increase in the crystallite alignment. The layer-like structure is composed of conducting layers, containing of closely packed C60 balls approaching the inter-distance of 1 nm, that are separated by well-defined EG layers, where the EG chains are rather splayed with the chain direction almost perpendicular to the layer normal. Such a layered structure appears highly ordered and highly aligned with the C60 planes oriented parallel to the substrate in the thin film configuration. The order inside the thin film increases with the EG chain length, allowing the systems to achieve mobilities as high as 0.053 cm2 V−1 s−1. Our work elucidates the structure of these interesting semiconducting organic molecules and shows that the synergistic use of X-ray structural analysis and MD simulations is a powerful tool to identify the structure of thin organic films for optoelectronic applications.
Journal of Materials Chemistry C
J. D. gratefully acknowledges the China Scholarship Council (CSC No. 201606340158) for supporting his PhD studies. S. S. thanks J. Antoja-Lleonart for insightful discussions on simulating the X-ray diffraction patterns. Part of the work was sponsored by NWO Exact and Natural Sciences for the use of supercomputer facilities (Contract no. 17197 7095). Regarding S. S., R. A., R. W. A. H., J. C. H., and M. A. L., this is a publication by the FOM Focus Group “Next Generation Organic Photovoltaics”, participating in the Dutch Institute for Fundamental Energy Research (DIFFER). The ESRF is acknowledged for providing the beamtime. J. D. and G. P. are grateful to the BM26B staff for their great support during the beamtime. M. A. L., D. M. B. are grateful for the financial support of the European Research Council via a Starting Grant (HySPOD, No. 306983).
Dong J, Sami S, Balazs D, et al. Fullerene derivatives with oligoethylene-glycol side chains: An investigation on the origin of their outstanding transport properties. Journal of Materials Chemistry C. 2021;9(45):16217-16225. doi:10.1039/d1tc02753k
Dong, J., Sami, S., Balazs, D., Alessandri, R., Jahani, F., Qiu, L., … Portale, G. (2021). Fullerene derivatives with oligoethylene-glycol side chains: An investigation on the origin of their outstanding transport properties. Journal of Materials Chemistry C. https://doi.org/10.1039/d1tc02753k
Dong, Jingjin, Selim Sami, Daniel Balazs, Riccardo Alessandri, Fatimeh Jahani, Li Qiu, Siewert J. Marrink, et al. “Fullerene Derivatives with Oligoethylene-Glycol Side Chains: An Investigation on the Origin of Their Outstanding Transport Properties.” Journal of Materials Chemistry C, 2021. https://doi.org/10.1039/d1tc02753k.
J. Dong et al., “Fullerene derivatives with oligoethylene-glycol side chains: An investigation on the origin of their outstanding transport properties,” Journal of Materials Chemistry C, vol. 9, no. 45. pp. 16217–16225, 2021.
Dong J, Sami S, Balazs D, Alessandri R, Jahani F, Qiu L, Marrink SJ, Havenith RWA, Hummelen JC, Loi MA, Portale G. 2021. Fullerene derivatives with oligoethylene-glycol side chains: An investigation on the origin of their outstanding transport properties. Journal of Materials Chemistry C. 9(45), 16217–16225.
Dong, Jingjin, et al. “Fullerene Derivatives with Oligoethylene-Glycol Side Chains: An Investigation on the Origin of Their Outstanding Transport Properties.” Journal of Materials Chemistry C, vol. 9, no. 45, 2021, pp. 16217–25, doi:10.1039/d1tc02753k.
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