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Efficient polymer solar cells employing a non-conjugated small-molecule electrolyte

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Abstract

Polymer solar cells have drawn a great deal of attention due to the attractiveness of their use in renewable energy sources that are potentially lightweight and low in cost. Recently, numerous significant research efforts have resulted in polymer solar cells with power conversion efficiencies in excess of 9% (ref. 1). Nevertheless, further improvements in performance are sought for commercial applications. Here, we report polymer solar cells with a power conversion efficiency of 10.02% that employ a non-conjugated small-molecule electrolyte as an interlayer. The material offers good contact for photogenerated charge carrier collection and allows optimum photon harvesting in the device. Furthermore, the enhanced performance is attributed to improved electron mobility, enhanced active-layer absorption and properly active-layer microstructures with optimal horizontal phase separation and vertical phase gradation. Our discovery opens a new avenue for single-junction devices by fully exploiting the potential of various material systems with efficiency over 10%.

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Figure 1: Device structures and energy levels of PSCs.
Figure 2: Device performance of the conventional structure ITO/PEDOT:PSS/PTB7:PC71BM/MSAPBS interlayer/Al.
Figure 3: Tapping-mode AFM topography images and three-dimensional surface plots.
Figure 4: Measured JV curves for electron-only devices.

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Acknowledgements

This work was supported financially by the National Natural Science Foundation of China (51273209, 5141140244), Ningbo International Cooperation Foundation (2012D10009, 2013D10013), Ningbo Natural Science Foundation (2014A610126), the Open Fund of the State Key Laboratory of Luminescent Materials and Devices and the External Cooperation Program of the Chinese Academy of Sciences (no. GJHZ1219).

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X.O. and Z.G. conceived the idea and designed the experiments. R.P. fabricated and characterized the devices. X.O., X.Z. and L.A. carried out the optical and electron measurements. X.O. synthesized the interlayer material. Z.G. coordinated and directed the study. All authors contributed to manuscript preparation, data analysis and interpretation, and discussed the results. X.O. and R.P. contributed equally to the present study.

Corresponding author

Correspondence to Ziyi Ge.

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The authors declare no competing financial interests.

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Ouyang, X., Peng, R., Ai, L. et al. Efficient polymer solar cells employing a non-conjugated small-molecule electrolyte. Nature Photon 9, 520–524 (2015). https://doi.org/10.1038/nphoton.2015.126

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