Fullerenes and their derivatives are widely used as electron acceptors in bulk-heterojunction organic solar cells as they combine high electron mobility with good solubility and miscibility with relevant semiconducting polymers. However, studies on the use of fullerenes as the sole photogeneration and charge-carrier material are scarce. Here, a new type of solution-processed small-molecule solar cell based on the two most commonly used methanofullerenes, namely [6,6]-phenyl-C61-butyric acid methyl ester (PC60BM) and [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM), as the light absorbing materials, is reported. First, it is shown that both fullerene derivatives exhibit excellent ambipolar charge transport with balanced hole and electron mobilities. When the two derivatives are spin-coated over the wide bandgap p-type semiconductor copper (I) thiocyanate (CuSCN), cells with power conversion efficiency (PCE) of ≈1%, are obtained. Blending the CuSCN with PC70BM is shown to increase the performance further yielding cells with an open-circuit voltage of ≈0.93 V and a PCE of 5.4%. Microstructural analysis reveals that the key to this success is the spontaneous formation of a unique mesostructured p–n-like heterointerface between CuSCN and PC70BM. The findings pave the way to an exciting new class of single photoactive material based solar cells.
Bibliographical noteFunding Information:
W.-Y.S. and F.E. contributed equally to this work. The work reported here was supported by the King Abdullah University of Science and Technology (KAUST). C.B. and M.A.M. gratefully acknowledge the EPSRC Doctoral Prize Fellowship (ICL) for the financial support. G.V. and F.G. acknowledge Graphene Flagship (Horizon 2020 Grant No. 696656 – GrapheneCore1) for the financial support. G.V. and F.G. also acknowledge the DECI resource “Cartesius” based in The Netherlands at SURFsara and “Abel” based in Oslo with support from the PRACE AISBL.
© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- copper (I) thiocyanate
- mesostructured heterointerfaces
- solar cells
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Chemical Engineering(all)
- Materials Science(all)
- Biochemistry, Genetics and Molecular Biology (miscellaneous)
- Physics and Astronomy(all)