1. Molecular helices as electron acceptors in high-performance bulk heterojunction solar cells.
- Author
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Zhong Y, Trinh MT, Chen R, Purdum GE, Khlyabich PP, Sezen M, Oh S, Zhu H, Fowler B, Zhang B, Wang W, Nam CY, Sfeir MY, Black CT, Steigerwald ML, Loo YL, Ng F, Zhu XY, and Nuckolls C
- Subjects
- Electric Power Supplies, Imides chemistry, Microscopy, Atomic Force, Molecular Structure, Nanotechnology, Perylene chemistry, Perylene metabolism, Polymers chemistry, Spectrum Analysis, X-Ray Diffraction, Electrons, Imides metabolism, Perylene analogs & derivatives, Polymers metabolism, Semiconductors, Solar Energy
- Abstract
Despite numerous organic semiconducting materials synthesized for organic photovoltaics in the past decade, fullerenes are widely used as electron acceptors in highly efficient bulk-heterojunction solar cells. None of the non-fullerene bulk heterojunction solar cells have achieved efficiencies as high as fullerene-based solar cells. Design principles for fullerene-free acceptors remain unclear in the field. Here we report examples of helical molecular semiconductors as electron acceptors that are on par with fullerene derivatives in efficient solar cells. We achieved an 8.3% power conversion efficiency in a solar cell, which is a record high for non-fullerene bulk heterojunctions. Femtosecond transient absorption spectroscopy revealed both electron and hole transfer processes at the donor-acceptor interfaces. Atomic force microscopy reveals a mesh-like network of acceptors with pores that are tens of nanometres in diameter for efficient exciton separation and charge transport. This study describes a new motif for designing highly efficient acceptors for organic solar cells.
- Published
- 2015
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