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Title: Molecular helices as electron acceptors in high-performance bulk heterojunction solar cells

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. As a result, this study describes a new motif for designing highly efficient acceptors for organic solar cells.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [1] ;  [1] ;  [2] ;  [4] ;  [2] ;  [2] ;  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Columbia Univ., New York, NY (United States)
  3. Columbia Univ., New York, NY (United States); Wuhan Univ. of Science and Technology, Wuhan (China)
  4. Princeton Univ., Princeton, NJ (United States)
Publication Date:
OSTI Identifier:
1235872
Report Number(s):
BNL--108124-2015-JA
Journal ID: ISSN 2041-1723; R&D Project: 16065/16074; KC0403020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal Issue: 01; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY chemical sciences; materials science; nanotechnology