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Designing Alternative Non‐Fullerene Molecular Electron Acceptors for Solution‐Processable Organic Photovoltaics
Author(s) -
Sauvé Geneviève
Publication year - 2019
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.201800157
Subject(s) - fullerene , organic solar cell , materials science , conjugated system , nanotechnology , miscibility , homoleptic , polymer , chemical engineering , chemistry , organic chemistry , composite material , metal , metallurgy , engineering
Until recently, solution‐processable organic photovoltaics (OPVs) mainly relied on fullerene derivatives as the n ‐type material, paired with a p ‐type conjugated polymer. However, fullerene derivatives have disadvantages that limit OPV performance, thus fueling research of non‐fullerene acceptors (NFAs). Initially, NFAs showed poor performance due to difficulties in obtaining favorable blend morphologies. One example is our work with 2,6‐dialkylamino core‐substituted naphthalene diimides. Researchers then learned to control blend morphology by NFA molecular design. To limit miscibility with polymer while preventing excessive self‐aggregation, non‐planar, twisted or 3D structures were reported. An example of a 3D structure is our work with homoleptic zinc(II) complexes of azadipyrromethene. The most recent design is a planar A‐D‐A conjugated system where the D unit is rigid and has orthogonal side chains to control aggregation. These have propelled power conversion efficiencies (PCEs) to ∼14 %, surpassing fullerene‐based OPVs. These exciting new developments prompt further investigations of NFAs and provide a bright future for OPVs.