1 research outputs found
Small-Molecule Acceptor Based on the Heptacyclic Benzodi(cyclopentadithiophene) Unit for Highly Efficient Nonfullerene Organic Solar Cells
A new nonfullerene small molecule
with acceptor–donor–acceptor
(A–D–A) structure, namely, NFBDT, based on a heptacyclic
benzodiÂ(cyclopentadithiophene) (FBDT) unit using benzoÂ[1,2-<i>b</i>:4,5-<i>b</i>′]Âdithiophene as the core
unit, was designed and synthesized. Its absorption ability, energy
levels, thermal stability, as well as photovoltaic performances were
fully investigated. NFBDT exhibits a low optical bandgap of 1.56 eV
resulting in wide and efficient absorption that covered the range
from 600 to 800 nm, and suitable energy levels as an electron acceptor.
With the widely used and successful wide bandgap polymer PBDB-T selected
as the electron donor material, an optimized PCE of 10.42% was obtained
for the PBDB-T:NFBDT-based device with an outstanding short-circuit
current density of 17.85 mA cm<sup>–2</sup> under AM 1.5G irradiation
(100 mW cm<sup>–2</sup>), which is so far among the highest
performance of NF-OSC devices. These results demonstrate that the
BDT unit could also be applied for designing NF-acceptors, and the
fused-ring benzodiÂ(cyclopentadithiophene) unit is a prospective block
for designing new NF-acceptors with excellent performance