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Tuning the molecular packing and energy levels of fullerene acceptors for polymer solar cells
Fullerenes are considered to be promising acceptor materials for the fabrication of bulk-heterojunction polymer solar cells (PSCs) due to their excellent physical and chemical properties. Herein, two novel fullerene derivatives with different specific functional groups, 2-benzylthiophene-C 60 bis-ad...
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Published in: | Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2019, Vol.7 (4), p.12688-12694 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Fullerenes are considered to be promising acceptor materials for the fabrication of bulk-heterojunction polymer solar cells (PSCs) due to their excellent physical and chemical properties. Herein, two novel fullerene derivatives with different specific functional groups, 2-benzylthiophene-C
60
bis-adduct (
BTCBA
) and 2-(4-methoxybenzyl)thiophene-C
60
bis-adduct (
MBTCBA
), were synthesized and utilized as acceptors for PSCs with the purpose of investigating the influence of the fullerene derivative substituents on the device performance. Compared with
BTCBA
,
MBTCBA
exhibits a higher lowest unoccupied molecular orbital (LUMO) energy level due to the electron donating properties of the 2-(4-methoxybenzyl)thiophene functional group. Meanwhile, the appropriate intermolecular interaction of
MBTCBA
molecules promotes the favorable nanophase separation of the P3HT/
MBTCBA
based blending film, resulting in a higher electron mobility. Therefore, PSCs incorporating P3HT as a donor and
MBTCBA
as an acceptor yield a power conversion efficiency (PCE) of 5.29% with an open-circuit voltage (
V
OC
) of 0.81 V, which is obviously higher than those of
BTCBA
(3.54%) and
PCBM
(3.76%) based devices. Our work proves that the PSC performance can be readily improved by modification of fullerene acceptors using an electron donating group, tuning the LUMO energy level and the molecular packing behavior.
Two novel fullerene acceptors were synthesized and applied in polymer solar cells, and the importance of functional groups in tuning the molecular packing and energy levels for the design of fullerene acceptors was demonstrated. |
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ISSN: | 2050-7526 2050-7534 |
DOI: | 10.1039/c9tc04111g |