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Harmonious Compatibility Dominates Influence of Side‐Chain Engineering on Morphology and Performance of Ternary Solar Cells
Author(s) -
Kumari Tanya,
Lee Sang Myeon,
Lee Kyu Cheol,
Cho Yongjoon,
Yang Changduk
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800616
Subject(s) - ternary operation , materials science , organic solar cell , side chain , compatibility (geochemistry) , molecule , chemical engineering , energy conversion efficiency , polymer chemistry , polymer , organic chemistry , composite material , optoelectronics , chemistry , computer science , engineering , programming language
A growing number of recent studies have demonstrated the substantial impact of the alkyl side chains on the device performance of organic semiconductors. However, detailed investigation of the effect of side‐chain engineering on the blend morphology and performance of ternary organic solar cells (OSCs) has not yet been undertaken. In this study, the performance of ternary OSCs is investigated in a given poly(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐ b ;4,5‐ b ′]dithiophene‐2,6‐diyl‐ alt ‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐ b ]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)):[6,6]‐phenyl‐C 71 ‐butyric acid methyl ester (PTB7‐Th:PC 71 BM) host set by introducing various small molecule donors (SMDs) with different terminal side‐chain lengths. As expected, the performance of binary OSCs with SMDs depends greatly on the side‐chain length. In contrast, it is observed that all SMD‐based ternary OSCs exhibit almost identical and high power‐conversion efficiencies of 12.0–12.2%. This minor performance variation is attributed to good molecular compatibility between the two donor components, as evidenced by in‐depth electrical and morphological investigations. These results highlight that the alloy‐like structure formed due to the high compatibility of the donor molecules has a more significant effect on the overall performance than the side‐chain length, offering a new guideline for pairing donor components for achieving high‐performance ternary OSCs.