Harmonious Compatibility Dominates Influence of Side‐Chain Engineering on Morphology and Performance of Ternary Solar Cells. Issue 22 (28th May 2018)

• Record Type: Journal Article
• Authors: Kumari, Tanya; Lee, Sang Myeon; Lee, Kyu Cheol; Cho, Yongjoon; Yang, Changduk
• Is Part Of: Advanced energy materials. Volume 8:Issue 22(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-05-28
• Subjects: alloy‐like structures -- side chains -- small molecule donors -- structure–property relationships -- ternary solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201800616
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: 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‐C71 ‐butyric acid methyl ester (PTB7‐Th:PC71 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. Abstract : Harmonious compatibility between the polymer and small molecule donors (SMDs) with different terminal side‐chain lengths leads to a similar high power conversion efficiency of 12.0–12.2% in ternary solar cells in contrast to the binary systems with SMDs, where the performance depends on side‐chain length, offering a new guideline for pairing donor components for accomplishing high‐performance ternary solar cells.