Rhodanine-Bridged Core-Expanded Naphthalene Diimide Derivatives for n-Type Semiconductors

• Published in: Organic Materials Vol. 2; no. 2; pp. 165 - 172
• Main Authors: Li, Jiangao, Li, Jing, Ge, Congwu, Gao, Xike
• Format: Journal Article
• Language: English
• Published: Rüdigerstraße 14, 70469 Stuttgart, Germany Georg Thieme Verlag KG 01.04.2020; Georg Thieme Verlag
• Subjects: electron transport materials; naphthalene diimides; organic semiconductors; organic thin-film transistors; Original Article; rhodanine; organic semiconductors; organic thin-film transistors; electron transport materials; rhodanine; naphthalene diimides
• ISSN: 2625-1825; 2625-1825
• DOI: 10.1055/s-0040-1710550

Abstract The core expansion of naphthalene diimides (NDIs) is an effective strategy to modulate frontier molecular orbital energy levels and improve device performances. Herein two new rhodanine-bridged and core-extended NDIs T1 and T2 were designed and synthesized. The rhodanine moiety could act not only as a π-spacer to enlarge the molecular conjugated system, but also as an electron-donating unit to tune the molecular energy levels. As a result, both T1 and T2 showed slightly lower lying LUMO energy levels (< − 4.2 eV) by ca . 0.1 eV and narrower optical band gaps ( ca. 1.5 eV) by 0.5 eV compared to those of n-type organic semiconductor (OSC) NDI2DT-DTYM2.The solution-processed organic thin-film transistors based on T1 and T2 exhibited electron motilities in the range of 10 −4 –10 −3 cm 2 V −1 s −1 , and the inverted perovskite solar cells constructed using T2 as electron transport materials provided a power conversion efficiency value of 8.82%. The results demonstrated that embedding rhodanine units in a NDI2DT-DTYM2 backbone is an effective approach to tune the energy levels and optical properties of OSCs, providing a new way to construct novel n-type OSCs with multifunctional optoelectronic applications.