Star-shaped small molecular donors based on a Zn-Porphyrin core and DPP arms via different linkers for organic solar cells

• Published in: Dyes and pigments Vol. 188; p. 109216
• Main Authors: Gao, Xuyu, Wu, Yijing, Song, Xiaochen, Tao, Xianwang, He, Yinming, Yang, Tianjian, Yu, Ruitao, Li, Zijing, Tao, Youtian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2021
• Subjects: Organic solar cells; Small-molecule donor; Spatial configuration; Star-shaped molecule; π-linkage; Star-shaped molecule; π-linkage; Organic solar cells; Small-molecule donor; Spatial configuration
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2021.109216

Star-shaped porphyrin-based small-molecule donors (SMDs) with all four-directional substitution have been rarely reported. Herein, we designed and synthesized two SMDs, namely ZnP-4PhDPP and ZnP-4ThDPP, by employing zinc porphyrin as the core, thiophene-capped diketopyrrolopyrrole (DPP) as the four conjugated arms via a phenyl or thienyl linking bridge. The varied linker resulted in differences in absorption, energy level and molecular geometry. Blended with Y6 as acceptor, all-small-molecule devices achieved power conversion efficiency (PCE) of 6.86% and 6.93% for ZnP-4PhDPP and ZnP-4ThDPP, upon different device post-treatment conditions, respectively. The more orthogonal spatial configuration of ZnP-4ThDPP was favorable for constructing additional charge pathways, which was in accord with the results from photoluminescence quenching efficiency, charge transport ability and thickness sensitivity evaluation. The results in this work enriched the category of star-shaped porphyrin-derivatives and might afford guidelines into the structure-property correlation of various linkers-based small-molecule photovoltaic materials.
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•Star-shaped small-molecule donors were constructed by porphyrin core and four DPP arms.•Phenyl or thienyl were employed as linkers to engender different spatial configurations.•~7% PCE was obtained from star-shaped porphyrin-based SMDs.•More orthogonal spatial configuration from thienyl linker induced better carrier dynamics than phenyl counterpart.