Improving the exciton dissociation of polymer/fullerene interfaces with a minimal loading amount of energy cascading molecular dopantElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ta03043j

In this work, a novel star-shaped conjugated small molecule, 2,2′,2′′-((benzo[1,2- b :3,4- b ′:5,6- b ′′]trithiophene-2,5,8-triyltris(3-(2-ethylhexyl)thiophene-5,2-diyl))tris(methanylylidene))trimalono-nitrile (BTTCN), with a benzotrithiophene donor unit as the core structure and the electron-withdr...

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Main Authors: Wang, Yang, Xu, Weidong, Yi, Jianpeng, Zuo, Chao, Gong, Yanting, Liu, Yuanyuan, Lai, Wen-Yong, Huang, Wei
Format: Article
Language:English
Online Access:Get full text
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Summary:In this work, a novel star-shaped conjugated small molecule, 2,2′,2′′-((benzo[1,2- b :3,4- b ′:5,6- b ′′]trithiophene-2,5,8-triyltris(3-(2-ethylhexyl)thiophene-5,2-diyl))tris(methanylylidene))trimalono-nitrile (BTTCN), with a benzotrithiophene donor unit as the core structure and the electron-withdrawing dicyano groups as the end-cappers, was designed and synthesized. It was used as the third component to construct ternary polymer solar cells (PSCs) based on a typical polymer/fullerene binary host (PTB7-Th:PC 71 BM). The results manifested that BTTCN served as an energy cascading interlayer to improve the exciton dissociation and transport of the active layer by doping with only a minimal amount of BTTCN that aided to construct a cascade energy level alignment. In contrast to the binary blends, the as-prepared PSCs with 3 wt% BTTCN dopant showed enhanced short-circuit current densities ( J SC ), which resulted in an enhanced power conversion efficiency (PCE) from 8.72% to 9.43%. Blending with a minimal loading amount of an energy cascading dopant has been explored to enhance the binary device performance effectively.
ISSN:2050-7488
2050-7496
DOI:10.1039/c8ta03043j