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Side-chain engineering of high-efficiency conjugated polymer photovoltaic materials

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  • ReceivedSep 1, 2014
  • AcceptedSep 19, 2014
  • PublishedJan 22, 2015

Abstract

In recent years, conjugated polymers have attracted great attention in the application as photovoltaic donor materials in polymer solar cells (PSCs). Broad absorption, lower-energy bandgap, higher hole mobility, relatively lower HOMO energy levels, and higher solubility are important for the conjugated polymer donor materials to achieve high photovoltaic performance. Side-chain engineering plays a very important role in optimizing the physicochemical properties of the conjugated polymers. In this article, we review recent progress on the side-chain engineering of conjugated polymer donor materials, including the optimization of flexible side-chains for balancing solubility and intermolecular packing (aggregation), electron-withdrawing substituents for lowering HOMO energy levels, and two-dimension (2D)-conjugated polymers with conjugated side-chains for broadening absorption and enhancing hole mobility. After the molecular structural optimization by side-chain engineering, the 2D-conjugated polymers based on benzodithiophene units demonstrated the best photovoltaic performance, with power- conversion efficiency higher than 9%.


Acknowledgment

This work was supported by the National Basic Research Program of China (2014CB643501) and the National Natural Science Foundation of China (91433117, 91333204 and 21374124).


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