Developing Wide Bandgap Polymers Based on Sole Benzodithiophene Units for Efficient Polymer Solar Cells

Xiaopeng Xu, Young Woong Lee, Han Young Woo, Ying Li, Qiang Peng

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

In this work, a series of sole benzodithiophene-based wide band gap polymer donors, namely PBDTT, PBDTS, PBDTF and PBDTCl, were developed for efficient polymer solar cells (PSCs) by varying the heteroatoms into the conjugated side chains. The effects of sulfuration, fluorination and chlorination were also investigated systematically on the overall properties of these BDT-based polymers. The HOMO levels could be lowered gradually by introducing sulfur, fluorine and chlorine atoms into the side chains, which contributed to the stepwise increased Voc (from 0.78 V to 0.84 V) in the related PSCs using Y6 as the electron acceptor. This side-chain engineering strategy could promote the polymer chain interactions and fine-tune the phase separation of active blends, leading to enhanced absorption, ordered molecular packing and crystallinity. Among them, the chlorinated PBDTCl exhibited not only high level absorption and crystallinity, but also the most balanced hole/electron charge transport and the most optimized morphology, giving rise to the best PCE of 13.46 % with a Voc of 0.84 V, a Jsc of 23.16 mA cm−2 and an FF of 69.2 %. The chlorination strategy afforded PBDTCl synthetic simplicity but high efficiency, showing its promising photovoltaic applications for realizing low-cost practical PSCs in near future.

Original languageEnglish
Pages (from-to)11241-11249
Number of pages9
JournalChemistry - A European Journal
Volume26
Issue number49
DOIs
Publication statusPublished - 2020 Sep 1

Keywords

  • energy conversion
  • photovoltaics
  • polymer solar cells
  • sole donor unit
  • synthetic simplicity

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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