Active sites-enriched carbon matrix enables efficient triiodide reduction in dye-sensitized solar cells: An understanding of the active centers

Xiangtong Meng, Chang Yu, Xuepeng Zhang, Longlong Huang, Matthew Rager, Jiafu Hong, Jieshan Qiu, Zhiqun Lin

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Understanding the activity origins of electrocatalysts for the triiodide (I3 -) reduction is highly desirable in dye-sensitized solar cells (DSSCs). Herein, we report a robust strategy to craft nitrogen-doped carbon nanowires (NCWs) through combining oxidation polymerization from p-phenylenediamine with carbonization process. Owing to the abundant edges of the graphite microcrystals embedded in the NCWs and the incorporated N species, the NCWs synthesized at 700 °C exhibit a superior response to the I3 - reduction in DSSCs with a high power conversion efficiency of 8.90%, outperforming the Pt reference (8.09%), and a high stability is also manifested. Theoretical calculations reveal that, of various doped N species within NCWs, the quaternary N species can significantly decrease the ionization energy and modulate the spin density distribution of carbon frameworks, thus promoting the electron transfer from the external circuit to the electrolyte. Natural population analysis further reveals that the active centers within the NCWs for the I3 - reduction are those positively charged carbon atoms adjacent to the quaternary N. As such, this work will pave an avenue for rational design and engineering of inexpensive yet high-efficiency carbon electrocatalysts for the advanced energy applications.

Original languageEnglish
Pages (from-to)138-147
Number of pages10
JournalNano Energy
Volume54
DOIs
StatePublished - Dec 2018

Bibliographical note

Funding Information:
This work was partly supported by the National Natural Science Foundation of China ( NSFC ) of China (Nos. 21522601 , U1508201 ), the Fundamental Research Funds for the Central Universities of China ( DUT16ZD217 ), and the National Key Research Development Program of China ( 2016YFB0101201 ). X. Meng also thanks the financial support from China Scholarship Council ( 201606060061 ).

Publisher Copyright:
© 2018

Keywords

  • Active site
  • Counter electrode
  • Dye-sensitized solar cell
  • Electrocatalytic activity
  • Nitrogen-doped carbon nanowire

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