Precise Control of Thermal and Redox Properties of Organic Hole-Transport Materials

Valerie A. Chiykowski, Yang Cao, Hairen Tan, Daniel P. Tabor, Edward H. Sargent*, Alán Aspuru-Guzik, Curtis P. Berlinguette

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

We report design principles of the thermal and redox properties of synthetically accessible spiro-based hole transport materials (HTMs) and show the relevance of these findings to high-performance perovskite solar cells (PSCs). The chemical modification of an asymmetric spiro[fluorene-9,9′-xanthene] core is amenable to selective placement of redox active triphenylamine (TPA) units. We therefore leveraged computational techniques to investigate five HTMs bearing TPA groups judiciously positioned about this asymmetric spiro core. It was determined that TPA groups positioned about the conjugated fluorene moiety increase the free energy change for hole-extraction from the perovskite layer, while TPAs about the xanthene unit govern the Tg values. The synergistic effects of these characteristics resulted in an HTM characterized by both a low reduction potential (≈0.7 V vs. NHE) and a high Tg value (>125 °C) to yield a device power conversion efficiency (PCE) of 20.8 % in a PSC.

Original languageEnglish (US)
Pages (from-to)15529-15533
Number of pages5
JournalAngewandte Chemie - International Edition
Volume57
Issue number47
DOIs
StatePublished - Nov 19 2018

Keywords

  • glass transition temperature
  • hole-transport materials
  • organic semiconductors
  • perovskite solar cells
  • solar energy

ASJC Scopus subject areas

  • General Chemistry
  • Catalysis

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