Efficient Inverted Perovskite Solar Cells Enabled by Dopant-Free Hole-Transporting Materials Based on Dibenzofulvene-Bridged Indacenodithiophene Core Attaching Varying Alkyl Chains

Enwei Zhu, Jiantao Wang, Jing Xu, Liying Fu, Ruxue Li, Chengzhuo Yu, Shijie Ge, Xiaosong Lin, Rui Chen, Hongkai Wu, Hsing Lin Wang, Guangbo Che

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Inspired by the structural advantages of spiro-OMeTAD, which is the most commonly used hole-transporting material (HTM), two rationally designed HTMs with butterfly-shaped triarylamine groups based on dibenzofulvene-bridged indacenodithiophene (IDT) core (attaching hexyl and octyl chains) have been synthesized, namely, IT-C6 and IT-C8, respectively. Shorter alkyl-chain-based IT-C6 exhibits a marked increase in glass-transition temperature (Tg) of 105 °C, whereas IT-C8 shows a Tg of 95 °C. Moreover, it is demonstrated that IT-C6 exhibits a higher hole-transporting mobility, more suitable band energy alignment, better interfacial contact, and passivation effect. The inverted devices of employed HTM based on IT-C6 obtained a champion PCE of 18.34% with a remarkable fill factor (FF) of 82.32%, whereas the IT-C8-based device delivered an inferior PCE of 16.94% with an FF up to 81.20%. Both HTMs embodied inverted devices present high FF values greater than 81%, which are among the highest reported values of small molecular HTM-based PSCs. This work reveals that cutting off the symmetrical spiro-core and subsequently combining IDT (attaching tailored alkyl chains) with the spiro-linkage fluorine to construct the orthogonal molecular conformation is a significant principle for the design of promising dopant-free HTMs.
Original languageEnglish (US)
Pages (from-to)13254-13263
Number of pages10
JournalACS Applied Materials and Interfaces
Volume13
Issue number11
DOIs
StatePublished - Mar 24 2021
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science

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