1. Influence of Alkoxy Chain Length on the Properties of Two‐Dimensionally Expanded Azulene‐Core‐Based Hole‐Transporting Materials for Efficient Perovskite Solar Cells
- Author
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Tomoya Nakamura, Jaehyun Lee, Ai Shimazaki, Atsushi Wakamiya, Takeshi Hasegawa, Michael Grätzel, Mina Jung, Yasujiro Murata, Minh Anh Truong, Shaik M. Zakeeruddin, Masashi Ozaki, Richard Murdey, Nobutaka Shioya, and Ji-Youn Seo
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Energy conversion efficiency ,General Chemistry ,Azulene ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Amorphous solid ,chemistry.chemical_compound ,Crystallography ,Alkoxy group ,Side chain ,Molecule ,Alkyl ,Perovskite (structure) - Abstract
A series of two-dimensionally expanded azulene-core-based π systems have been synthesized with different alkyl chain lengths in the alkoxy moieties connected to the partially oxygen-bridged triarylamine skeletons. The thermal, photophysical, and electronic properties of each compound were evaluated to determine the influence of the alkyl chain length on their effectiveness as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). All the synthesized molecules showed promising material properties, including high solubility, the formation of flat and amorphous films, and optimal alignment of energy levels with perovskites. In particular, the derivatives with methyl and n-butyl in the side chains retained amorphous stability up to 233 and 159 °C, respectively. Such short alkoxy chains also resulted in improved electrical device properties. The PSC device fabricated with the HTM with n-butyl side chains showed the best performance with a power conversion efficiency of 18.9 %, which compares favorably with that of spiro-OMeTAD-based PSCs (spiro-OMeTAD=2,2',7,7'-tetrakis[N,N-bis(p-methoxyphenyl)amino]-9,9'-spirobifluorene).
- Published
- 2019