Regioregular Phthalocyanines Substituted with Bulky Donors at Non-Peripheral Positions

Satoshi Yamamoto; Kengo Kuribayashi; Takuro N Murakami; Eunsang Kwon; Martin J Stillman; Nagao Kobayashi; Hiroshi Segawa; Mutsumi Kimura

doi:10.1002/chem.201703105

Regioregular Phthalocyanines Substituted with Bulky Donors at Non-Peripheral Positions

Chemistry. 2017 Nov 2;23(61):15446-15454. doi: 10.1002/chem.201703105. Epub 2017 Oct 13.

Authors

Satoshi Yamamoto¹, Kengo Kuribayashi¹, Takuro N Murakami², Eunsang Kwon³, Martin J Stillman⁴, Nagao Kobayashi¹, Hiroshi Segawa^{5

6}, Mutsumi Kimura¹

Affiliations

¹ Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, 386-8567, Japan.
² Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1- Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
³ Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, 6-3 Aramakiazaaoba, Aoba-ku, Sendai, 990-8578, Japan.
⁴ Department of Biology and Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
⁵ Graduate School of Arts and Science, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
⁶ Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1, Komaba, Megurro-ku, Tokyo, Japan.

PMID: 28884850
DOI: 10.1002/chem.201703105

Abstract

Three regioregular phthalocyanines (1-3) were synthesized selectively by the cyclic tetramerization of phthalonitriles bearing a bulky diarylamine substituent at the next position of nitrile. The steric repulsion at the tetramerization of bulky phthalonitriles allowed for the selective formation of regioregular phthalocyanines as confirmed by NMR and single crystal X-ray structural analyses. The absorption spectrum of 1 substituted with di(4-tert-butylphenyl)amine groups at the non-peripheral positions showed a non-split Q-band at 764 nm, which was redshifted by 83 nm compared with that of metal free phthalocyanine (H₂ Pc). The TD-DFT calculation and electrochemical studies prove that the substitution of diarylamine groups at the α-positions effectively destabilizes the HOMO energy level, which causes a large redshift of the Q-band. Moreover, 1 can generate a one-electron oxidation species through chemical oxidation. The Q-band position of 2 bearing 4,4'-dimetoxyphenylamine units was further shifted by 10 nm compared with that of 1. In addition, 3 having carbazole units showed a small redshift of the Q-band relative to H₂ Pc. The hole-mobility of 2 in thin film was determined to be 1.1×10^-5 cm V^-1 s^-1 by using a space charge limited current method. A perovskite solar cell employing 2 as a hole-transporting layer gave an efficiency of 5.1 % under standard global 100 Wcm^-2 AM 1.5 G illumination.

Keywords: density functional calculations; dyes/pigments; magnetic circular dichroism spectroscopy; perovskite solar cells; phthalocyanines.