title: Enhancing the hole-conductivity of spiro-OMeTAD without oxygen or lithium salts by using spiro(TFSI)₂ in perovskite and dye-sensitized solar cells.
abstract: 2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), the prevalent organic hole transport material used in solid-state dye-sensitized solar cells and perovskite-absorber solar cells, relies on an uncontrolled oxidative process to reach appreciable conductivity. This work presents the use of a dicationic salt of spiro-OMeTAD, named spiro(TFSI)2, as a facile means of controllably increasing the conductivity of spiro-OMeTAD up to 10(-3) S cm(-1) without relying on oxidation in air. Spiro(TFSI)2 enables the first demonstration of solid-state dye-sensitized solar cells fabricated and operated with the complete exclusion of oxygen after deposition of the sensitizer with higher and more reproducible device performance. Perovskite-absorber solar cells fabricated with spiro(TFSI)2 show improved operating stability in an inert atmosphere. Gaining control of the conductivity of the HTM in both dye-sensitized and perovskite-absorber solar cells in an inert atmosphere using spiro(TFSI)2 is an important step toward the commercialization of these technologies.
authors: Department of Chemistry and †Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors: William H
authors: WH
authors: Nguyen
authors: Colin D
authors: CD
authors: Bailie
authors: Eva L
authors: EL
authors: Unger
authors: Michael D
authors: MD
authors: McGehee