New efficient (thio)acetalized fullerene monoadducts for organic solar cells: characterization based on solubility, mobility balance, and dark currentElectronic supplementary information (ESI) available: Experimental details, Fig. S1-S13, Tables S1-S4. CCDC 1025705. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ta05965d

• Main Authors: Mikie, Tsubasa, Saeki, Akinori, Masuda, Hiroyuki, Ikuma, Naohiko, Kokubo, Ken, Seki, Shu
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c4ta05965d

We report a systematic study of organic photovoltaic cells using novel spiro-acetalized and (thio)acetalized [60]fullerene monoadducts bearing five- to seven-membered rings. One of these compounds had power-conversion efficiencies of 5.8% with PTB7 and 4.0% with poly(3-hexylthiophene); the latter is comparable to that of the commonly used [6,6]-phenyl-C 61 -butyric acid methyl ester. We investigated the precise factor that governs the device performance by examining the solubility, space-charge-limited current mobility balance of holes and electrons, morphology, and dark current. Single-crystal X-ray diffraction highlighted the key role of compact and flexible spiro ring folding in the rim space in fullerene packing. We report a systematic study of organic photovoltaic cells using novel spiro-acetalized and (thio)acetalized [60]fullerene monoadducts bearing five- to seven-membered rings.