Synthesis and ultrafast spectroscopic study of new [6,6]methanofullerenes

Ultrafast transient absorption and terahertz spectroscopic studies have been performed on new [6,6]methanofullerenes synthesized by the reaction of diazomethane (generated in situ from their hydrazone precursor) with fullerene[60] via our eco-friendly methodology, i.e., amine-assisted 1,3 dipolar cycloaddition (AACA). Synthesized materials have been characterized by different spectroscopic techniques for their structure establishment, including terahertz spectroscopy to study changes in spectra on functionalization. Attachment of different types of functional groups on exohedral chains resulted in band gap tuning. Photoinduced charge generation and charge separation studies have been performed to understand the charge carrier dynamics in a methanofullerene : P3HT mixture. Efficient charge separation efficiency is observed in both the acceptors on mixing with P3HT, making them potential acceptor materials in organic solar cells. High photoconductivity calculated by terahertz time domain spectroscopy of these new fullerene derivatives can also be exploited in other organic electronic devices.