Carbon Black: A Precursor for Fullerene and Metallofullerene Production

Thermal black, a form of carbon black, has been found to readily produce fullerene and metallofullerene positive ions in laser ablation Fourier transform ion cyclotron resonance mass spectrometry experiments. The metallofullerene ions observed include LaC n + ( n = 44−96), CaC n + ( n = 50−∼120), and Ca 2 C n + ( n = 70−∼90). These ions were produced from the laser ablation of lanthanum oxide/thermal black or calcium carbonate/thermal black mixtures. Investigations using 1064 nm wavelength radiation with two laser pulse lengths at 8 ns and 230 μs and at various laser powers indicate that the longer pulse length radiation is advantageous to metallofullerene production. For fullerene ion production a laser power density window of <500 MW cm -2 but >15 000 MW cm -2 for the 8 ns, 1064 nm radiation was observed whereas with the 230 μs, 1064 nm radiation the fullerene ions were produced with laser powers of only 100−1500 kW cm -2 .