the breakthrough towards practical applications came in 1990 when wolfgang kratschmer of the max plank institute for nuclear physics in heidelberg and don huffman of the university of arizona in tucson discovered a simple way of making relatively large amounts of c. they vaporised graphite electrodes in a low-pressure helium atmosphere , producing a sooty black mist from which pure fullerene could be extracted as a reddish solution and then crystallised as a slippery yellow solid .