Improved thermal stability of nonpolymeric organic glasses by doping with fullerene C-60

The doping of nonpolymeric organic glasses with C-60 is found to improve th eir thermal stability. Films of triphenylamine dimer (TPD) N,N-'-diphenyl-N ,N-'-(3-methyl-phenyl)-1,1(')-biphenyl-4,4(')-diamine, doped with fullerene C-60 and 7,7,8,8-tetracyano-quinodimethane (TCNQ) on a level between 10 an d 20 mol %, were prepared using vacuum codeposition techniques. While undop ed and TCNQ-doped TPD films tend to crystallize under ambient conditions, n o crystallization occurs on C-60-doped TPD films on minimum doping level of 15 mol %. The crystallization can be suppressed even at temperatures about 333 K, the glass transition temperature of pure TPD, if the doping level o f the C-60-doped TPD films reaches 20 mol %. (c) 1999 American Institute of Physics. [S0003-6951(99)03224-6].