Carbon nanotube versus graphene in modifying the electrical and optical properties of organic nonlinear optical material

4- N , N -dimethylamino-4′- N ′-methyl-stilbazolium tosylate (DAST) is an important organic nonlinear optical material, but its applications in electronic devices are limited by its poor electrical conductivity. To tackle this problem, DAST–carbon nanotube (CNT) and DAST–graphene (G) binary composite films, as well as DAST–CNT–G ternary composite films were prepared and compared. Results indicate that both the electrical and optical properties of DAST can be effectively modified by CNT or G. Moreover, electrical percolation phenomena are observed in the DAST-based binary composite films at ~ 6.7 wt% CNT or ~ 2.0 wt% G. The as-prepared DAST–CNT films show higher electrical conductivity, while the DAST–G films exhibit higher temperature coefficient of resistance. Particularly, comprehensive optimal properties are observed in the DAST–CNT–G composite films, combining both advantages of DAST–CNT and DAST–G binary composite films, revealing the synergistic effects of CNT and G in the resultant ternary composite films.