Electrical bistability of copper (I) sulfide nanocrystals blending with a semiconducting polymer

Electrically bistable devices were fabricated based on blends of n-dodecanethiol capped copper (I) sulfide (Cu2S) nanocrystals and a semiconducting polymer using a simple spin-coating method. Reproducible electrical bistability and negative differential resistance effects were observed in current-voltage characteristics. A large ON/OFF current ratio of 10(4) at negative voltages could be obtained by applying different amplitude of sweeping voltages and varying the mass ratios of Cu2S nanocrystals to polymer. The observed conductance switching was speculated to be resulted from electric-filed-induced charge transfer between the nanocrystals and polymer, and negative differential resistance behavior could be attributed to the charge trapping in the nanocrystals. (C) 2009 American Institute of Physics. [doi:10.1063/1.3243981]