Nonvolatile Organic Thin Film Transistor Memory Devices Based on Hybrid Nanocomposites of Semiconducting Polymers: Gold Nanoparticles

We report the facile fabrication and characteristics of organic thin film transistor (OTFT)-based nonvolatile memory devices using the hybrid nanocomposites of semiconducting poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) and ligand-capped Au nanoparticles (NPs), thereby serving as a charge storage medium. Electrical bias sweep/excitation effectively modulates the current response of hybrid memory devices through the charge transfer between F8T2 channel and functionalized Au NPs trapping sites. The electrical performance of the hybrid memory devices can be effectively controlled though the loading concentrations (0-9 %) of Au NPs and organic thiolate ligands on Au NP surfaces with different carbon chain lengths (Au-L6, Au-L10, and Au-L18). The memory window induced by voltage sweep is considerably increased by the high content of Au NPs or short carbon chain on the ligand. The hybrid nano composite of F8T2:9% Au-L6 provides the OTFT memories with a memory window of similar to 41 V operated at +/- 30 V and memory ratio of similar to 1 x 10(3) maintained for 1 x 10(4) s. The experimental results suggest that the hybrid materials of the functionalized Au NPs in F8T2 matrix have the potential applications for low voltage-driven high performance nonvolatile memory devices.