Additive-Driven Assembly of Block Copolymer-Nanoparticle Hybrid Materials for Solution Processable Floating Gate Memory

The preparation of well-ordered hybrid materials at nanoscale is not only fundamentally interesting but also of significant importance for the development of next generation functional devices. In this study, we present a simple approach for the preparation of well-ordered polymer/NP composites through the concept of additive-driven assembly, and its application for the fabrication of floating gate organic FET memory devices. The addition of gold NPs that selectively hydrogen bond with pyridine in poly(styrene-$b$-2-vinyl pyridine) is shown to induce an ordered structure. This enables the fabrication of well-ordered hybrid materials with lamellar domains at Au NP loadings of more than 40 wt{\%}. The fabrication of floating gate memory devices was demonstrated by the ordered Au NPs / block copolymer hybrid film as a charge trapping layer, which is sandwiched between a SiO$_{2}$ dielectric layer and a poly(3-hexylthiophene) semiconductor layer. This approach enables us to fabricate well-ordered charge storage layers by solution processing and to achieve facile control of the memory windows by changing the density of gold NPs. The devices show high carrier mobility ($>$ 0.1 cm$^{2}$/Vs), controllable memory windows (0$\sim $50V), high \textit{on/off} ratio ($>$10$^{5})$ between memory states and long retention times ($>$10$^{4}$ s). This approach is potentially suitable for roll-to-roll printing techniques to make flexible, large area and high density devices.