Organic bistable memory switching phenomena and H-like aggregates in squarylium dye Langmuir-Blodgett films

We have investigated the relationship between the organic bistable memory switching phenomena and H-like aggregates in squarylium dye Langmuir-Blodgett (SQ LB) films. The current-voltage characteristics of SQ LB films sandwiched between the top gold electrode and the bottom aluminum electrode were measured in a dark vacuum vessel at various temperatures as a function of the number of SQ LB films. Ultraviolet-visible absorption spectra were measured at various temperatures. The switching voltage increased as the temperature increased between room temperature and 100 °C, and did not depend on the number of SQ LB films. The results revealed that conductance switching phenomena were induced at the interface between the top gold electrode and SQ LB films, and caused by the presence of H-like aggregates in the SQ LB films.