Nonvolatile room-temperature luminescent molecular liquids are a new generation of organic soft materials. They possess high stability, versatile optical properties, solvent-free fluid behaviour and can effectively accommodate dopant dye molecules. Here we introduce an approach to optimize anthracene-based liquid materials, focussing on enhanced stability, fluorescence quantum yield, colour tunability and processability, with a view to flexible electronic applications. Enveloping the anthracene core in low-viscosity branched aliphatic chains results in stable, nonvolatile, emissive liquid materials. Up to 96% efficient energy-transfer-assisted tunable emission is achieved by doping a minute amount of acceptor dye in the solvent-free state. Furthermore, we use a thermoresponsive dopant to impart thermally controllable luminescence colours. The introduced strategy leading to diverse luminescence colours at a single blue-light excitation can be an innovative replacement for currently used luminescent materials, providing useful continuous emissive layers in developing foldable devices.
A novel non‐volatile organic memory device is developed based on an organic field effect transistor (OFET) with a dielectric layer of a four‐armed, star‐shaped polymer featuring a copper phthalocyanine (CuPc) core. The CuPc core unit of the star‐shaped polystyrene (CuPc‐PS4) self‐assembles to form aggregates via π–π interactions, which are isolated and dispersed in the polymer thin film. The OFET memory device employing CuPc‐PS4 shows significant hole‐trapping characteristics with a high memory ON/OFF current ratio of 107, long retention ability of over 104 s, and good endurance of more than 100 cycles, which is attributed to a flash‐type memory. The novel polymer design with CuPc core assemblies inside the polymer matrix is a promising candidate for nano floating gates in non‐volatile OFET memory.
20 June 2008 in Angewandte Chemie International Edition