New Core-Expanded Naphthalene Diimides for n-Channel Organic Thin Film Transistors

Four classes of core-expanded naphthalene diimides (1a, 1b, 2a, 2b, 3 and 4) that bear different electron-deficient sulfur heterocycles were designed and synthesized. The solution-processed thin films of 1a, 2a, 3 and 4 operated well in air as n-channel organic transistors with electron mobility ranging from approximate to 10(-6) to 0.14 cm(2)/Vs, depending on the different conjugated backbones. The thin film microstructure studies were also carried out to understand the variations of the electron mobility for thin films of 1a, 2a, 3 and 4.