Four classes of core-expanded naphthalene diimides （la, lb, 2a, 2b, 3 and 4） that bear different elec- tron-deficient sulfur heterocycles were designed and synthesized. The solution-processed thin films of la, 2a, 3 and 4 operated well in air as n-channel organic transistors with electron mobility ranging from MO 6 to 0.14 cm2/Vs, depending on the different conjugated backbones. The thin film microstructure studies were also carried out to un- derstand the variations of the electron mobility for thin films of la, 2a, 3 and 4. 相似文献
Gas sensors based on organic semiconductors receive tremendous attentions owing to their advantages on high selectivity and room temperature operation. However, until now, most organic semiconductor based sensors still suffered from problems, such as low sensitivity, slow response/recovery speed and poor stability. In addition, a clear correlation between the sensing performance and the film property is still absent. Herein, we report the investigation on sensing performance of a series of organic films with various morphologies. By simply adjusting the quality of self-assembled monolayer(SAM) on the silicon wafer surface, we obtain organic semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) films with varied morphologies and different charge transport abilities. The film with a small grain size and a continuous morphology presents the highest sensing performance to NO2, with a sensitivity up to 730%/ppm(ppm=parts per million, vo-lume ratio). We thus reveal that the high sensitivity of the organic film is evident related with the charge transport ability and initial conductivity of the films, as well as the morphologies of both modification layer and the active films. 相似文献
The performance of polymer field‐effect transistors (PFETs) based on short rigid rod semiconducting poly(2,5‐didodecyloxy‐p‐phenyleneethynylene) (D‐OPPE) is highlighted. The controlled heating and cooling of thin films of D‐OPPE allows for a recrystallization from the melt, boosting the performance of D‐OPPE‐based transistors. The improved film properties induced by controlled annealing lead to a hole field‐effect mobility around 0.014 cm2 V−1 s−1, an on/off ratio of 106, a sub‐threshold swing of 3 V dec−1 and a threshold voltage of −35 V, employing a poly(methyl methacrylate) (PMMA) gate dielectric. Thus, PFETs out of D‐OPPE compete now with spin‐coated, polycrystalline poly(3‐hexylthiophene)‐based PFETs.
