Naphthalene diimide (NDI) copolymers are attractive n-type materials for use in organic electronic devices. Four highly soluble NDI polymers are presentedeach differing only in the thiophene content comprising the material. Electron mobilities as high as 0.076 cm2 V−1 s−1 for the novel material PNDI-3Th are reported. Polymer crystallinity and general macromolecular order are shown to effectively improve by increasing the number of thiophene units within the polymer backbone. The structure−property relationship of NDI−thiophene copolymers is presented and discussed as it pertains to organic field effect transistor (OFET) performance.

Solution-processable n-type ladder-based polymers are highly desirable due to their potential capability to form strong π–π interactions. A series of 5 highly soluble naphthalene diimide (NDI) polymers are presented, differing in the degree to which they are able to form imine-bridged ladder polymer structures. Average electron mobilities as high as 0.0026 cm2 V–1 s–1, which show an electron-mobility improvement of 4 orders of magnitude following ladderization, and on/off current ratios on the order of 104 are reported for the novel material PNDI-2BocL, an alkyl-substituted poly(benzoquinolinophenanthrolinedione). The structure–property relationship of the aforementioned series of copolymers is presented and discussed as it pertains to organic field-effect transistor (OFET) performance.

In this study, we demonstrate in‐situ n‐doping and crosslinking of semiconducting polymers as efficient electron‐transporting materials for inverted configuration polymer solar cells. The semiconducting polymers were crosslinked with bis(perfluorophenyl) azide (bis‐PFPA) to form a robust solvent‐resistant film, thereby preventing solvent‐induced erosion during subsequent solution‐based device processing. In addition, chemical n‐doping of semiconducting polymers with (4‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzoimidazol‐2‐yl)phenyl)dimethylamine (N‐DMBI) substantially improved the power conversion efficiency of solar cells from 0.69% to 3.42%. These results open the way for progress on generally applicable polymeric interface materials, providing not only high device performance but also an effective fabrication method for solution‐processed multilayer solar cell devices.

Naphthalene diimide copolymers are attractive ntype materials due to their high electron affinities, high electron mobilities, and exceptional stability. Herein, we report a series of NDI-fused-thiophene based copolymers with each copolymer differing in the number of fused thiophenes in the donor monomer. Increasing the number of fused-thiophene moieties within an NDI-copolymer backbone is shown to not only enable tuning of the electronic structure but also improve charge mobilities within the active layer of organic field-effect transistors. Electron mobilities and on/off ratios as high as 0.012 cm 2 V 21 s -1 and I on / I off > 10 5 were measured from n-channel thin-film transistors fabricated using NDI-xfTh copolymers. Bulk heterojunction solar cell devices were also fabricated from the NDI-xfTh copolymer series in blends with poly(3-hexylthiophene) (P3HT) with PNDI-4fTh-based devices yielding the largest J sc (0.57 mA cm 22 ) and fill factor (55%) in addition to the highest measured PCE for this series (0.13%).

Silicone elastomers have broad versatility within a variety of potential advanced materials applications, such as soft robotics, biomedical devices, and metamaterials. A series of custom 3D printable silicone inks with tunable stiffness is developed, formulated, and characterized. The silicone inks exhibit excellent rheological behavior for 3D printing, as observed from the printing of porous structures with controlled architectures. Herein, the capability to tune the stiffness of printable silicone materials via careful control over the chemistry, network formation, and crosslink density of the ink formulations in order to overcome the challenging interplay between ink development, post-processing, material properties, and performance is demonstrated.