Design and fabrication of remote‐controllable micromachines by femtosecond laser‐induced two‐photon polymerization (TPP) of novel ferrofluids resin composed of methacrylate groups modified Fe3O4 nanoparticles and photoresists is demonstrated. As two typical models, a micro‐spring and a micro‐turbine were successfully fabricated for precise motion control. The development of remotely controllable micro‐nanomachines would shorten the distance between actionless micro‐nanostructures and smart microrobots.

A family of donor–acceptor–donor (D–A–D) type near-infrared (NIR) fluorophores containing rigid nonplanar conjugated tetraphenylethene (TPE) moieties was designed and synthesized through Stille coupling reactions with electron-deficient [1,2,5]thiadiazolo[3,4-g]quinoxaline (QTD) or benzo[1,2-c;4,5-c′]bis[1,2,5]thiadiazole (BBTD) as acceptors. The absorption, fluorescence, and electrochemical properties were studied. These compounds exhibited good aggregation-induced emission enhancement (AIEE) property, as a result of the twisted TPE units, which restrict the intramolecular rotation and reduce the π–π stacking. Photoluminescence of these chromophores ranges from 600 to 1100 nm, and their HOMO–LUMO gaps are between 1.85 and 1.50 eV. Non-doped organic light-emitting diodes (OLEDs) based on these fluorophores were made and exhibited EL emission spectra peaking from 706 to 864 nm. The external quantum efficiency (EQE) of these devices ranged from 0.89% to 0.20% and remained fairly constant over a range of current density of 100–300 mA cm–2. The device with the highest solid fluorescence efficiency emitter 1a shows the best performance with a maximum radiance of 2917 mW Sr–1 m–2 and EQE of 0.89%. A contrast between nondoped and doped OLEDs with these materials confirms that AIEE compounds are suitable for fabricate efficient nondoped NIR OLEDs.

Exciton quenching dynamics has been systematically studied in pristine P3HT and nano phase separated P3HT/PCBM blend films under various excitation intensities by femtosecond fluorescence up-conversion technique. The behaviors of excitons in the films can be well described by a three-dimensional diffusion model. The small diffusion length and large charge transfer radius indicate that excitons reach the interface most likely by the delocalization of the excitons in P3HT fibrillar at a range of 4.8-9 nm so that the excitons can quickly delocalize in the P3HT domain to reach the interface (instead of by diffusion).