In this paper, we report a novel organic fluorescent nanoparticle based on exciplexes for cell imaging. Through a reprecipitation method, we used a combination of 1,1-bis((di-4-tolylamino)phenyl) cyclohexane (TAPC) and 2,7-bis(diphenylphosphoryl)-9,9 0 -spirobi[fluorene] (SPPO13) to form nanoparticles. In the aggregated structures, TAPC and SPPO13 were forced into proximity that led to the corresponding exciplex formation. A red-shifted fluorescence emission with considerably longer fluorescence lifetimes ascribed to exciplex emission can be achieved. Along with the good stability and low cytotoxicity of organic nanoparticles, the prepared TAPC/SPPO13 exciplex nanoparticles were successfully applied in live cell imaging. These properties make TAPC/SPPO13 exciplex nanoparticles good candidates for cellular labeling and imaging materials.

5Fluorescent molecule 9,9-bis(4-bromobutyl)-2,7-bis(4-(1,2,2-triphenylvinyl)phenyl)-9H-fluorene, TPEF, comprising a fluorene unit and two tetraphenylethene moieties, has been utilized to serve as a sky-blue emitter in a solution-processed non-doped organic light-emitting diode (OLED), and its optical and electrical properties are investigated. The TPEF is an aggregation-induced emission (AIE)-active molecule. It is nearly non-emissive when dissolved in solution while emits strong fluorescence in solid 10 state, indicating that it could be a promising candidate for electrofluorescence use. The solution-processed TPEF-based OLED with a simple non-doped structure exhibits sky-blue fluorescence emission, showing a maximum luminance of 2618 cd m −2 , a maximum current efficiency of 4.55 cd A −1 , and a maximum external quantum efficiency (EQE) of 2.17%.A sky-blue fluorescent small molecule was employed to fabricate the non-doped emissive layer of solution-processed OLED.

No abstract

Metal-enhanced fluorescence was realized in the emissive layer of organic electroluminescent devices. Core-shell Au nanoparticles (Au@SiO2) doped into the emissive layer of polymer light-emitting diodes (PLEDs) were used to enhance the luminous efficiency by a factor of 1.6 relative to the undoped reference devices (from 6.3 cd/A to 10.0 cd/A). The silica shell outside the Au nanoparticles was used to ensure that there was sufficient distance between the Au nanoparticles and the fluorescent polymer material to avoid quenching of the excitons. In addition, sufficient overlap of the energy of the localized surface plasmon resonance of the Au nanoparticles and the energy of the excitons formed in the emissive layer was guaranteed. These led to an enhanced PLED efficiency. This research provides a way to obtain high performance organic electroluminescent devices.