No abstract

Fluorescent organic nanoparticles based on small molecules have been regarded as promising candidates for bioimaging in recent years. In this study, we report a highly stable near-infrared (NIR) fluorescent organic nanoprobes based on nanoparticles of an anthraquinone derivate with strong aggregation-induced emission (AIE) characteristics and a large Stokes shift (>175 nm). These endow the nanoprobe with high fluorescent brightness and high signal-to-noise ratio. On the other hand, the nanoprobe also shows low cytotoxicity, good stability over a wide pH range, superior resistance against photodegradation and photobleaching comparing to typical commercial fluorescent organic dyes such as fluorescein sodium. Endowed with such merits in term of optical performance, biocompatibility, and stability, the nanoprobe is demonstrated to be an ideal fluorescent probe for noninvasive long-term cellular tracing and imaging applications. As an example, it is shown that strong red fluorescence from the nanoprobe can still be clearly observed in A549 human lung cancer cells after incubation for six generations over 15 days.

Organic light‐emitting diodes (OLEDs) are the most successful product of organic electronics in the market and continually receive attention from scientific and industrial communities. Imidazoles have been extensively investigated for OLED applications, and demonstrated their versatility in molecular design for different functions. This review presents a summary of recent studies on imidazole (including imidazole derived moieties) derivatives, with special focus on discussing various molecular design tactics, for applications as electron‐transporting materials, emitters, and host materials in OLEDs. At last, perspectives and challenges regarding to imidazole semiconductors for electroluminescence applications are also discussed.

Achieving high-performance electroluminescence with EQE of 7.20% and CIEy ∼ 0.06 based on bipolar materials with intercrossed excited state characteristics.

A recent breakthrough in the discovery of thermally activated delayed fluorescence (TADF) emitters characterized by small single-triplet energy offsets (ΔE ST) offers a wealth of new opportunities to exploit high-performance metal-free photosensitizers. In this report, two intrinsically cancer-mitochondria-targeted TADF emitters-based nanoparticles (TADF NPs) have been developed for two-photon-activated photodynamic therapy (PDT) and fluorescence imaging. The as-prepared TADF NPs integrate the merits of (1) high 1O2 quantum yield of 52%, (2) sufficient near-infrared light penetration depth due to two-photon activation, and (3) excellent structure-inherent mitochondria-targeting capabilities without extra chemical or physical modifications, inducing remarkable endogenous mitochondria-specific reactive oxygen species production and excellent cancer-cell-killing ability at an ultralow light irradiance. We believe that the development of such intrinsically multifunctional TADF NPs stemming from a single molecule will provide new insights into exploration of novel PDT agents with strong photosensitizing ability for various biomedical applications.