By monomer‐mediated in‐situ growth synthesis strategy, with hydroquinone and 1,3,5‐tris(4‐aminophenyl)benzene as monomers, a core‐shell magnetic porous organic polymer was synthesized through a simple azo reaction. Based on this, a magnetic solid‐phase extraction–high‐performance liquid chromatography–fluorescence detection method was proposed for the analysis of fluoroquinolones in a honey sample. With ofloxacin, ciprofloxacin, enrofloxacin, lomefloxacin, and difloxacin as target analytes, factors affecting the extraction efficiency had been optimized. The LODs were 1.5–5.4 ng/L (corresponding to 0.23–0.81 μg/kg in honey). The linear range was 0.005–20 μg/L for difloxacin, 0.01–20 μg/L for ofloxacin, ciprofloxacin and lomefloxacin, and 0.02–20 μg/L for enrofloxacin. The enrichment factor was 84.4–91.7‐fold with a high extraction efficiency of 84.4–91.7%. The method was assessed by the analysis of target fluoroquinolones in honey samples, and the recoveries for the spiked samples were 79.3–95.8%. The results indicated that the established magnetic solid‐phase extraction–high‐performance liquid chromatography–fluorescence detection method is efficient for the analysis of trace fluoroquinolones in honey.

InP quantum dots (QDs) attract growing interest in recent years, owing to their environmental advantages upon applications in display and lighting. However, compared to Cd-based QDs and Pb-based perovskites, the synthesis of InP QDs with high optical quality is relatively more difficult. Here, we established a mid-synthetic modification approach to improve the optical properties of InP-based QDs. Tris(dimethylamino)phosphine ((DMA)3P) and indium iodide were used to prepare InP QDs with a green emission (∼527 nm). By introducing zinc halides (ZnX2) during the mid-synthetic process, the photoluminescence quantum yield (PLQY) of the resulting InP/ZnSeS/ZnS core/shell/shell QDs was increased to >70%, and the full-width-at-half-maximum (FWHM) could be narrowed to ∼40 nm. Transmission electron microscopy clearly showed the improvement of the QDs particle size distribution after introducing ZnX2. It was speculated that ZnX2 was bound to the surface of QDs as a Z-type ligand, which not only passivated surface defects and suppressed the emission of defect states but also prevented Ostwald ripening. The InP cores were also activated by ZnX2, which made the growth of the ZnSeS shell more favorable. The photoluminescence properties started to be improved significantly only when the amount of ZnX2 exceeded 0.5 mmol. As the amount increased, more ZnX2 was distributed around the QDs to form a ligand layer, which prevented the shell precursor from crossing the ligand layer to the surface of the InP core, thus reducing the size of the InP/ZnSeS/ZnS QDs. This work revealed a new role of ZnX2 and found a method for InP QDs with high brightness and low FWHM by the mid-synthetic modification, which would inspire the synthesis of even better InP QDs.

Inorganic metal halide perovskites have very promising applications in light-emitting diodes (LED), solar cells, lasers, and photodetectors owing to their outstanding optoelectronic characteristics. However, halide segregation is quite a challenge in the industrialization process of pure red perovskite LEDs with stable emission. In this work, we addressed this issue by doping with KBr in the nucleation of nanocrystals (NCs) and postmodifying with quaternary ammoniums (e.g., tetrabutylammonium bromide, TBAB). Mixed halide perovskite NCs (CsPbI 3−x Br x NCs) with excellent optical performances and stabilities were obtained. The emission maximum was at ∼636 nm, and the full-width-at-half-maximum (fwhm) was 28 nm, achieving the requirement of Rec. 2020. The solution and film of KBr/TBAB-CsPbI 3−x Br x NCs could keep pure red emission after exposure in the air for 65 and 90 days, respectively. The photoluminescence quantum yield (PLQY) of the KBr/TBAB-CsPbI 3−x Br x NCs solution remained 90% and the emission peak had only a very slight shift after 240 h of irradiation at 365 nm. This study demonstrated an efficient route for highly stable pure red perovskite NCs and highlighted the critical role of surface ligands, which is expected to be applied in the future.

Prepared magnetic porous organic polymers show high extraction efficiency towards cardiovascular drugs.