Kaiyuan Deng,Yahong Jin,Lifang Yuan,Haoyi Wu,Yihua Hu
Phosphor-converted light-emitting diode (pc-LED) technology, as artificial lighting source, is the most promising option for providing power for plant growth in future smart agricultural factories. However, developing red phosphors with the desired emission spectral range and good thermal stability is still experimental. In this study, an Mn 4+ -doped BaZrGe 3 O 9 red-emitting phosphor with remarkable thermal stability is reported. The red emission, spanning the wavelength range of 600–800 nm, matches the absorption range of chlorophyll a, b and phytochrome (P r ). Its good thermal stability at 150 °C is in addition to its emission intensity, which is 81.7 % of its room-temperature intensity. Co-doping with Ca 2+ contributes to a 1.7-fold increase in the red emission intensity at room temperature. The encapsulation of the present phosphor onto UV LED chips produces red emitting LED devices, which can be used for garlic and corn cultivation. The implementation reveals that the six-hour artificial red light illumination supplement is the most effective and significant means to promote garlic and corn growth. The as-obtained red-emitting phosphor may be a promising candidate for pc-LEDs promotion of crop growth in agricultural factories.
Cheng Zhang,Congying Shao,Junsheng Wang,Ziwei Li,Mengna Liang,Yongxiang Wang,Dan Liu,Shun Lu
Copper nanoclusters (CuNCs) with bright blue-emitting fluorescence have been synthesized via a simple one-pot process using 2-mercapto-1-methylimidazole (MMI) as a stabilizer. The as-prepared MMI-CuNCs exhibited a high quantum yield of 19.2%, a long luminescence lifetime of 10.57 μs, and excellent photostability. Significantly, the fluorescence intensities of MMI-CuNCs were effectively quenched with addition of Ag+ ions, and the MMI-stabilized CuNCs were developed as a sensitive fluorescent nanoprobe for the label-free determination of silver ions for the first time. The fluorescence sensor provided a fast linear response toward Ag+ in the range of 0.025–50 μM, with a detection limit of 6.7 nM. The fluorescence quenching mechanism was ascribed to an agglomeration-induced effect and static quenching. A fluorescence sensing platform was successfully applied for Ag+ detection in human serum samples with good accuracy and high reproducibility, signifying the practical applicability of the assay. Additionally, MMI-CuNCs displayed good solid-state blue emission and are suitable for security ink applications. The MMI-CuNCs were utilized as a color conversion layer to construct blue- and white-light-emitting diodes (LEDs) with excellent white light properties by a facile combination of MMI-CuNCs and UV LED chips. This result facilitates multiple functions of MMI-CuNCs in the application of label-free sensors, anticounterfeiting, and optical devices.
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