No abstract

Aggregation-induced emission (AIE) and antenna effect (AE) are two important luminescence behaviors. Connecting them into polymers is a promising but challenging work, which can supply opportunities for luminescence materials with extensive applications. In this work, AIE-active Eu3+-coordinated polymers (Poly-Eu-1, -2, -3, and -4) have been synthesized, and the efficient AE was verified. This finding presents a facile approach to obtain the Ln3+-based solid luminescence materials due to the synergistic effect from AIE and AE. Also, benefiting from the film-processing ability and water solubility, Poly-Eu-1, -2, -3, and -4 could be employed with different application purposes. In the solution phase, they can be used as sensitive optical probes to detect trace amounts of H2O and D2O, and the limit of detection (LOD) of Poly-Eu-2 toward D2O in H2O is determined to be 7.8 ppm. This discovery is a novel strategy for the construction of D2O optical sensors with a totally intervention-free style.

In comparison with fluorescence molecules with aggregation-caused quenching (ACQ), fluorescence molecules with aggregation-induced emission (AIE) have great advantages in cell imaging, image-guided photodynamic therapy (PDT), and antibacterial activity. However, the reasonable design and synthesis of related molecules are still of great challenges. Herein, a consecutive strategy via several reliable reactions to prepare a series of AIE-active luminogens by adjusting their structures is reported. Having concentrated on the factors for the principle purpose of 1 O 2 generation, TPA-18 is picked out within all triphenylamine (TPA) derivatives according to its longer emission wavelength (640 nm in solid), the lowest energy gap between HOMO and LUMO (calculated as 2.04 eV), the totally separated orbital distributions of HOMO and LUMO, and typical AIE characteristics. Meanwhile, owing to the presence of the positive structural charge and the bright emission color, TPA-18 in aggregated form is detected as an impressive probe for the mitochondria-targeted imaging and living zebrafish embryos imaging in vivo. Accordingly, TPA-18 can effectively generate 1 O 2 reactive oxygen species; it provides an effective application for image-guided photodynamic cancer treatment and antibacterial activity. Therefore, this study not only synthesized AIE photosensitizer with tunable emission wavelength (from blue to red color) but also raised a new concept for the constructing AIEgens with versatile applications in cell imaging, antibacterial activity, and image-guided PDT.

Lanthanide­(III)-based luminescent materials have attracted great research interests due to their unique optical, electronic, and chemical characteristics. Up to now, how to extend these materials into large, broad application fields is still a great challenging task. In this contribution, we are intended to present a simple but facile strategy to enhance the luminescence from lanthanide ions and impart lanthanide­(III)-based luminescent materials with more applicable properties, leading to meet the requirements from different purposes, such as being used as highly emissive powders, hydrogels, films, and sensitive probes under external stimuli. Herein, a water soluble, blue color emissive, temperature sensitive, and film-processable copolymer (Poly-ligand) was designed and synthesized. Upon complexing with Eu3+ and Tb3+ ions, the red color-emitting Poly-ligand-Eu and green color-emitting Poly-ligand-Tb were produced. After finely tuning the ratios between them, a standard white color emitting Poly-ligand-Eu1:Tb4 (CIE = 0.33 and 0.33) was obtained. Furthermore, the resulted materials not only possessed the emissive luminescent property but also inherited functions from the copolymer of Poly-ligand. Thus, these lanthanide­(III)-based materials were used for fingerprint imaging, luminescent soft matters formation, colorful organic light-emitting diode device fabrication, and acid/alkali vapors detection.

Desert plants survive harsh environment using a variety of drought-resistant structural modifications and physio-ecological systems. Rolled-leaf plants roll up their leaves during periods of drought, making it difficult to distinguish between the external structures of various types of plants, it is therefore necessary to carry out spectral characteristics analysis for species identification of these rolled-leaf plants. Based on hyper-spectral data measured in the field, we analyzed the spectral characteristics of seven types of typical temperate zone rolled-leaf desert plants in the Hexi Corridor, China using a variety of mathematical transformation methods. The results show that: (1) during the vigorous growth period in July and August, the locations of the red valleys, green peaks, and three-edge parameters, namely, the red edge, the blue edge, and the yellow edge of well-developed rolled-leaf desert plants are essentially consistent with those of the majority of terrestrial vegetation types; (2) the absorption regions of liquid water, i.e., 1400-1500 and 1600-1700 nm, are the optimal bands for distinguishing various types of rolled-leaf desert plants; (3) in the leaf reflectance regions of 700-1250 nm, which is controlled by cellular structure, it is difficult to select the characteristic bands for differentiation rolled-leaf desert vegetation; and (4) after processing the spectral reflectance curves using a first-order differential, the envelope removal method, and the normalized differential ratio, we identify the other characteristic bands and parameters that can be used for identifying various types of temperate zone rolled-leaf desert plants, i.e., the 510-560, 650-700 and 1330-1380 nm regions, and the red edge amplitude. In general, the mathematical transformation methods in the study are effective tools to capture useful spectral information for species identification of rolled-leaf plants in the Hexi Corridor.