Silver is a common catalyst in industrial production, and the frequent use of Ag+ can cause water pollution. Thus, the detection of Ag+ in the environment is necessary to determine the level of pollution from silver. In this work, we designed a new, highly selective near-infrared (NIR) fluorescent probe QCy to detect Ag+. The probe exhibits “turn-off” fluorescence quenching responses at 760 nm towards Ag+ over other relevant cations, with outstanding sensitivity and a low detection limit (0.03 µM), which is considerably lower than the standard of the World Health Organization (WHO) for drinking water (0.9 µM). Meanwhile, QCy showed a very good linearity at a low concentration of Ag+ with a ‘naked eye’ visible color change of solution from blue to red. The probe has been applied successfully for the detection of Ag+ in real water samples.

A new microfluidic-assisted self-healing-driven assembly strategy enabling continuous and controllable construction of programmed ordered assemblies is developed by Su Chen and co-workers in article number 1803475. This allows self-assembly to be carried out on the macroscopic scale toward tissue materials and light-emitting diode devices.

Methods allowing construction of macroscopic programmed materials in a flexible and efficient fashion are highly desirable. However, the existing approaches are far removed from such materials. A new self-healing-driven assembly (SHDA) strategy to fabricate various programmed materials by using uniform gel beads (microsize of 212 µm or millimeter size of 4 mm) as building blocks is described here. In virtue of hydrogen bonds and host-guest interactions between gel beads, a series of linear, planar, and 3D beaded assemblies are fabricated via SHDA in microfluidic channels in a continuous and controlled manner. From the perspective of practical applications, the use of gel assemblies is exploited for tissue engineering with controlled cells coculture, as well as light conversion materials toward white-light-emitting diodes (WLEDs). The SHDA strategy developed in this study gives a new insight into the facile and rapid fabrication of various programmed materials toward biological tissue and optoelectronic device.

Hybrid organic-inorganic and all-inorganic metal halide perovskite nanocrystals (PNCs) have aroused extensive attention from both academic and industrial researchers, considering their excellent performance in optoelectronic applications. Herein, we develop a facile and time-saving strategy to synthesize NH2CH═NH2PbBr3 (NH2CH═NH+, FA) PNCs at room temperature. Benefiting from this facile method, high-quality FAPbBr3 PNCs with photoluminescence quantum yield up to 76% and narrow full width at half-maxima of 20 nm can be produced on a large scale. Moreover, anion-exchange reactions run by using FAPbBr3 as a template, producing various PNCs with different anion constituents. By manipulating the ratios of two different anions, a series PNCs with various bright photoluminescence ranging from 452 to 646 nm could be done. On account of superior and adjustable photoluminescence over the visible spectral region, FAPbBr3 PNCs can be applied as a promising color-converting material in liquid-crystal display (LCD) backlight, white light-emitting diode (WLED), and inkjet printing pattern. As a proof of concept, FAPbBr3 PNCs with green emission were integrated in WLED and LCD backlight, accomplishing a color rendering index of 87.5 and a wide color gamut of 116%, respectively.

Fluorescent CdTe nanocrystals (NCs) capped with beta-cyclodextrin (β-CD) are successfully synthesized by host-guest supramolecular assembly of the hydrophobic alkyl chains of N-acetyl-l-cysteine (NAC) on the surface of CdTe NCs and eco-friendly β-CD via the promising simple hydrothermal method in our experiments. The as-prepared NCs display better stability and lower toxicity compared with traditional those only capped with NAC. Specially, cytotoxicity experiments to human umbilical vein endothelial cells in vitro and zebrafish embryo toxicological tests in vivo are performed to determine the toxicity of CdTe NCs. For their practical applications, the promising red-luminescent NCs are employed as stable and low poison red phosphors to fabricate white light-emitting diodes (WLEDs) with remarkable color-rendering index (CRI) being 91.6. This research offers significance for solving the difficulty in toxicity and instability of heavy metal based NCs, which has potential applications in future optoelectronic devices and biomarkers.

We demonstrated a green avenue to continuous mass production of stably fluorescent perovskite nanocrystal composite materials via a microfluidic spinning technique, potentially useful for application in WLEDs and displays.

We synthesized luminescent CsPbBr3 nanocrystals with a high quantum yield and realized patterning and color-purity light-emitting diode applications.

Organometal halide perovskites (such as CH3NH3PbX3, X = Cl, Br, I) have received enormous interest due to their strikingly photoelectric properties. Here we develop a facile ligand-assisted reprecipitation method to synthesize NH2CH = NH2PbX3 (NH2CH = NH2+, FA; X = Br and I) perovskite quantum dots (QDs) at room temperature. The FAPbX-3 perovskite QDs with uniform monodispersity (sized 4-7 nm) display relatively high photoluminescence quantum yields (PLQYs) of 60-75%. Through manipulating the mixed-organic-cation reactions, we achieve a series of multicolored perovskite QDs with continuously controllable emission wavelengths from 460 to 565 nm. Furthermore, we discuss the influence of ligands (oleic acid and n-octylamine) on PL properties and stabilities of perovskite QDs. Finally, we have successfully designed a white LED via compositing perovskite QDs and poly(methyl methacrylate) (PMMA), which presents a high color rendering index. Considering those remarkable achievements, we believe our work will have great potential to meet various optoelectronic applications.

Xiafang Du,‡ Guan Wu,‡ Jian Cheng, Hui Dang, Kangzhe Ma, Ya-Wen Zhang, Peng-Feng Tan and Su Chen* Metal halide perovskites, such as CsPbX3 (X 1⁄4 Cl, Br, and I), have gained extensive attention due to their increasing demand in optoelectronic applications such as solar cells and lighting-emitting devices. Herein, we report a versatile approach to synthesize high-quality CsPbBr3 perovskite nanocrystals (sized 5–15 nm) by ligand-assisted reprecipitation at room temperature. The monodispersed CsPbBr3 nanocube perovskites displayed relatively high photoluminescence quantum yields of 50–80%. By virtue of the quantum size effects, the bandgap energies were manipulated from blue to green spectral regions (410–530 nm). In addition, through compositional modulations of the anion exchange technique, the bright photoluminescence could be almost tuned over the entire visible spectral region (450–650 nm). Furthermore, the photoluminescence of the CsPbBr3 nanocrystals was characterized by narrow emission line widths of 15–50 nm and radiative lifetimes of 5–15 ns. Finally, by taking advantage of these outstanding merits, the CsPbBr3 perovskites were successfully utilized in the application of highly fluorescent patterning and color-purity light-emitting diodes.