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In this study, a novel flexible and robust dual-network supramolecular elastic film with solvent resistance and brilliant structural colors was prepared by combining a Zn2+-crosslinked supramolecular elastic film with polystyrene@silica (PS@SiO2) colloidal crystals. This structurally colored supramolecular elastic material consisted of a covalent support network formed by three different monomers and a Zn2+-crosslinked polyacrylic acid (PAA) coordination network, which provided high mechanical strength and flexibility. The tensile and compression stress of this structural color reached 3.26 MPa at a strain of 187% and a pressure of 300 N. The reflectance wavelength of the structural color film remained unchanged after loading–unloading cycles and compression cycles. The structural color film could be bent and unfolded without heating or the application of an external stimulus. Moreover, the structural color film exhibited resistance to solvents in saturated organic vapors and remained color invariant. [ABSTRACT FROM AUTHOR]

Utilizing biomass materials to construct photonic bandgap materials has attracted increasing attention due to their environmental friendliness. In this work, we introduced biodegradable cellulose acetate to the interstice of hollow silica 3D photonic crystals (PCs) for building hollow silica opals/cellulose acetate nanocomposite films. In the films, the hollow silica 3D PCs offered well-ordered arrays for producing structural colors. Cellulose acetate with excellent film forming ability served as a matrix endowing the PCs frameworks with mechanical stability, including flexibility, robust tensile strength and the ability of repetitive bending. The prepared colored composite films possessed high transparency and can work as anti-counterfeiting labels for banknotes when patterned by a facile mask method. Compared with other reported PCs which are responsive to external stimuli in the field of anti-counterfeiting, these films have the advantage of quick color-transparency switching just by changing the viewing angle. Except for application in security materials, the colored composite films also showed potential as package materials due to their biodegradability. [ABSTRACT FROM AUTHOR]

High-performance one-dimensional photonic crystal coatings that sustain vivid structural colors under a variety of harsh mechanical conditions are fabricated using atomic layer deposition (ALD). By facilely controlling the thickness of the periodic layer, a series of photonic coatings with vivid structural colors ranging from purple, green, yellow, orange to red are obtained. By utilizing surface chemical adsorption and reaction characteristics of ALD process, these photonic crystal coatings exhibit high hardness, brightness, good substrate adhesion and strong mechanical robustness under cyclic tape peels (929 N m−1 adhesion strength, 100 times) and rubbing (50 kPa load pressure, 100 times), respectively. More importantly, they can even withstand high-speed jet impact (at least 20 m s−1, 30 min), particle erosion (200 rpm, 20 min), as well as continuous light irradiation. Given such impressive characteristics, these photonic crystal coatings would find promising applications in our daily life such as in consumer electronics, textiles, the automobile industry, and pigments. [ABSTRACT FROM AUTHOR]

Shape memory photonic crystals (SMPCs), which integrate two distinct scientific areas of photonic crystals and shape-memory polymers, have great potential in advanced optical devices, sensing and displays. Despite recent progress in SMPCs, the contact-stimuli during recovery limit their practical application. Herein, a new type of near-infrared laser-responsive SMPCs is reported. These SMPCs exhibit high optical reversibility, excellent stability, and the direct-pressure-induced programming and near-infrared laser (980 nm)-triggered recovery capabilities, due to the presence of polyurethane units, reversible plastic deformation and the photothermal effect. By taking advantage of these characteristics, various rewritable and stable photonic patterns can be created by imprinting lithography and near-infrared laser writing. Particularly, the photonic membrane exhibits two-way rewritable capability through which the photonic patterns can be created twice in one write/erase cycle. Given the striking color changes associated with the reversible photonic microstructure transitions during programming and recovery, this work provides a facile and versatile platform for multifunctional sensing, displays, and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

This work presents the fabrication of rewritable and highly stable photonic patterns with high spatial resolution and applications in data storage and display panels, based on direct-pressure-programmed polyethylene glycol diacrylate (PEGDA) and polyurethane acrylate (TAPU) copolymer shape memory photonic crystals (SMPCs). Because of the existence of cross-linked polyurethane units and reversible plastic strain on the nanoscale, PEGDA-co-TAPU SMPCs exhibit high optical reversibility, excellent stability, and direct pressure-induced programming ability at room temperature. By taking advantage of these characteristics, various rewritable and highly stable photonic patterns are accurately fabricated at high resolution via imprinting lithography under ambient conditions. Notably, multiple optical microarray patterns can be created by sequential imprinting. These created photonic patterns are used as novel optically readable media for optical data storage and display panels by designing macro/microstructures. The SMPCs provide a new optical platform for the fabrication of rewritable and highly stable photonic patterns. Meanwhile, we anticipate that these photonic patterns could be further extended to the development of reusable photonic devices and sensors. [ABSTRACT FROM AUTHOR]

The synthesis, surface ligand stripping, and infrared optoelectronic device application of NaYF4:Yb,Er–MoS2 nanocomposites are reported. NaYF4:Yb,Er–MoS2 film shows an unusual negative infrared photoresponse after SOCl2/DMF treatment, which exhibits more than two times the photoresponsivity of pure NaYF4:Yb,Er, showing great potential for the development of novel infrared optoelectronic devices. [ABSTRACT FROM AUTHOR]

Here we elucidate the “cooperative effect” of carboxylic acid/amine on the size, shape, and multicolor output of fluoride upconversion nanoparticles (UCNPs) utilizing the amidation reaction. During the synthesis of NaYF4UCNPs using oleic acid (OA) and octadecylamine (OM) as ligands, the evolution of the reaction solution was monitored by FT-IR and proton nuclear magnetic resonance (1H-NMR) spectroscopy. It is shown that N-octadecyloleamide (OOA) was formed and tightly bonded to the surface of the fluoride UCNPs. FT-IR and 1H-NMR analyses point towards a two-step OOA formation mechanism where OA initially reacted with OM to form an acid–base complex (C17H33CO2− +NH3C18H37) in reaction mixture, which further transformed into OOA before the nucleation of fluoride UCNPs at elevated temperature. Importantly, we find that the interaction of OOA with the surfaces of the fluoride UCNPs was stronger than that of OM, and that OOA could strongly quench the green-emitting levels of excited Er3+ions. A series of control experiments and analyses demonstrate that OOA was not only responsible for the control of the size and shape of NaYF4: 20% Yb, 2% Er UCNPs, but also for the multicolor tuning of them. Those observations reveal that the “cooperative effect” between carboxylic acid and amine results from the amidation reaction and its product. This paper provides us with some new deep insights into the “cooperative effect” of carboxylic acid and amine during the synthesis of inorganic nanoparticles under thermolysis. Furthermore, other lanthanide-ion doped fluoride UCNPs with controlled size, shape and multicolor output can also be obtained in the same way. [ABSTRACT FROM AUTHOR]

A simple and general method is reported to tune the multicolour output of lanthanide-ion doped NaYF4upconversion nanoparticles within a given composition by controlling the reaction temperature in the thermolysis procedure. [ABSTRACT FROM AUTHOR]

The synthesis, surface ligand stripping, and infrared optoelectronic device application of NaYF4:Yb,Er-MoS2 nanocomposites are reported. NaYF4:Yb,Er-MoS2 film shows an unusual negative infrared photoresponse after SOCl2/DMF treatment, which exhibits more than two times the photoresponsivity of pure NaYF4:Yb,Er, showing great potential for the development of novel infrared optoelectronic devices.

A general and facile approach for tailoring the multicolor output and shapes of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) within a given composition is presented. By adjusting the temperature and time in the thermolysis procedure, the color output and shapes of NaYF(4):20%Yb, 2%Er UCNPs can be readily manipulated. The nanoparticles were characterized through the use of transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and upconversion luminescence spectroscopy. It is shown that the relative intensities of green emissions gradually increased with the rise of temperature and prolongation of growth time under excitation of 980 nm, which resulted in multicolor output of NaYF(4):20%Yb, 2%Er UCNPs. Simultaneously, the shapes for UCNPs can also be controlled. TEM images, estimated micro-stress by Williamson-Hall methodology and a series of control experiments and analyses reveal that crystallinity is mainly responsible for the multicolor output of UCNPs. Based on the above method, the tailoring of color output is also successfully realized in Ho(3+) and Tm(3+) ions. It is expected that this method may be used to tune the physical properties of other nanoparticles, and these multicolored UCNPs are promising for applications in multiplexed bioimaging, biodetection, display, other optical technologies, etc., (© The Royal Society of Chemistry 2011)