The three-dimension (3D) flower-like α-Fe 2 O 3 @TiO 2 core-shell nanocrystals with thorhombic, cubic and discal morphologies are synthesized for photocatalytic application. α-Fe 2 O 3 nanocrystals were prepared via Cu 2+ , Zn 2+ and Al 3+ ions-mediated hydrothermal route. The α-Fe 2 O 3 @TiO 2 core-shell nanocrystals are obtained via hydrothermal and annealing process. The shape-dependent photocatalytic activity of these as-obtained α-Fe 2 O 3 @TiO 2 core-shell nanocrystals are measured. The results reveal that the discal α-Fe 2 O 3 @TiO 2 nanocrystals exhibit the best photocatalytic activity than other two core-shell nanocrystals. Because the discal α-Fe 2 O 3 nanocrystals possess more rough surface and surface defects. The fast interfacial charge transfer process and the wide spectral response could be the driving force for the enhanced photocatalytic performance. These core-shell architectures provide a positive example for synthesis of novel composite nanomaterial.

β-NaYF 4 UCMPs are large-scale synthesized, and the UCMPs fluorescence inks-based screen printing patterns are applied for anti-counterfeit application.Abstract: Upconversion materials could be applied for anti-counterfeit fields because of their high concealment and high upconversion fluorescence efficiency. Herein, the different lanthanide ions-doped β-NaYF 4 upconversion micro-particles (UCMPs) with uniform hexagonal morphology were large-scale synthesized (more than 0.5 g) through a facile hydrothermal method. It is very interesting to find out the fluorescence intensity and the eventual morphology of UCMPs are highly dependent on the reaction conditions. Then, the optimal UCMPs with uniform morphology and strong fluorescence intensity were selected as promising candidate for preparing ink.Eventually, we successfully printed designable and multicolor fluorescent patterns on flexible substrates (common paper and polyethylene terephthalate, PET) by using the as-prepared β-NaYF 4 : Yb 3+ , Tm 3+ /Er 3+ /Eu 3+ UCMPs inks. Under ambient conditions, the printed patterns on conventional paper are invisible, while such printed patterns on PET are white color. But all the patterns could perform blue, yellow-green and green fluorescence patterns under the irradiation of 980 nm lasers, respectively, when using β-NaYF 4 : Yb 3+ , Tm 3+ /Er 3+ /Eu 3+ UCMPs inks. We envision that the UCMPs fluorescent inks-based flexible and rapid screen printing patterns have an enormous potential for anti-counterfeit and security applications.

Three-dimension (3D) ZnO/Ag nanowire arrays (NWA) SERS substrates are fabricated by screen printing technique. The preparation of patterned ZnO NWA involves a two-step growth process. The ZnO nanoparticles (NPs)-based ink is prepared and printed as seed layers, which are used as templates to fabricate patterned ZnO NWA via a hydrothermal method. During the screen printing process, the patterns of ZnO NWA are controlled by printing plates. The as-obtained NWA with 2 uniform morphology was fabricated at 90 °C, which exhibit hydrophilic and lipophilic properties.Subsequently, the sensitive 3D SERS substrates are fabricated through deposition of Ag NPs onto the surface of patterned ZnO NWA by magnetron sputtering. The detection limit of Malachite green (MG) can achieve 10 -12 M with an enhancement factor of about 2.5×10 10 . Combined with the sensitivity and uniformity, the ZnO/Ag NWA is applied for the quick detection of low concentrations of molecules related to food safety, such as amoxicillin.