Information encryption is an important means to improve the security of anti-counterfeiting labels. At present, it is still challenging to realize an anti-counterfeiting label with multi-function, high security factor, low production cost, and easy detection and identification. Herein, using inkjet and screen printing technology, we construct a multi-dimensional and multi-level dynamic optical anti-counterfeiting label based on instantaneously luminescent quantum dots and long afterglow phosphor, whose color and luminous intensity varied in response to time. Self-assembled quantum dot patterns with intrinsic fingerprint information endow the label with physical unclonable functions (PUFs), and the information encryption level of the label is significantly improved in view of the information variation in the temporal dimension. Furthermore, the convolutional residual neural networks are used to decode the massive information of PUFs, enabling fast and accurate identification of the anti-counterfeit labels.

ZnSe/ZnS core/shell quantum dots (QDs) are environmental‐friendly blue light‐emitting material, which can easily achieve deep blue emission upon external excitation. However, its deep valence band (VB) and numerous defect states remain handicap to realize sufficient performance of quantum dot light‐emitting diodes (QLEDs). In this work, high‐performance cadmium‐free ZnSe/ZnS QLEDs by constructing a double organic hole‐transport layer (HTL) to obtain carrier balance are presented. The double HTLs, which consist of poly(9,9‐dioctylfluorene‐co‐N‐(4‐butylphenyl)diphenylamine) (TFB) and 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT), can suppress the accumulation of electrons between the HTL and the emissive layer (EML), leading to more hole and electron recombination luminescence in QD layer. In addition, the C8‐BTBT layer is conducive to improve the uniformity of QDs film. Thus, the resulting device achieves an external quantum efficiency of 7.23% with TFB/C8‐BTBT double HTLs, which is almost 150% higher than that of traditional devices based on a single hole‐transport layer (4.84%). The authors anticipate that these results can provide a guidance for the optimization of cadmium‐free blue QLEDs.

With tunable emission in the full visible region, the ecofriendly InP quantum dots (QDs) show unique application prospects in light-emitting devices. At present, InP QDs suffer from wide-bandwidth emission, especially for electroluminescence (EL), which hinders their applications in high-performance display devices. Here, we report a facile one-pot synthesis of narrow-bandwidth InP/ZnSeS/ZnS QDs using a safe phosphorus source of tris­(dimethylamino)­phosphine, in which the ZnSeS inner-shell layer is formed via temperature-gradient solution growth from 240 to 280 °C. The synthesized green QDs have a high photoluminescence quantum yield (PLQY) of 91% and full width at half-maximum (fwhm) of 36 nm. Moreover, the resultant quantum dot light-emitting devices (QLEDs) also show a narrow fwhm of 42 nm, which is the narrowest emission of green InP QLEDs based on a safe phosphorus source reported so far. Further modulation of the electron injection into the device by inserting a thin layer of lithium fluoride results in a peak external quantum efficiency of 5.56%.

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Epoxy resin-modified asphalt binder (ERMAB) has been wildly used in the pavement of steel bridges, while the improvement on its low temperature is still a big challenge to researchers. This paper tries to improve the low-temperature performance of ERMAB by optimizing the modifier, epoxy resin. Firstly, three epoxy resins and three amine curing agents were prepared and used for the modification of asphalt binders. Secondly, the formula and prepared methods of ERMABs were optimized and determined through compatibility, viscosity growth rate, and tensile tests. Thirdly, an overall comparison on the phase structure, thermal stability, low-temperature performance, temperature and frequency dependence, and fatigue performance of prepared ERMABs and control sample were made. Results show that polyurethane-modified epoxy resin or dimer acid-modified epoxy resin, with a suitable curing agent, can significantly improve the low-temperature performance of ERMAB, and the curing time meets the construction requirements. Compared with the control sample, the two ERMABs have basically the same rheological properties at medium temperature, but slightly worse high-temperature performance and fatigue resistance. The significance of this paper lies in proposing a feasible way to improve the low-temperature performance of ERMAB.