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Anticounterfeiting technologies meet challenges in the Internet of Things era due to the rapidly growing volume of objects, their frequent connection with humans, and the accelerated advance of counterfeiting/cracking techniques. Here, we, inspired by biological fingerprints, present a simple anticounterfeiting system based on perovskite quantum dot (PQD) fingerprint physical unclonable function (FPUF) by cooperatively utilizing the spontaneous-phase separation of polymers and selective in situ synthesis PQDs as an entropy source. The FPUFs offer red, green, and blue full-color fingerprint identifiers and random three-dimensional (3D) morphology, which extends binary to multivalued encoding by tuning the perovskite and polymer components, enabling a high encoding capacity (about 108570000, far surpassing that of biometric fingerprints). The strategy is compatible with mainstream production techniques that are widely used in traditional low-cost printed anticounterfeiting labels including spray printing, stamping, writing, and laser printing, avoiding complicated fabrication. Macrographical patterns and micro/nanofingerprint patterns with multiscale-tailorable inter-ridge sizes can be fused into a single FPUF label, satisfying different levels of anticounterfeiting requirements. Furthermore, a smart fused scheme of enhanced deep learning and fingerprint characteristic comparison is leveraged, by which high-efficiency, high-accuracy authentication of our FPUFs is achieved even for the increasingly huge FPUF databases and imperfectly captured images from users.

Photosynthesis in nature has been deemed as the most significant biochemical reaction, which maintains a relatively stable content of O2and CO2in the atmosphere. Herein, for a deeper comprehension of natural photosynthesis, an artificial photosynthesis model reaction of photochemical CO2to CO conversion (CO2+2 H++ 2e−→ CO + H2O) catalyzed by a homogeneous hexanuclear ring cobalt complex {K2[CoO3PCH2N(CH2CO2)2]}6(Co6complex) is developed. Using the [Ru(bpy)3]2+as a photosensitizer and TEOA as a sacrificial electron donor, an optimal turnover frequency of 503.3 h−1and an apparent quantum efficiency of 0.81% are obtained. The good photocatalytic CO2reduction performance is attributed to the efficient electron transfer between Co6complex and [Ru(bpy)3]2+, which boosts the photogenerated carriers separation of the photosensitizer. It is confirmed by the j-Vcurves, light-assisted UV-vis curves, steady-state photoluminescence spectra and real-time laser flash photolysis experiments. In addition, the proposed catalytic mechanism for CO2reduction reaction catalyzed by the Co6complex is explored by the potassium thiocyanate poison experiment, Pourbaix diagram and density functional theory calculations.

Photosynthesis [6CO2 + 12H2O → (CH2O)6 + 6O2 + 6H2O] in nature contains a light reaction process for oxygen evolution and a dark reaction process for carbon dioxide (CO2) reduction to carbohydrates, which is of great significance for the survival of living matter. Therefore, for simulating photosynthesis, it is desirable to design and fabricate a bifunctional catalyst for promoting photocatalytic water oxidation and CO2reduction performances. Herein, a molecular confined synthesis strategy is reasonably proposed and applied, that is the bifunctional CoOx/Co/C-T (T= 700, 800 and 900 °C) photocatalysts prepared by the pyrolysis of molecular Co-EDTA under N2and air atmosphere in turn. Among the prepared photocatalysts, the CoOx/Co/C-800 shows the best photocatalytic water oxidation activity with an oxygen yield of 51.2%. In addition, for CO2reduction reaction, the CO evolution rate of 12.6 μmol/h and selectivity of 75% can be achieved over this catalyst. The improved photocatalytic activities are attributed to the rapid electron transfer between the photosensitizer and the catalyst, which is strongly supported by the current density-voltage (j-V), steady-state and time-resolved photoluminescence spectra (PL). Overall, this work provides a reference for the preparation and optimization of photocatalysts with the capacity for water oxidation and CO2reduction reactions.