LAUSR

Recently, the growing demands for optical anti-counterfeiting technology has motivated intensive research in newly-emerging halide perovskite quantum dots (QDs). However, the poor stability and unsatisfactory fluorescence efficiency of such materials are the main obstacles to the application of reliable anti-counterfeiting. In this work, we performed a well-controlled investigation of the effect of surfactant (ʟ-α-phosphatidylcholine, LP) and silica encapsulation on the stability and emission of the CsPbBr3 QDs. Because of the synergetic effect of surfactant and core/shell configuration, the resulting CsPbBr3/LP/SiO2 QDs composites demonstrated a higher photoluminescence quantum yield (>90%), a better color purity, and a significantly improved stability to heat, ultraviolet light, water and ambient oxygen, which provides the basic conditions as a high-tech security ink for anti-counterfeiting. By the ink jet printing technology, we demonstrated that our CsPbBr3/LP/SiO2 QDs composites can act as a smart concealed ink for information encryption and decryption. More importantly, the anti-counterfeiting effect can be efficiently sustained even though the paper with designable patterns was crudely treated by water soak, heating/cooling cycling, and continuous ultraviolet light switching (1500 cycles). The above results obtained provide effective strategies to improve emission efficiency and stability of perovskite QDs, thereby endue them in the anti - counterfeiting application potential.