RESUMO
The smart materials with multi-color and stimuli-responsive luminescence are very promising for next generation of optical information encryption and anti-counterfeiting, but these materials are still scarce. Herein, a multi-level information encryption strategy is developed based on the polychromatic emission of Sb-doped double perovskite powders (SDPPs). Cs2NaInCl6:Sb, Cs2KInCl6:Sb, and Cs2AgInCl6:Sb synthesized through coprecipitation methods exhibit broadband emissions with bright blue, cyan, and orange colors, respectively. The information transmitted by specific SDPP is encrypted when different SDPPs are mixed. The confidential information can be decrypted by selecting the corresponding narrowband filter. Then, an encrypted quick response (QR) code with improved security is demonstrated based on this multi-channel selection strategy. Moreover, the three types of SDPPs exhibit three different water-triggered luminescence switching behaviors. The confidential information represented by Cs2NaInCl6:Sb can be erased/recovered through a simple water spray/drying. Whereas, the information collected from the green channel is permanently erased by moisture, which fundamentally avoids information leakage. Therefore, different encryption schemes can be designed to meet a variety of encryption requirements. The multicolor and stimuli-responsive luminescence greatly enrich the flexibility of optical information encryption, which leaps the level of security and confidentiality.
RESUMO
A novel multi-color emitting Na2 YMg2 V3 O12 :Sm3+ phosphor was synthesized using a solid-state reaction, and its crystal structure, luminescence properties, and thermal stability were studied. Charge transfer within the (VO4 )3- groups in the Na2 YMg2 V3 O12 host led to a broad emission band between 400 and 700 nm, with a maximum at 530 nm. The Na2 Y1-x Mg2 V3 O12 :xSm3+ phosphors exhibited a multi-color emission band under 365 nm near-ultraviolet (near-UV) light, consisting of the green emission of the (VO4 )3- groups and sharp emission peaks at 570 nm (yellow), 618 nm (orange), 657 nm (red), and 714 nm (deep red) of Sm3+ ions. The optimal doping concentration of Sm3+ ions was found to be 0.05 mol%, and the dipole-dipole (d-d) interaction was primarily responsible for the concentration quenching phenomenon. Using the acquired Na2 YMg2 V3 O12 :Sm3+ phosphors, commercial BaMgAl10 O17 :Eu2+ blue phosphor, and a near-UV light-emitting diode (LED) chip, a white-LED lamp was designed and packaged. It produced bright neutral white light, manifesting a CIE coordinate of (0.314, 0.373), a color rendering index (CRI) of 84.9, and a correlated color temperature (CCT) of 6377 K. These findings indicate the potential of Na2 YMg2 V3 O12 :Sm3+ phosphor to be used as a multi-color component for solid-state illumination.
Assuntos
Iluminação , Luminescência , Sódio , Raios Ultravioleta , TemperaturaRESUMO
Bi3+, Eu3+ co-doped Ba2Y2Si4O13 phosphors with multi-color luminescence properties were prepared by high temperature solid state method. The structure, luminescent properties and temperature characteristics were studied by X-ray diffraction, scanning electron microscope, fluorescence spectrum and temperature-dependence of emission spectrum. Ba2Y2Si4O13: Bi3+, Eu3+ phosphors can emit color from cyan to red when the excitation wavelength was changed from 340 nm to 390 nm, which is attributed to that there are two Bi3+ ion emission centers, and their emission intensity will change with the change of excitation wavelength. Moreover, the emission of the phosphor has good temperature sensing characteristics, based on the fluorescence intensity ratio of the two blue emission bands of Bi3+ and the red emission peak of Eu3+, a multimode thermometer with high temperature sensitivity was constructed. At the same time, based on the dynamic luminescence characteristics of the phosphor, the dynamic anti-counterfeiting experiments are designed. Therefore, the results show that the material has a bright prospect in the field of temperature sensing and anti-counterfeiting.