Search

The In‐based double perovskite halides have been widely studied for promising optical‐electric applications. The halide hexagonal perovskite Cs2LiInCl6 was isolated using solid‐state reactions and investigated using X‐ray diffraction and solid‐state NMR spectra. The material adopts a 12‐layered hexagonal structure (12R) consisting of layered cationic orders driven by the cationic charge difference and has Li+ cations in the terminal site and In3+ in the central site of face‐shared octahedron trimers. Such a cationic ordering pattern is stabilized by electrostatic repulsions between the next‐nearest neighboring cations in the trimers. The LiCl6 octahedron displays large distortion and is confirmed by 7Li SS NMR in the Cs2LiInCl6. The Cs2LiInCl6 material has a direct bandgap of ~4.98 eV. The Cs2LiInCl6: Mn2+ displays redshift luminescence (centered at ~610–622 nm) from the substituted Mn2+ emission in octahedron with larger PLQY (17.8 %–48 %) compared with that of Cs2NaInCl6: Mn2+. The Mn‐doped materials show luminescent concentration quenching and thermal quenching. The composition Cs2Li0.99In0.99Mn0.02Cl6 exhibits the highest PL intensity, a maximum PLQY of 48 %, and high luminescent retention rate of ~86 % below 400 K and is suitable for application for pc‐LED. These findings contribute to our understanding of the chloride perovskites and hold potential for widespread optical applications. [ABSTRACT FROM AUTHOR]

Ultraviolet-C light has significant application prospects in the fields of disinfection, air purification, etc. Herein, an effective UVC upconversion phosphor Y2SiO5:Pr3+ was successfully prepared, as evidenced by the XRD results. The diffuse reflection spectra of Y2SiO5: Pr3+ phosphors presented two distinct absorption bands corresponding to the electron transitions of 3H4 → 3P2 and 3H4 → 1D2, and the Eg was determined to be 4.22 eV for the Y2SiO5 host, which is very close to the Eg (4.172 eV) calculated by DFT. Under the excitation of 460 nm laser, two emission peaks centered at ~247 nm and ~ 258 nm were found in the range of 230-280 nm, which are attributed to the transitions of 4f5d → 3H4 and 4f5d → 3H5 of Pr3+ ions. With the help of temperature-dependent emission spectra, the phosphor demonstrated impressive thermal stability up to 150 °C. These findings indicate that the Y2SiO5: Pr3+ phosphor has the potential application in disinfection. [ABSTRACT FROM AUTHOR]

Solid-state optical functional materials play an extremely important role in major projects. Herein, a series of the Ce3+-doped Ga2O3-Gd2O3-Al2O3-SiO2-Na2O were successfully prepared by conventional melt-quenching method. The investigation showed that the densities of glasses presented a monotonically increasing trend, while the variation trend of molar volume was opposite. Structural analysis showed that the glass network was mainly composed of [SiO4] tetrahedral functional groups. From the optical absorption data, the optical band gap and Urbach energy were calculated. Under the excitation of 367 nm light, the glasses exhibited a strong broadband in the range of 380-700 nm. As the temperature rises to 150 °C, the integrated luminescent intensity of the glass gradually decreased to 61% of that at 30 °C. In addition, the fluorescence lifetimes of glasses were approximately 4.5 µs. The excellent photoluminescence properties shows that these glass has potential applications in optical functional materials, such as lighting and display field. [ABSTRACT FROM AUTHOR]

The doping of transition metal ions in the up‐conversion (UC) luminescent material doped with Yb3+/Ln3+ is a facile way to increase their UC luminescence intensities and alter their colors. In this study, La2MgTiO6:Yb3+/Mn4+/Ln3+ (Ln3+ = Er3+, Ho3+, and Tm3+) phosphors showing excellent luminescence properties were prepared by a solid‐state method. The sensitivity of the La2MgTiO6:Yb3+/Ln3+/Mn4+ phosphor was double that without Mn4+, because Mn4+ affects the UC emissions of Ln3+ via energy transfer between these ions. Moreover, Mn4+ also acts as a down‐conversion activator, which can combine with UC ions to achieve multi‐mode luminescence at different wavelengths. Under 980 nm excitation, these samples emit green light (from Er3+ and Ho3+) and blue light (from Tm3+). In contrast, under 365 nm excitation, they emit red light (from Mn4+). Further testing revealed that the La2MgTiO6:Yb3+/Mn4+/Ln3+ phosphors have potential applications in temperature sensing and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

W-LED lighting is a green and environment-friendly lighting method in today's society, and red phosphors play an irreplaceable role in W-LED lighting. In this work, a series of rare-earth-doped phosphors, Ba2-aSiO4: aEu3+ (a = 0.02 ~ 0.10), Ba2-a-bSiO4: aEu3+, bBi3+ (b = 0.01 ~ 0.08) and Ba2-a-cSiO4: aEu3+, cSm3+ (c = 0.005 ~ 0.02), were successfully synthesized by traditional high-temperature solid-state reaction method. The experimental results showed that the concentration quenching occurred in the case of the doping concentration of Eu3+ exceeding 0.08 mol, and the main mechanism of concentration quenching was based on the multipole interaction. Under the excitation of 392 nm light, all phosphors emitted strong reddish orange light. The doping of Sm3+ and Bi3+ ions can effectively improve the luminescence properties of Ba2-aSiO4: aEu3+ phosphor, and the optimal doping concentration for Bi3+ and Sm3+ ions was 4 mol.% and 1 mol.%, respectively. The results mentioned above indicate that these phosphors have a potential application in the W-LED field. [ABSTRACT FROM AUTHOR]

Tricolor phosphors play a pivotal role in the application of white-light-emitting diode (W-LED). Herein, we successfully prepared a series of Y2Zr2O7:Eu3+ phosphors via sol–gel method. Structural analysis showed that the phosphor was fluorite structure (space group Fm–3 m), and the elements of Y, Zr, O, and Eu were uniformly distributed within each particle. From the emission spectra, five distinctive peaks can be found in the wavelength of 500–700 nm excited by 393 nm UV light, and in the case of increase of Eu3+ contents, the luminescence intensities of phosphors increased first and then decreased. And the chromaticity coordinates fell into the reddish orange zone. For different calcination temperatures, they did not seriously affect the crystal structure, chromaticity coordinates, and CCTs except for crystallinity. Meanwhile, the phosphor has excellent thermal stability at working temperature of 150 °C. The above-mentioned excellent properties indicate that this phosphor has potential applications in W-LED devices. [ABSTRACT FROM AUTHOR]

The doping of transition metal ions in the up‐conversion (UC) luminescent material doped with Yb3+/Ln3+ is a facile way to increase their UC luminescence intensities and alter their colors. In this study, La2MgTiO6:Yb3+/Mn4+/Ln3+ (Ln3+ = Er3+, Ho3+, and Tm3+) phosphors showing excellent luminescence properties were prepared by a solid‐state method. The sensitivity of the La2MgTiO6:Yb3+/Ln3+/Mn4+ phosphor was double that without Mn4+, because Mn4+ affects the UC emissions of Ln3+ via energy transfer between these ions. Moreover, Mn4+ also acts as a down‐conversion activator, which can combine with UC ions to achieve multi‐mode luminescence at different wavelengths. Under 980 nm excitation, these samples emit green light (from Er3+ and Ho3+) and blue light (from Tm3+). In contrast, under 365 nm excitation, they emit red light (from Mn4+). Further testing revealed that the La2MgTiO6:Yb3+/Mn4+/Ln3+ phosphors have potential applications in temperature sensing and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]