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Inorganic chiral materials have attracted increasing attention due to their application prospects. In this work, we synthesized the chiral nanostructured bismuth oxychloride co‐doped with Er3+/Yb3+ phosphor (D‐BYEP) by hydrothermal growth with a subsequent air‐annealing strategy using chiral sugar alcohols as the chiral inducer. The D‐BYEP emitted bright red light under the excitation of 980 nm near‐infrared laser. The temperature sensing behavior was evaluated by employing the thermally coupled (TCLs) or non‐thermally coupled (NTCLs) levels of Er3+. The maximum relative sensitivities (SR) obtained are 0.84% K−1 and 1.30% K−1 (298 K), respectively. The results show that the D‐BYEP may be ideal candidates for optical temperature sensors. We anticipate that this new type of inorganic chiral phosphor may have a range of applications in temperature measurement of light sources. [ABSTRACT FROM AUTHOR]

Non‐toxic halide double perovskite materials have many advantages of lead halide perovskite. Whereas, they usually exhibit poor stability and very low intrinsic photocatalytic CO2 reduction activity due to the insufficient separation of photogenerated charges and the lack of active sites. In this work, stable chlorine‐deficient 3D hierarchical Cs2NaBiCl6 porous microspheres assembled by highly crystalline nanoflakes were prepared by a simple grinding method. An unprecedented CO yield of 30.22 µmol g−1 h−1 was achieved in the gas‐solid photocatalytic reduction of CO2 without sacrificial agents, which is the highest value among lead‐free halide perovskite photocatalysts. Experimental results and density‐functional theory calculations show that the chlorine vacancy plays the triple role of suppressing photogenerated electron‐holes recombination, enhancing CO2 adsorption, and significantly reducing the free energy barrier for the key intermediate COOH* generation. In comparison with the pristine Cs2NaBiCl6, coupling of surface and defect engineering of the hierarchical sample brings 12.34 times enhancement of CO2 photoreduction activity. This work proposes a simple method to synthesize a chlorine‐vacancy rich 3D hierarchical lead‐free halide perovskite and offers a new design idea to substantially enhance the photocatalytic activity, opening a door for the prospective contribution of these materials to carbon neutralization. [ABSTRACT FROM AUTHOR]

It has been an urgent need for developing a new bright long‐wave emitting phosphor to improve the color rendering index (CRI) of white light‐emitting diodes (WLEDs). Here, based on the concept of oxygen vacancy‐induced long‐wave emission by Bi3+ doping, we selected BaSrGa4O8 as the matrix, which has a low‐dimensional chain structure that can produce enough oxygen vacancies. After the introduction of Bi3+, orange emission was successfully achieved. To further improve the luminescence efficiency, the system of BaSrGa4O8:Bi3+,K+ was designed. Interestingly, although significant emission enhancement was obtained, the material showed reduced absorption with increased oxygen vacancies. More detailed experimental evidences confirm that oxygen vacancies can activate Bi3+ to achieve long‐wave emission. Our results provide a new way to design Bi3+‐based long‐wave emitting phosphors with low‐dimensional crystal structure. Finally, a WLED device containing BaSrGa4O8:Bi3+,K+ was fabricated and exhibited an enhanced CRI, which shows a promising application in WLEDs. [ABSTRACT FROM AUTHOR]

Cr3+‐doped phosphors have recently gained attention for their application in broadband near‐infrared phosphor‐converted light‐emitting diodes (pc‐LEDs), but generally exhibit low efficiency. In this work, K2Ga2Sn6O16:Cr3+ (KGSO:Cr) phosphor was designed and synthesized. The experimental results show that the Cr3+‐doped phosphor exhibited broadband emissivity in the range 650‐1300 nm, with a full width at half maximum (FWHM) of approximately 220‐230 nm excited by a wavelength of 450 nm. With the co‐doping of Gd3+ ions, the internal quantum efficiency (IQE) of the KGSO:Cr phosphor increased from 34% to 48%. The Gd3+ ions acted neither as activators nor sensitizers, but to justify the crystal field environment for efficient Cr3+ ions broad emission. The Huang‐Rhys factor decreased as the co‐doping of Gd3+ ions increased, demonstrating that the nonradiative transitions were suppressed. An efficient strategy for enhancing the luminescence properties of Cr3+ ions is proposed for the first time. The Gd3+–co‐doped KGSO:Cr phosphor is a promising candidate for broadband NIR pc‐LEDs. [ABSTRACT FROM AUTHOR]

Series of silver nanoparticles (NPs) embedded CsPbBr3 quantum dots (QDs) glass was synthesized via the melt‐quench method. Ag NPs and CsPbBr3 QDs coexist in the TEM image of the Ag‐doped glass sample. Photoluminescence (PL) spectra show that the 0.1 molar ratio Ag2O‐doped sample had a PL intensity 2.37 times than the undoped sample. This increase is generated by localized surface plasmon resonance coupling between the Ag NPs and CsPbBr3 QDs. Excessive Ag doping weakens the PL intensity due to spectral self‐absorption of the Ag NP surface plasmon resonance (SPR). Self‐adsorption of SPR is detrimental to luminescence properties because it increases the amount of photogenerated charge carriers, which proceed through nonradiative relaxation pathways. In addition, stability results of Ag NP‐doped‐CsPbBr3 QD glass show that they have excellent stability. This study on Ag NP‐doped‐CsPbBr3 QD glass provides a new idea for the future development of perovskite QD optoelectronic devices. [ABSTRACT FROM AUTHOR]

Making illumination light sources become comfortable to the human eye is a long‐term effort, which justifies the current research on warm white‐light‐emitting diodes (w‐LEDs). In this work, a novel phosphor for w‐LEDs, namely SrGa12O19: Dy3+(SGO: Dy3+), with a low‐color temperature (CT) was designed and synthesized. The crystal structure, the luminescence properties, the thermoluminescence properties and the stability of SGO: Dy3+ were investigated. We demonstrate outstanding luminescent characteristics and excellent stabilities. The intensity of emission light keep remained when excited by a flickering light source with a chopping speed or off‐time of a few seconds, which indicates that the SGO: Dy3+ phosphor has anti‐flicker properties that will be useful for potential applications, as LEDs driven by alternating current (AC‐LED). The chromaticity coordinates and the correlated color temperature (CCT) of SGO: Dy3+ phosphors with different Dy3+ concentrations are close with an optimal doping at 4.00 mol% Dy3+ for chromaticity coordinate (0.4269, 0.4348) and a lowest CCT of 3361 K. The perfect weatherability of this phosphor was also confirmed since the phosphorescence intensity and the color were stable at high temperature and in a high humidity environment. The performance obtained shows that SGO: Dy3+ is a suitable candidate for illumination sources that are beneficial to human health. [ABSTRACT FROM AUTHOR]

Fetal weight is an important factor to determine the delivery mode of pregnant women. The change of fetal weight is significant, according to regular health monitoring of pregnant women. Conventional methods of fetal weight estimation, namely those based on B-ultrasound, are very complicated and the costs are high. In this paper, we propose a new method based on body composition. An abdominal four-segment impedance model is first established upon pregnant women, as well as the method of calculation. A body composition based method is then given to estimate the fetal weight, with the solution given explicitly. Analyses of clinical data reveal the smallness of the error between the estimated value and the actual value. The error between B-ultrasound and the present method is less than 15%. [ABSTRACT FROM AUTHOR]

Abstract: Acting as the electron trap, oxygen vacancies can strongly influence the long persistent luminescence (LPL) properties were verified in Ca2Ga2GeO7: Zn2+ (CGGZ) phosphor. The existence of oxygen vacancies in this self‐excitation material was confirmed by a simple fluorescence probe method. The introduction of zinc ions promotes the generation of oxygen vacancies, as well as optimizes its LPL properties. Thermoluminescence (TL) analysis revealed that electrons in deep trap will effectively transfer to the shallow one via the bridge of interstitial zinc. Accordingly, a mechanism for PL and LPL in this Gallogermanates was provided. [ABSTRACT FROM AUTHOR]

Abstract: Acting as the electron trap, oxygen vacancies can strongly influence the long persistent luminescence (LPL) properties were verified in Ca2Ga2GeO7: Zn2+ (CGGZ) phosphor. The existence of oxygen vacancies in this self‐excitation material was confirmed by a simple fluorescence probe method. The introduction of zinc ions promotes the generation of oxygen vacancies, as well as optimizes its LPL properties. Thermoluminescence (TL) analysis revealed that electrons in deep trap will effectively transfer to the shallow one via the bridge of interstitial zinc. Accordingly, a mechanism for PL and LPL in this Gallogermanates was provided. [ABSTRACT FROM AUTHOR]