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The remote and non-invasive optical thermometer exploiting fluorescence intensity ratio technology is of great importance in various intelligent optoelectronic sensors. Dual-emitting YNbO 4 :Bi3+, Eu3+ phosphor is synthesized and investigated for the development of temperature sensing materials. The phosphor excited at 318 nm shows a blue broad band emission and several red sharp peaks. The value of Bi3+→Eu3+ energy transfer can reach 98.2% when Eu3+ doping content is 0.14. Benefiting from diverse thermal response behaviors due to Bi3+ and Eu3+ ions completely different electronic configurations, a dual-emitting optical thermometer is designed. The maximum values of absolute and relative sensitivities are as high as 2.51% K−1 at 473 K and 1.43% K−1 at 423 K, respectively. The thermochromic phosphor possesses a great chromaticity shift (ΔE = 317×10−3) with temperature. Based on superior color discriminability, visual colorimetry temperature measurement relied on thermal characteristic is proposed. All the results demonstrate that YNbO 4 :0.01Bi3+, 0.005Eu3+ phosphor as a sensitive and reliable optical thermometer has great potentials in temperature measurement. [ABSTRACT FROM AUTHOR]

Abstract: N–Al co-doped ZnO films with various thicknesses were deposited on glass substrates by ultrasonic spray pyrolysis (USP). The crystalline microstructure, morphology, distribution of elements and photoluminescence properties of ZnO films were characterized by X-ray diffraction (XRD), field emission scanning microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectroscopy. The XRD and FESEM results show that with the increase of film thickness the grain size increases and the grain shape changes from regular hexagonal sheet-like to wedge-shaped, even pyramidal. The PL spectra illustrate that there is an obvious red-shift for the emission center from ultraviolet to blue region, and the intensities of defects emissions increase with the increase of thickness. In addition, the electrical properties are proved to be strongly affected by film thickness. [ABSTRACT FROM AUTHOR]

Researches on tunable luminescence and temperature sensitivity of phosphors have become an increasingly popular trend. This paper reports a series of Ca 2 YZr 2 Al 3 O 12 (CYZA):Bi3+, Sm3+ phosphors prepared by solid-state reaction. The phase purity, energy transfer, luminescent properties and temperature sensing performance of the phosphors have been carefully studied. CYZA:Bi3+, Sm3+ phosphors excited by ultraviolet light show tunable color emission, and the color shifts from dark blue to pink due to Bi3+→Sm3+ energy transfer. The related luminescent mechanism of phosphors is also explained. In addition, according to the different thermal sensitivity of Bi3+ and Sm3+, the temperature sensitivity of the phosphors is studied by fluorescence intensity ratio model. The maximum values of absolute sensitivity and relative sensitivity reach up to 0.099% K−1 at 423 K and 0.356% K−1 at 473 K, respectively. These findings indicate that CYZA:Bi3+, Sm3+ phosphors are potential candidates for tunable luminescence and temperature sensing. • The color-tunable property can be obtained in CYZA:Bi3+, Sm3+ phosphors. • Energy transfer from Bi3+ to Sm3+ ions. • Different thermal attenuation behaviors of Bi3+ and Sm3+ ions. • Temperature sensing performance is investigated by FIR model. [ABSTRACT FROM AUTHOR]

Abstract: Indium-doped ZnO transparent conductive thin films were deposited on glass by ultrasonic spray pyrolysis (USP) to investigate the influence of various acids on the physical properties. The ZnO:In films were polycrystalline with (002) preferred orientation with various acids addition except for films with acetic acids. The film morphologies changed substantially with different acids in the precursor solutions. Compared with organic acids, films prepared with inorganic acids exhibited better crystal quality and stronger near-band-edge emission (NBE). The films with acetic acid addition obtained the lowest resistivity, highest mobility and carrier concentration due to the formation of compounds among acetate and metal cations. The resistivity reached as low as 6.7×10−3 Ωcm with a maximum mobility of 24.7cm2 V−1 S−1 and a minimum carrier concentration of 2.36×1019 cm−3 by tuning acetic acid concentration to 1.5M. [Copyright &y& Elsevier]

The poly(butylene adipate- co -terephthalate) (PBAT)/poly(lactic acid) (PLA) films have been widely used due to their biological degradability and excellent comprehensive properties. However, the reports regarding biodegradable PLA/PBAT films are rather scarce. In this work, systematical investigations of biaxially stretched PLA/PBAT films were performed. Compared with unstretched films, the PLA/PBAT 75/25 films with the stretching ratio of 5 × 1 exhibited an improvement on the crystallinity of PLA from 6 % to 58.6 %. According to 2D-WAXS results, the orientation of the α crystal in the MD increased with the increase of the stretching ratio. The stretched films showed favorable barrier properties. The oxygen permeability (OP) of 2 × 2 PLA/PBAT 75/25 films shows a decrement of 22 % compared with that of the unstretched films. Interestingly, the uniaxially stretched PLA/PBAT 75/25 films exhibits increased surface roughness (Ra) for 3 × 1 film whereas decreased Ra for the 5 × 1 film, which could be related to the phase separation under stretching. The tensile strength in the machine direction (MD) of the PLA/PBAT 75/25 films was improved up to 51.6 MPa for 5 × 1 film, which is 45 % higher than that of unstretched counterpart. The stretched films exhibit excellent mechanical and barrier properties, which could be utilized in packaging industry with high potential. [ABSTRACT FROM AUTHOR]