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Lead-free all-inorganic halide materials with different Mn2+-based crystal structures (Cs3MnBr5 and CsMnBr3) were obtained using a convenient synthetic method. Cs3MnBr5 had a bright green emission (522 nm), with a unique single-exponential lifetime (τavg = 236 µs) and a high photoluminescence quantum yield (82 ± 5%). A red emission was observed in the case of the CsMnBr3 structure with a two-exponential fluorescence decay curve, and the lifetime was 1.418 µs (93%) and 18.328 µs (7%), respectively. By a judicious tuning of the synthetic conditions, a mixed phase of Cs3MnBr5/CsMnBr3 was also produced that emitted white light, covering almost the entire visible spectrum. White-light-emitting diodes (WLEDs) with color coordinates (0.4269, 0.4955), a color temperature of (3773 K), and a color rendering index (68) were then fabricated using the as-prepared powder of mixed phases of Cs3MnBr5/CsMnBr3 with a commercial UV LED chip (365 nm). [ABSTRACT FROM AUTHOR]

A novel fabrication of Y 2 O 3 :Tm,Yb translucent ceramics by sintering method using synthetic YF 3 :Tm,Yb microtube powders was reported for the first time. The experimental results showed that the full dense microstructure could be obtained with grain size of about 2 μm. The obtained Y 2 O 3 :Tm,Yb ceramics had less pores and high optical transparency. By using a 980 nm diode laser as the pumping source, the Y 2 O 3 :Tm,Yb ceramics gave intense blue and red upconversion luminescence emissions, which were ascribed to the radiative transitions of 1 G 4 → 3 H 6, 1 G 4 → 3 F 4 and 3 F 2,3 → 3 H 6 of Tm 3+ ions, respectively. The dependence of upconversion emission intensity on the excitation power was examined, and the possible upconversion mechanisms had been proposed accordingly. [ABSTRACT FROM AUTHOR]

In this paper, the enhanced photoluminescence from CdS thin film with SiO2 nanopillar array (NPA) was demonstrated. The CdS was prepared using chemical bath deposition in a solution bath containing CdSO4, SC(NH2)2, and NH4OH. The SiO2 NPA was fabricated by the nanosphere lithography (NSL) techniques. The nanopillar is about 50 nm in diameter, and the height is 150 nm. As a result, the sample with NPA shows an obvious improvement of photoluminescence (PL), compared with the one without NPA. In addition, we also observed that the PL intensity is increased ~5 times if the active layer is deposited on the nanopillar arrays and covered by a thin metal film of Al. It is noteworthy that the enhancement of photoluminescence could be attributed to the roughness of the surface, the 2D photonic band gap (PBG) effect and the surface plasmon resonance (SPR) effects. [ABSTRACT FROM AUTHOR]

Abstract: This work reports the observation of emissions at 2.9μm, 1.8μm and 1.47μm from Dy3+/Tm3+ codoped fluorophosphate glass upon excitation of a conventional 800nm laser diode. Judd–Ofelt intensity parameters and radiative properties of Dy3+ ions in present glasses were calculated using the Judd–Ofelt theory. The mechanism and microparameters of energy transfer processes were investigated based on photoluminescence performance and lifetime measurements. The Dy3+/Tm3+ codoped fluorophosphate glass possessing advantageous spectroscopic characteristics as well as excellent thermal stability is a promising candidate for an efficient 2.9μm laser. [Copyright &y& Elsevier]

Abstract This work reports the plasmon enhanced near-infrared emission from Er3+-doped Bi 2 O 3 -B 2 O 3 -SiO 2 glass prepared by conventional melt-quenching method. The silver nanoparticles (NPs) were introduced into glass host as starting constituent not in the form of silver univalent ions, avoiding the complex energy transfer between Ag+ and Er3+. TEM images analysis reveal the homogeneous distribution of almost spherical Ag NPs with average diameter ~6 nm in amorphous glass. Surface plasmon resonance (SPR) band was observed around 495 nm. Interestingly, the near-infrared emission intensity assigned to Er3+:4I 13/2 →4I 15/2 transition undergoes significant enhancements up to 2 times. The peak emission cross section at 1.5 µm is estimated to be 7.3 × 10–21 cm2 on the basis of Fuchbauer–Ladenburger equation. Furthermore, the measured lifetime of Er3+:4I 13/2 energy state is prolonged from 1.72 ms to 1.85 ms with the gradual increasing Ag NPs. The silver nanoparticles enhanced near infrared luminescence from bismuth glasses have potential application for optical fiber amplifier. [ABSTRACT FROM AUTHOR]

• Glass-ceramic phosphors with mechanoluminescence properties prepared by glass crystallization. • The mechanoluminescence intensity of the glass ceramic phosphor is proportional to the applied load. • When the same amount of force is applied to the sample several times, the ML strength of the sample becomes a decaying trend. Among the many luminescent materials, mechanoluminescence materials which emit light due to stress, friction, and impact external forces have attracted more and more attention, however, red emission is still a technical challenge. As one of the red activators, Pr3+ has excellent optical properties. In this paper, the basic glass with different Pr3+ doping concentration was prepared by melt-quench technique. A group of B 2 O 3 -Al 2 O 3 -SrO glass ceramics containing SrAl 2 B 2 O 7 crystal structure were prepared by different heat treatment systems, and the photoluminescence and mechanical luminescence spectra were measured. Glass ceramics showed strong orange red photoluminescence. The glass ceramics prepared by glass crystallization method has mechanoluminescence properties and has potential application prospects in high-resolution display imaging stress sensor, optical information storage and artificial skin applications. [ABSTRACT FROM AUTHOR]