[en] In a typical synthesis, luminescent carbon nanoparticles were synthesized via hydrothermal oxidation of glucose in deionized water. Here we reported the photoluminescence of the carbon nanoparticles greatly enhanced when reacted with Al(NO₃)₃ for the first time, the resulted carbon dots have appropriate spherical morphology, uniform size and good dispersion. The carbon nanoparticles can exhibit excitation-dependent photoluminescence behavior and emit bright green photoluminescence under UV excitation, which might provide a potential application for carbon dots in other extensive fields. - Highlights: • One step synthesis of Al/N co-doped carbon nanoparticles via a hydrothermal method. • The Al/N co-doped carbon dots possessed higher luminescence than the primordial one. • The cause for the enhanced photoluminescence was investigated and discussed

[en] A novel dual-emitting Ca₈ZrMg(PO₄)₆(SiO₄): (Eu³⁺, Eu²⁺) phosphors with ultrahigh-sensitive optical temperature sensing are prepared by a conventional solid-state method. The Eu²⁺/Eu³⁺ co-activated Ca₈ZrMg(PO₄)₆(SiO₄) phosphors exhibit efficient dual-mode emissions with an intense, broad blue emission peaked at 414 nm and a relative bright red-emitting centered at 614 nm under 297 nm UV-light excitation, respectively. Furthermore, the fluorescence intensity ratio (FIR) technology is applied to analyse the optical temperature sensing performance of Ca₈ZrMg(PO₄)₆(SiO₄): (Eu³⁺, Eu²⁺) phosphors. Based on different thermal quenching behavior of Eu²⁺ and Eu³⁺ dual-emitting centers, linear temperature-dependent FIR between Eu²⁺ and Eu³⁺ is obtained. The maximal absolute sensitivity reaches as high as 5.94% K⁻¹, which is superior to that for the other luminescent temperature sensing materials reported previously. Analyses of the temperature-dependent photoluminescence spectra and configurational coordinate diagrams for Ca₈ZrMg(PO₄)₆(SiO₄): (Eu³⁺, Eu²⁺) phosphors indicate that the temperature-sensitive variation in FIR of Eu²⁺ to Eu³⁺ is originated from the difference in thermal quenching activation energy for 5d→4f transition of Eu²⁺ and ⁵D₀→⁷F_J (J = 1, 2, 4) transitions of Eu³⁺. These results reveal that the Ca₈ZrMg(PO₄)₆(SiO₄): (Eu³⁺, Eu²⁺) phosphors show glorious potential in high temperature optical thermometry.

[en] A series of Ca₉Zn_1.5(PO₄)₇: Eu, Tb phosphors were prepared by solid-state reaction method under reductive atmosphere. The crystal structure and morphology of the phosphors were characterized by the X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the phosphors were pure and the doped ions did not change the structure of phosphors. Photoluminescence results indicated that Ca₉Zn_1.5(PO₄)₇: Eu shows a sharp blue emission peaking at 420 nm that was produced by 4f-5d transition of Eu²⁺, and accompanied by the emission of Eu³⁺ under UV excitation. The phosphor of Ca₉Zn_1.5(PO₄)₇: Tb shows that peaks within 370–380 nm correspond to the ⁷F₆→⁵D₃, ⁵G₆, and ⁵L₁₀ transitions. Additionally, the corresponding CIE color coordinate of Ca₉Zn_1.5(PO₄)₇: Eu, Tb changes from (0.2548, 0.087) to (0.3365, 0.3117) due to the energy transfer of Eu²⁺→Tb³⁺→Eu³⁺, which covering the purple to white region. Based on these summary, Ca₉Zn_1.5(PO₄)₇: Eu, Tb is a potential single-host white light emitting phosphor applied in WLEDs.

[en] Eu²⁺/Eu³⁺ co-doped Ca₉Mg_1.5(PO₄)₇ phosphors are prepared through a convenient solid phase reaction, and their optical characteristics were studied to investigate the possible applications in luminescence thermometric field. The conformation of Eu²⁺ and Eu³⁺ dual-emitting centers in Ca₉Mg_1.5(PO₄)₇ host was veritied by X-ray photoelectron spectroscopy, photoluminescence spectra and decay curves. In Eu²⁺/Eu³⁺ co-activated Ca₉Mg_1.5(PO₄)₇ thermometric phosphor, not only the Eu²⁺-blue emission and Eu³⁺-red emission, but also the double-sites emissions in blue and red regions of Eu²⁺ ions can be used as FIR signals. Moreover, the exhaustive mechanism is discussed in depth with the measured data, and the intense temperature dependence is interpreted in the light of thermal-quenching. Additionally, benefited from their diverse thermal quenching behavior, the fluorescence intensity ratio (FIR) of Eu³⁺ to Eu²⁺ displays remarkable linear temperature-dependent and the maximum sensitivity is 8.40 × 10⁻⁵ K⁻¹ for the obtained phosphors. Moreover, the FIR of Eu²⁺ (I₆₀₀) to Eu²⁺ (I₄₁₅) is fitted very well, and the maximum value of S_r is 1.192% K⁻¹ at 383 K, as well as the value of S_a is 0.064 K⁻¹. As a consequence, this work indicates that Ca₉Mg_1.5(PO₄)₇: Eu²⁺/Eu³⁺ phosphors could be widely applied in optical temperature sensors.

[en] A series of emission-tunable TbZn_1−x(B₅O₁₀):xMn²⁺ phosphor were prepared by the conventional high temperature solid-state method. The lattice structure, and particularly the luminescence properties upon ultraviolet light excitation were studied. It is revealed that Mn²⁺ ions only occupy Zn²⁺ sites. And the characteristic ⁵D₄-⁷F_J emissions of Tb³⁺ were also studied in TbZn_1−x(B₅O₁₀):xMn²⁺ under the excitation of 365 nm. By doping Mn²⁺ in the TbZn(B₅O₁₀) host, red light at 625 nm was observed due to the transition of ⁴T_1g(G)→⁶A_1g(S). The energy transfer mechanism between Tb³⁺ and Mn²⁺ was verified by the fluorescence spectra and decay curves. And the energy transfer efficiencies were discussed. Moreover, color-tunable range from green to red can be realized in TbZn_1−x(B₅O₁₀):xMn²⁺(0 x 2+ ions. The above investigations indicate that TbZn_1−x(B₅O₁₀):xMn²⁺ have great potential in luminescent devices.

[en] Highlights: • 3D Cu_xO–Cu composite was prepared by a chemical corrosion method. • Cu_xO–Cu electrode exhibited an enhanced pseudo-capacitive performance. • Cu_xO–Cu//AC asymmetric supercapacitor can deliver a high energy density of 34.36 μW cm⁻² at a power density of 400 μW cm⁻². 3D Cu_xO–Cu nanostructures were synthesized through a simple chemical corrosion method and were employed as binder-free electrodes for supercapacitors. Owing to the direct growth of the active materials onto the Cu foam without any binders, and the 3D interconnected structure ensures a highly conductive network favorable for electron transfer, the as-prepared electrode exhibit a high specific capacitance of 111 mF cm⁻² at 0.5 mA cm⁻² and a better rate capability of 80 mF cm⁻² at 10 mA cm⁻². Besides, the Cu_xO–Cu//AC asymmetric supercapacitor can deliver a high energy density of 34.36 μW h cm⁻², thus showing great potential for supercapacitor applications.

[en] Fluorophosphate glasses doped with different Tm"3"+ concentrations were prepared. Thermal stability, absorption and fluorescence spectra were measured. J–O parameters and radiative properties were analyzed in detail. The prepared glass possesses high effective emission bandwidth (230 nm), large emission cross section (5.5×10"−"2"1 cm"2) and gain coefficient (0.97 cm"−"1). The optimal 1.8 μm emission can be obtained when Tm"3"+ concentration is fixed to 6 mol%. Results indicate that the prepared FP glass is an attractive candidate for potential 2 μm applications. - Highlights: • Fluorophosphate glasses with various Tm"3"+ concentrations were prepared. • The optimal 1.8 μm emission was obtained with Tm"3"+ concentration of 6 mol%. • Emission bandwidth, emission cross section, lifetime and gain spectra were obtained