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A new polyoxometalate-based inorganic-organic hybrid compound (ClBzQl)3[PMo12O40] 1 (ClBzQl = 1-(4′-Cl-benzyl)quinoli- nium cation) has been synthesized by hydrothermal method and characterized by IR, elemental analysis, and X-ray crystallography. Analysis of the crystal structure of 1 suggests that there are multiform intermolecular C−H···O hydrogen bonds between polyoxoanions and organic cations and obvious face-to-face π−π interactions involving quinoline rings of adjacent cations. The luminescent properties of the compound 1 in the solid state at room temperature were investigated. [ABSTRACT FROM PUBLISHER]

Lanthanide-doped upconversion photoluminescent nanoparticles with unique anti-Stokes spectroscopic properties excel in many fields of application. Ytterbium-based self-sensitized fluorides with rich Yb3+ possess higher absorption efficiency of incident near infrared laser, and are more favorable for photoluminescence or optical heating applications. In this work, α-NaYbF 4 :Tm3+ crystalline nanoparticles are synthesized, which exhibit intense ultraviolet self-sensitized upconversion photoluminescence and highly efficient optical heating capability under 980 nm laser excitation. NaYbF 4 :Tm3+ nanocrystals emit multi-band luminescence with emission peaks located in the ultraviolet, blue and red spectral regions. The energy transfer mechanism and electronic transition pathways for the Upconversion luminescence are investigated based on the energy level scheme, and are further confirmed by luminescent dynamic analysis. Due to cross-relaxations between Tm3+ and energy back transfer from Tm3+ to Yb3+ processes, the NaYbF 4 : 1 mol% Tm3+ nanoparticles possess the highest luminescence intensity. The luminescent dynamic characteristics, such as decay time and rise time, vary with Tm3+ doping concentrations. Highly efficient optical heating effect is observed in the NaYbF 4 :Tm3+ nanoparticles with slope efficiency of photothermal conversion for 10 s laser irradiation is as high as 100.48 °C/W. [ABSTRACT FROM AUTHOR]

Aggregation-caused quenching (ACQ) effect, known as the main cause to restrain solid-state luminescence of carbon quantum dots (CQDs), hinders further application of CQDs in white light-emitting diodes (WLED). Here, a complex of CQDs and phthalimide crystals (CQDs/PC) was prepared through a one-step solvothermal method. CQDs/PC prevented CQDs from touching directly by embedding the CQDs in phthalimide crystal matrix in situ, which effectively reduced the ACQ effect. Furthermore, CQDs/PC exhibited multi-peak fluorescence spectra that span the green, yellow and orange spectral regions. Finally, a WLED fabricated based on CQDs/PC achieved a color-rendering index of 82 and a correlated color temperature of 5430 K. This work provides a quick and effective strategy to apply CQDs to WLED. [ABSTRACT FROM AUTHOR]

Highly luminescent nitrogen-doped carbon dots (N-CDs) were synthesized rapidly by one-step microwave-assisted hydrothermal method using citric acid as carbon source and ethylenediamine as dopant. The influences of reaction temperature, reaction time and raw material ratio on the fluorescence performance of N-CDs were investigated. Then N-CDs with the highest quantum yield were selected as fluorescent materials for fabricating white light-emitting diodes (LEDs). Highly luminescent N-CDs with the quantum yield of 75.96% and blue-to-red spectral composition of 51.48% were obtained at the conditions of 180 °C, 8 min and the molar ratio of citric acid to ethylenediamine 2:1. As-prepared highly luminescent N-CDs have an average size of 6.06 nm, possess extensive oxygen- and nitrogen-containing functional groups on their surface, and exhibit strong absorption in ultraviolet region. White LEDs based on the highly luminescent N-CDs emit warm white light with color coordinates of (0.42, 0.40) and correlated color temperature of 3416 K. [ABSTRACT FROM AUTHOR]

A photoactive metal–organic framework with 1D Cu-I chain displays strong visible light adsorption, and photocatalytic degradation of methylene blue. [Display omitted] • A 3D metal–organic framework (MOF) featuring 1D Cu-I chain is constructed. • 1D Cu-I chains features Cu 3 I 2 cluster. • It displays good visible light adsorption and photocatalytic degradation of methylene blue. Presented here is a photoactive cluster-organic frameworks with 1D Cu-I chain, namely (Cu 2 I)(pytz) (1) (Hpytz = 5-(4′-pyridyl)tetrazole). Compound 1 features a unique 1D Cu-I chain constructed from a Cu 3 I 2 cluster. These chains are interconnected by the tetrazole moiety of pytz, forming a 2D layer. Furthermore, the pyridine moiety of pytz acts as pillars, creating a pillar-layered framework. Moreover, compound 1 displays strong photoluminescence, excellent visible light adsorption, and remarkable photocatalytic activity for the degradation of methylene blue under visible light conditions. These properties highlight the potential applications of these frameworks in areas such as optoelectronics and environmental remediation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two versatile 3D polymers have been synthesized with d10 metal ions. [•] IR, PXRD, TG technique for the polymers. [•] X-ray single-crystal structure analyses and discussion for the polymers. [•] The polymers exhibit interesting luminescence properties in solid state. [ABSTRACT FROM AUTHOR]

In recent years, upconversion photoluminescent micro/nanocrystals with unique anti-Stokes luminescence properties have shown high application value in many relevant fields. In this work, pure tetragonal phase NaLa(MoO 4) 2 :Yb3+/Ho3+ microspheres have been synthesized by a solvothermal method in the presence of oleic acid and 1-octadecene. Under the excitation of 980 nm laser, NaLa(MoO 4) 2 :Yb3+/Ho3+ microcrystals emit red, green and near infrared upconversion luminescence with peak wavelengths at 660/643 nm, 541 nm, and 756 nm. Based on the analysis of excitation power-dependent upconversion luminescence intensities and energy level diagram of Yb3+/Ho3+, electronic transition pathways in the energy transfer processes for upconversion luminescence of NaLa(MoO 4) 2 :Yb3+/Ho3+ microcrystals are studied. For red upconversion luminescence at 660/643 nm, the predominant population pathway to state 5 F 5 (Ho3+) is "Yb3+ (2 F 5/2) + Ho3+ (5 I 7) → Yb3+ (2 F 7/2) + Ho3+ (5 F 5)". While, "Yb3+ (2 F 5/2) + Ho3+ (5 I 6) → Yb3+ (2 F 7/2) + Ho3+ (5 F 4 /5 S 2)" process accounts for the population of state 5 F 4 /5 S 2 (Ho3+) for radiative transitions of upconversion luminescence at 541 and 756 nm. Energy back transfer contributes to the intense red upconversion luminescence at 660/643 nm. These electronic transition pathways in energy transfer processes are further confirmed by the analyses based on energy level mismatch and luminescent lifetimes. [Display omitted] • Electronic transition pathways for energy transfer upconversion luminescence in NaLa(MoO 4) 2 :Yb3+/Ho3+ microcrystals. • Predominant population pathway for red upconversion luminescence at 660/643 nm of Ho3+ is elucidated. • Analyses of energy level mismatch and luminescent lifetimes confirm the proposed electronic transition pathways. [ABSTRACT FROM AUTHOR]