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In this work, we studied the optical properties of Dy-doped Gd2O3 nanoparticles (NPs) before and after their APTES functionalisation. We obtained luminescent Dy@Gd2O3 NPs (0.5, 1, and 5% mol) using a modified polyol method. Our work describes their detailed structural analysis using FT-IR, XRD, HRTEM, TGA and XAS techniques. The results show that these systems present a crystalline structure with a body-centred cubic cell and particle sizes of 10 nm. The dopant position was inferred as substitutional, through XAS analysis at the M4,5-edges of Gd and Dy and K-edge of O, and in C2 sites, based on photoluminescence studies. There was sensitization of the luminescence by the matrix as shown by the emission increase of the hypersensitive transition (6F9/2 → 6H13/2, 572 nm) and also a broadband appears around 510 nm attributed to defects in Gd2O3. An enhanced emissive lifetime of 398 μs was found for the sample doped at 1%. We functionalised the Dy@Gd2O3 (at 1%) NPs with 3-aminopropiltrietoxisilane (APTES) for further application as a biomarker sensor. We found that these NPs conserved their luminescence after adding the surface agent (avoiding quenching effects) making them potential materials for biosensing. [ABSTRACT FROM AUTHOR]

A new blue light-emitting molecular–organic framework namely FQUNAM-MOF (1) was synthesized in a simple way using formic acid and zinc nitrate as precursors. In the present work, the potential of 1 as an efficient antenna for terbium and europium 3+ ions was evaluated at different dopant ratios. The compounds labelled Eu3+0.3−nTb3+n@1 where n = 0.15, 0.18, and 0.21, are isostructural and their luminescence properties were studied in detail. Excellent energy transfer occurs from the MOF-excited energy levels towards the 5D4 state in Tb3+, unlike Eu3+ where the sensibilization predominantly arises from the 5D4 terbium state. These compounds exhibit a high solid-state quantum yield (QY) from 23.4 to 48.5%, higher than the reported values, and they show thermal stability at high temperatures. Additionally, a white light-emitting device (WLED) was prepared using a resin in which 20% (w/w) of the Eu0.09Tb0.21@1 compound (48.5% QY) was added. It displayed a white-cold light emission colour according to the Commission Internationale de I'Éclairage (CIE) classification (applying current values of 10, 30, and 100 mA). These materials contribute to the emerging field of molecular–organic frameworks for the development of new efficient and stable lighting sources. [ABSTRACT FROM AUTHOR]

In this work, we studied the optical properties of Dy-doped Gd 2 O 3 nanoparticles (NPs) before and after their APTES functionalisation. We obtained luminescent Dy@Gd 2 O 3 NPs (0.5, 1, and 5% mol) using a modified polyol method. Our work describes their detailed structural analysis using FT-IR, XRD, HRTEM, TGA and XAS techniques. The results show that these systems present a crystalline structure with a body-centred cubic cell and particle sizes of 10 nm. The dopant position was inferred as substitutional, through XAS analysis at the M 4,5 -edges of Gd and Dy and K-edge of O, and in C 2 sites, based on photoluminescence studies. There was sensitization of the luminescence by the matrix as shown by the emission increase of the hypersensitive transition ( 6 F 9/2 → 6 H 13/2 , 572 nm) and also a broadband appears around 510 nm attributed to defects in Gd 2 O 3 . An enhanced emissive lifetime of 398 μs was found for the sample doped at 1%. We functionalised the Dy@Gd 2 O 3 (at 1%) NPs with 3-aminopropiltrietoxisilane (APTES) for further application as a biomarker sensor. We found that these NPs conserved their luminescence after adding the surface agent (avoiding quenching effects) making them potential materials for biosensing.

A series of Tb 3+ /Eu 3+ -codoped phosphor ceramic plates with a high color rendering index (CRI) for a near-ultraviolet light emitting diode (LED) were fabricated. Color emission can be tuned from green to reddish as a function of Eu 3+ concentration. By doping only 0.15 mol% of Eu 3+ concentration, a comfortable warm white emission is promoted as a result of simultaneous emissions of Tb 3+ and Eu 3+ ions. A theoretical model is proposed to calculate the contributions of the emitted color of the donor (Tb 3+ ) and acceptor (Eu 3+ ) ions in terms of europium concentration. The energy transfer from Tb 3+ to Eu 3+ ions is corroborated by the luminescence spectra and decay time of Tb 3+ , with a maximum energy transfer efficiency of 76% for 28 mol% of Tb 3+ and 14 mol% of Eu 3+ . Warm white LEDs were constructed using a 380 nm UV chip and showed a CRI of 82.5, which was one of highest values reported for Tb 3+ /Eu 3+ -codoped samples. Color-correlated temperature (CCT), color coordinate (CC), and luminous efficacy (LE) were utilized to know the potentials as a phosphor converter in solid-state lighting.