A review on fluorescence intensity ratio thermometer based on rare-earth and transition metal ions doped inorganic luminescent materials

The host–guest composite, RhB@Tb-dcpcpt, is synthesized by trapping rhodamine B (RhB) into the channels of [Me2NH2][Tb3(dcpcpt)3(HCOO)]·DMF·15H2O (Tb-dcpcpt, DMF = N,N'-dimethylformamide) via an io...

Highly Water-Stable Dye@Ln-MOFs for Sensitive and Selective Detection toward Antibiotics in Water

Recently, controllable luminescence tuning and single-phased white light emission have been extensively studied to improve the luminescence performances of phosphors for white light-emitting diodes (WLEDs). In this work, the controllable photoluminescence tuning from bluish-green to red was successfully achieved in Bi3+,Eu3+-codoped Sr2−yBayLaGaO5 solid solutions, combining the effects of crystallographic site engineering and energy transfer. The phase composition and structural variation of the designed phosphors were thoroughly analyzed through X-ray powder diffraction (XRD) and Rietveld refinement. The effects of cation substitutions on the photoluminescence properties were investigated in detail and the corresponding mechanism was proposed. A regular red-shift of Sr2−yBayLaGaO5:0.02Bi3+ in the bluish-green region could be observed when Sr2+ was substituted by Ba2+, which is attributed to the crystal field splitting and nephelauxetic effect. The red-shift of emission of Ba2LaGaO5:0.02Bi3+ phosphor with gradually increasing excitation wavelength reveals that Bi3+ ions occupy different cation sites to form multiple luminescent centers. Besides, the efficient energy transfer was designed and successfully realized in Sr2−yBayLaGaO5:0.02Bi3+,zEu3+ (y = 0–2.0; z = 0–0.20) samples. The energy transfer efficiency can reach up to 88%, 91% and 77% at z = 0.20 for y = 0, 1.0 and 2.0, respectively. Moreover, the thermal quenching behaviors of the studied phosphors reveal that the codoping of Eu3+ could efficiently improve the thermal stability of Sr2LaGaO5:0.02Bi3+ phosphor. Finally, the WLED devices were fabricated by composing 370 nm UV chips and single-phased Sr2−yBayLaGaO5:0.02Bi3+,0.05Eu3+ (y = 0, 1.0, 2.0) phosphors. The as-fabricated devices presented relatively excellent EL performances, the color coordinates of which all locate in the warm white light region. These results indicate the as-prepared Sr2−yBayLaGaO5:Bi3+,Eu3+ phosphors can be potential candidates for color tuning and efficient single-phased white emission in UV-based WLED lighting applications.

Luminescence color tuning and energy transfer properties in (Sr,Ba)2LaGaO5:Bi3+,Eu3+ solid solution phosphors: realization of single-phased white emission for WLEDs

Ratiometric optical thermometer based on thermally coupled levels and non-thermally coupled levels

A review and outlook of ratiometric optical thermometer based on thermally coupled levels and non-thermally coupled levels

Pr3+ doped BaNb2O6 reddish orange emitting phosphor for solid state lighting and optical thermometry applications

In the present context, detailed spectroscopic analysis of Cr3+ doped ZnGa2O4 has been reported. Hydrothermal method was adopted for the formation of nanoparticles. XRD patterns revealed the cubic phase with good crystallinity. The PL emission spectra showed a broadband NIR emission with a sharp peak from the 4T2 and 2E states of Cr3+. Strong crystal field strength was estimated from the spectroscopic data for the Cr3+ ion in ZnGa2O4 host. The material also showed long afterglow property. With increase of temperature, the FWHMs of the emission band were found to be increased and the average lifetimes were decreased because of the increasing population of the 4T2 state. Further, the system was utilized for optical temperature sensing using lifetime based technique and maximum sensitivity was obtained as 0.018 K-1. UV, as well as blue and orange light was found to be suitable to be used as excitation sources for temperature sensing measurement. The possibility of the present nanophosphor to emit a long persistent signal in first biological window and the significant temperature dependent photoluminescence property allows it to be considered as a promising material in bioimaging application as well as for temperature sensing in biotechnological applications.

Investigation on spectroscopic properties and temperature dependent photoluminescence of NIR emitting Cr3+ doped zinc gallate long persistent nanophosphor

A single phase white light emitting Dy3+ doped LiCaBO3 phosphors were prepared by solid-state reaction method at 700 °C. The crystal structure properties were analyzed by utilizing powder X-ray Diffraction and followed by the profile fitting to calculate the lattice parameters. The FESEM, UV–Vis, photoluminescence excitation and emission spectra, decay time and quantum yield measurement were utilized to characterize the samples. The temperature dependent photoluminescence emission and decay times were recorded in the temperature range 100–480 K. The phosphor exhibits two emission bands at 485 nm (blue) and 578 nm (yellow) originating from the f–f transition of Dy3+. The optimized doping concentration for maximum emission intensity was 2 mol%. A near white emission was achieved with color co-ordinate (0.35, 0.39) and CCT value 4955 K. The material had excellent thermal and color stability. The absolute quantum yield is 0.25. So the near white emission, excellent thermal stability and suitable quantum yield of LiCaBO3: Dy3+ can be a promising candidate for near UV–LED pumped white light emitting diode.

Temperature dependent photoluminescence of Dy3+ doped LiCaBO3 phosphor

A multicolor BaAl2O4:Eu2+,Dy3+/dye encapsulated in mesoporous SiO2 composite long persistent phosphor is developed based on a radiative energy transfer process Multicolor long persistence luminescence is achieved through radiative energy transfer from BaAl2O4:Eu2+,Dy3+ to rhodamine 6G or rhodamine B dye encapsulated in mesoporous silica nanoparticles BaAl2O4:Eu2+,Dy3+ (BAO) is a cyan-emitting long persistent phosphor with high brightness and a long afterglow time For color tuning, rhodamine 6G dye encapsulated in mesoporous silica (MSNP-Rh6G) or rhodamine B dye encapsulated in mesoporous silica (MSNP-RhB) nanoparticles are mixed with BAO phosphor in different weight ratios to afford BAO/MSNP-Rh6G and BAO/MSNP-RhB composite phosphors BAO/MSNP-Rh6G shows a long persistent emission with colors varying from cyan to yellow, with similar color tuning observed for BAO/MSNP-RhB A possible afterglow mechanism is described The multicolor long persistent phosphors are potentially applicable in displays, bio-imaging, and luminous paints

Composites of BaAl2O4:Eu2+,Dy3+/organic dye encapsulated in mesoporous silica as multicolor long persistent phosphors based on radiative energy transfer

Sourav Das

Papers

Pr3+ doped BaNb2O6 reddish orange emitting phosphor for solid state lighting and optical thermometry applications

Investigation on spectroscopic properties and temperature dependent photoluminescence of NIR emitting Cr3+ doped zinc gallate long persistent nanophosphor

Temperature dependent photoluminescence of Dy3+ doped LiCaBO3 phosphor

Composites of BaAl2O4:Eu2+,Dy3+/organic dye encapsulated in mesoporous silica as multicolor long persistent phosphors based on radiative energy transfer

Near infrared emitting Cr3+ doped Zn3Ga2Ge2O10 long persistent phosphor for night vision surveillance and anti-counterfeit applications