Glass-compatible and self-powered temperature alarm system by temperature-responsive organic manganese halides via backward energy transfer process

A pioneering glass-compatible transparent temperature alarm system self-powered by luminescent solar concentrators(LSCs) is reported.Single green-emitted organic manganese halides(OMHs) of PEA_(2)MnBr_(2)I_(2),which has a unique temperature-dependent backward energy transfer process from selftrapped state to^(4)T_(1)energy level of Mn,is used for triggering the temperature alarm.The LSC with redemitted CsPbI_(3)perovskite-polymer composite films on the glass substrate is used for power supply.The spectrally separated nature between the green-emitted OMHs for temperature alarm and red-emitted CsPbI3in LSC for power supply allows for probing the signal light of temperature-responsive OMHs without the interference of LSCs,making it possible to calibrate the temperature visually just by a self-powered brightness detection circuit with LED indicators.Taking advantage of LSC without hot spot effects plaguing the solar cells,as-prepared temperature alarm system can operate well on both sunny and cloudy day.

Luminescence Characteristic of a New Novel Coprecipitate Rare Earth Complexes

The Tb 3+ ion was introduced in the Tb x Eu 1- x (BSA) 3phen as a bridge to make the energy transfer process from ligand to the Eu 3+ complex more efficient. The characteristics of the device used Tb x Eu 1- x (BSA) 3phen as the emission material with the different ratio of x were discussed. When x is 0.5, the device emits pure red color with the maximal brightness of 100 cd·m -2 and has good commutation property. The role of the Tb 3+ ion in the energy transfer process between the ligand and the Eu 3+ ion and the mechanism of energy transfer process were also discussed.

White emission from Tm^(3+)/Tb^(3+)/Eu^(3+) co-doped fluoride zirconate under ultraviolet excitation

We synthesize Tm3＋/Tb3＋/Eu3＋ triply-doped ZrF4-BaF2-LaF3-A1F3-NaF （ZBLAN） transparent glass by using a melt-quenching method. Under excitation of 365 nm, the white emission with Commission internationale deL＇Eclairage （CIE） coordinates of （0.33, 0.33） is achieved at the Eu3＋ concentration of 1.1 mol%. The mechanisms for white emission and the energy transfer process of Tb3＋→ Eu3＋ are discussed in terms of the photoluminescence, photoluminescence excitation spectra, and the light emission decay curves. The nature for the Tb3＋ → Eu3＋ energy transfer is described with the aid of an energy level diagram.

Luminescent characteristics of Tm^(3+)/Tb^(3+)/Eu^(3+) tri-doped Na_(5)Y_(9)F_(32) single crystals for white emission with high thermal stability

By using an improved Bridgman method,0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/y mol%Eu^(3+)(y=0,0.4,0.6,0.8)doped Na_(5)Y_(9)F_(32)single crystals were prepared.The x-ray diffraction,excitation spectra,emission spectra and fluorescence decay curves were used to explore the crystal structure and optical performance of the obtained samples.When excited by 362 nm light,the cool white emission was realized by Na_(5)Y_(9)F_(32)single crystal triply-doped with 0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/0.8 mol%Eu^(3+),in which the Commission Internationale de l’Eclairage(CIE)chromaticity coordinate was(0.2995,0.3298)and the correlated color temperature(CCT)was 6586 K.The integrated normalized emission intensity of the tridoped single crystal at 448 K could keep 62%of that at 298 K.The internal quantum yield(QY)was calculated to be~15.16%by integrating spheres.These results suggested that the single crystals tri-doped with Tm^(3+),Tb^(3+)and Eu^(3+)ions have a promising potential application for white light-emitting diodes(w-LEDs).

Structural and optical properties of Dy^(3+):YAlO3 phosphors for yellow light-emitting diode applications

The spectroscopic properties of a series of Dy^(3+)single-doped and Dy^(3+)/Nd^(3+),Dy^(3+)/Tb^(3+),and Dy^(3+)/Tm^(3+)co-doped YAlO_(3)(yttrium aluminum perovskite,YAP)phosphors were investigated and compared through the measurements of optical absorption,emission spectra,and fluorescence decay curves.For the Dy^(3+)ion single-doped samples,the intensity of each absorption band increases with an increment in Dy^(3+)ion doping concentration,and the identified strong absorption peak at 447 nm indicates that Dy^(3+):YAP phosphors are suitable to be pumped by a blue laser diode(LD).For all co-doped samples,absorption peaks of Dy^(3+)ion along with some of the absorption bands of Nd^(3+),Tb^(3+),and Tm^(3+)ions are observed.Under 351 and 447 nm excitation,a prominent emission peak at 572 nm was obtained in all the samples,corresponding to Dy^(3+):^(4)F_(9/2)→^(6)H_(13/2)transition.Here,2 at%Dy^(3+):YAP phosphor exhibits the highest yellow emission intensity under 447 nm pumping.Among the three kinds of Dy^(3+)co-doped phosphors,Dy^(3+)/Tb^(3+):YAP phosphor possesses the dominant yellow emission.The fluorescence decay curves show exponential behaviour and are fitted well.The Commission International de L’Eclairage(CIE)chromaticity coordinates were calculated following the respective emission spectra,and it is found that all the coordinates locate in the yellow region.The energy transfer(ET)processes were investigated and the concentration quenching mechanism was discussed.The obtained results suggest that Dy^(3+)-activated YAP phosphors are good candidates for yellow LED applications.

Photoluminescence properties and effect of Bi^(3+) dopant of Eu^(3+) and Dy^(3+) co-doped Sr_3V_2O_8

Photoluminescence properties of Sr 2.5 Dy 1/3-x Eu x V 2 O 8（x=0,0.06,0.12,0.18,0.24,0.33） were investigated.The excitation spectra included a broad band in the short wavelength region and several sharp lines in the longer wavelength region,and the spectral origin were discussed.The emission spectra were measured in two different exciting ways,i.e.,exciting the VO 4 group at 270 nm and the Eu 3＋ ion at 398 nm,respectively,and the energy transferring process was reasonably suggested.Furthermore,multi-color emission could be achieved in Sr 2.5 Dy 1/3-x Eu x V 2 O 8,indicating that the studied samples had potential applications in the white light emitting diodes.Further investigation showed that reducing the concentration of Eu 3＋ and Dy 3＋ and introducing Bi 3＋ as a sensitizer ion greatly enhanced the emission intensity.