Tailoring The Luminescence Properties Of Eu Based Rare Earth Phosphors

The rare-earth derive phosphors have attracted much attention in biomedicine,illumination and optical display fields for their unique merits:strong and sharp line-like emission,and high luminous efficiency.Many approaches have been proposed for tailoring color emission of lamp phosphors by tuning the contents of REEs,such as Ce³⁺,Tb³⁺,Eu³⁺.As we know,the separation and purifying of REEs from waste phosphors usually requires high cost and complicated operations.Thus,it is important to investigate how to make full use of rare earth.Here we report the phosphor only based on Eu doped in different matrices with manipulated color,which will minimize the environmental challenges present in the transition to a green economy.The prepared samples were characterized by morphology,optical properties,and temperature-sensitive properties.The main results of this paper are list as follows:1.Tailoring emission of SrAl₂O₄:Eu²⁺and Eu?TTA?₃phen rare earth phosphorsThe SAOE particles with strong green?510 nm?emission were prepared via a solid-state reaction.Eu shows enhanced red?612 nm?luminescence upon bonding with TTA and phen which served as organic ligands to chelate RE ions and transfer exciting light to the RE ions efficiently.The prepared materials exhibit well photostability under continuously direct exposure to 365 nm UV light?irradiation intensity 0.15 mW/cm²?for 10 hours.By adjusting the mass ratios of SAOE and TTAE?1:0,1:25,1:50,1:100,1:200,1:300,1:400,0:1?,the emission colors of the hybrid materials can be tuned from red to green.The chromaticity coordinates were also calculated,which fell well in the red,orange,yellow and green regions of 1931 CIE chromaticity diagram,the resultant samples were denoted as P?A-H?.According to the spectroscopic studies,the absorption almost has no overlap on the emissions of SAOE and TTAE powders,leading to efficient PL emitting with high photoluminescence quantum yields of 24%-68%.Besides,through deposition of the hybrid materials with polydimethylsiloxane?PDMS?onto the 365 nm UV-LED chip,tunable color light-emitting diodes were fabricated,they show excellent luminescence properties,indicating their potential application in optical device and offering a novel approach for designing multi-color phosphor materials.2.Thermosensors based on SrAl₂O₄:Eu²⁺and Eu?TTA?₃phen rare earth hybrid materialsThe temperature sensing characteristics of the synthesized hybrid materials?mass ratio 1:25?were studied.The samples were temperature-sensitive tested by a laboratory self-assembly temperature test system.It was found that the luminescence intensity of TTAE hybrid luminescent material in the sample shows a strong dependence on temperature in the range from 20 to 200°C,while the luminescence intensity of the SAOE is almost not be altered.The green light emission of 510 nm is used as the internal reference,and the red light emission of 612 nm is used as the detection signal.The increased temperature can lead to variations of the two fluorescence intensity ratios of 612 nm and 510 nm.The color of the sample transitions from bright orange red to green under the ultraviolet lamp when the temperature is changed.Hence,we can realize the visual observation of temperature changes.