Microwave-assisted fast synthesis and red-emitting properties of a borotellurate-based phosphor with excellent thermostability

At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a microwave-assisted fast synthesis approach to obtain a Sm^(3+)-activated borotellurate Na_(2)Y_(2)TeO_(4)(BO_(3))_(2)(NYTB)red phosphor with high crystallinity,excellent thermostability,and low chromaticity shift.For the NYTB-based phosphor,in contrast to the conventional solid-state synthesis,the microwave-assisted synthesis method involves lower synthesis temperature and shorter processing time.Additionally,the concentration quenching mechanism was determined.The w-LED device packaged with the studied phosphor exhibits a near-standard white light with proper CCT and high Ra parameters.

Thermometric properties of Na_(2)Y_(2)TeB_(2)O_(10):Tb^(3+)green phosphor based on fluorescence/excitation intensity ratio

For noncontact optical thermometry,in contrast with fluorescence intensity ratio(FIR)technology,excitation intensity ratio(EIR)technology has been seriously limited due to low sensitivity.Moreover,by exploring all possible temperature-dependent response,developing multimode optical thermometry is of great importance.In this work,a new Na_(2)Y_(2)TeB_(2)O_(10):Tb^(3+)phosphor is obtained by a solid-state reaction.Based on FIR and EIR models of Tb',thermometric properties are studied thoroughly.Excellent relative and absolute sensitivity(S_(R)and S_(A))are acquired due to the significant difference in emission/excitation lines in response to temperature.Meanwhile,Tb^(3+)content-dependent luminescence quenching mechanism is discussed.This study shows a feasible route for exploiting well-performing FIR-/EIR-based thermometric materials.

NUV-pumped luminescence of thermally stable samarium-activated alkali metal borophosphate phosphor

Exploring outstanding rare-earth activated inorganic phosphors with good thermostability has always been a research focus for high-power white light-emitting diodes(LEDs).In this study,we report a Sm^(3+)-activated KNa_(4)B_(2)P_(3)O_(13)(KNBP)powder phase.Its particle morphology,photoluminescence properties,concentration quenching mechanism,thermal quenching mechanism,and chromatic properties are demonstrated.Upon the near-ultraviolet(NUV)irradiation of 402 nm,the powder phase exhibits orange-red visible luminescence performance,originating from typical ^(4)G_(5/2)→^(6)H_(J/2)(J=5,7,9)transitions of Sm^(3+).Importantly,the photoluminescence performance has good thermostability,low correlated color temperature(CCT),and high color purity(CP),indicating its promising application in the NUV-pumped warm white LEDs.