Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approa...Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.展开更多
Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)...Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)LuNbO_(6):Eu^(3+)phosphor with double-perovskite structure was successfully prepared.Here,a series of Ba_(2)LuNbO_(6):Eu^(3+)red phosphors can be efficiently pumped by the near-ultraviolet(UV)light and then present high-brightness at orange emission(598 nm,~5D_(0)→~7 F_(1))and red emission(610 nm,~5D_(0)→~7 F_(2)).The ratio values of 610 to 598 nm in Ba_(2)LuNbO_(6):Eu^(3+)phosphors exceed 1 when the content of Eu^(3+)is larger than 0.4 mol,because the occupation of Eu^(3+)ions is changed from Lu^(3+)ions with symmetric sites to Ba^(2+)ions with asymmetric sites.Besides,the optimized concentration of Eu^(3+)at the~5D_(0)→~7 F_(2)transitions is obtained when x=1,indicating that there is non-concentration quenching in Ba_(2)LuNbO_(6):Eu^(3+)phosphors.Moreover,the CIE chromaticity coordinates of Ba_(2)LuNbO_(6):Eu^(3+)was calculated to be(0.587,0.361),the color purity was calculated to be 72.26%and internal quenching efficiency(IQE)was measured to be 67%.Finally,the thermal stability of Ba_(2)LuNbO_(6):Eu^(3+)phosphors was also studied.Our work demonstrates that the novel double-perovskite red-emitting Ba_(2)LuNbO_(6):Eu^(3+)phosphors are prospective red emitting elements for WLEDs applications.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.61965012)Project of Yunnan Provincial Natural Science Foundation(Nos.202001AS070008,202101AT070126)+3 种基金Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(No.YNWRQNBJ-2018-295)the Excellent Youth Project of Yunnan Province Applied Basic Research Project(No.2019FI001)Rare and Precious Metal Materials Genome Engineering Project of Yunnan Province(No.202002AB080001)Sichuan Natural Science Foundation(No.2022JDJQ0030).
文摘Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.
基金Project supported by the Excellent Youth Project of Yunnan Province Applied Basic Research Project(2019FI001)the National Natural Science Foundation of China(61775187,61965012,12064022)the Key Project of Yunnan Provincial Natural Science Foundation(202101AT070126)。
文摘Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)LuNbO_(6):Eu^(3+)phosphor with double-perovskite structure was successfully prepared.Here,a series of Ba_(2)LuNbO_(6):Eu^(3+)red phosphors can be efficiently pumped by the near-ultraviolet(UV)light and then present high-brightness at orange emission(598 nm,~5D_(0)→~7 F_(1))and red emission(610 nm,~5D_(0)→~7 F_(2)).The ratio values of 610 to 598 nm in Ba_(2)LuNbO_(6):Eu^(3+)phosphors exceed 1 when the content of Eu^(3+)is larger than 0.4 mol,because the occupation of Eu^(3+)ions is changed from Lu^(3+)ions with symmetric sites to Ba^(2+)ions with asymmetric sites.Besides,the optimized concentration of Eu^(3+)at the~5D_(0)→~7 F_(2)transitions is obtained when x=1,indicating that there is non-concentration quenching in Ba_(2)LuNbO_(6):Eu^(3+)phosphors.Moreover,the CIE chromaticity coordinates of Ba_(2)LuNbO_(6):Eu^(3+)was calculated to be(0.587,0.361),the color purity was calculated to be 72.26%and internal quenching efficiency(IQE)was measured to be 67%.Finally,the thermal stability of Ba_(2)LuNbO_(6):Eu^(3+)phosphors was also studied.Our work demonstrates that the novel double-perovskite red-emitting Ba_(2)LuNbO_(6):Eu^(3+)phosphors are prospective red emitting elements for WLEDs applications.
