Y 1-a, Gd a) 3-x(Al 1-b, Ga b) 5O 12∶Ce 3+ x was synthesized by high-temperature solid state reaction in reducing atmosphere based on high purity raw materials. The influences of Y 3+, Gd 3+, Al 3...Y 1-a, Gd a) 3-x(Al 1-b, Ga b) 5O 12∶Ce 3+ x was synthesized by high-temperature solid state reaction in reducing atmosphere based on high purity raw materials. The influences of Y 3+, Gd 3+, Al 3+, Ga 3+ and activator-Ce 3+ on the performance of the phosphor were investigated. Ce 3+ is the luminescent center and activates the phosphor after it replaces Y partially. When x is less than 0.12, the volume of the crystal and the emission intensity of the phosphor increase with the quantity of Ce 3+. When CeO 2 is added too much, the phase CeAlO 3 will appear. The excitation and emission peaks of the phosphor will shift to longer wavelength when the amount of Gd 3+ increases. The wavelength of the emission peak can shift about 20 nm when a equals 0.45. In opposite, the excitation and emission peaks will shift to shorter wavelength, when part of Al 3+ is replaced by Ga 3+. The wavelength of the emission peak can shift about 20 nm when b equals 0.55. Through the replacemeat of Y 3+ or Al 3+ by Gd 3+ or Ga 3+, the emission peak of the phosphor can be adjusted from 520 to 560 nm. In this way, the phosphor is more suitable for different chips.展开更多
A broadband blue-emitting Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+)(x=0-0.2) phospho rs were synthesized,which can be used for near-UV pumped white light-emitting diodes(w-LEDs).The crystal structures,photoluminescence pro pe...A broadband blue-emitting Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+)(x=0-0.2) phospho rs were synthesized,which can be used for near-UV pumped white light-emitting diodes(w-LEDs).The crystal structures,photoluminescence pro perties,external quantum efficiency,the rmal stability and application perfo rmance of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+),by partially substituting Sr^(2+) with Ca^(2+)(x=0-0.2),were studied by various analytical techniques.When the Ca/Sr ratio of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) gradually increases,the emission peak of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) red-shiftes from 459 to 465 nm,corrected external quantum efficiency increases from 31.8% to 42.9%,and the thermal stability is also improved.The mechanism of the changes of the photoluminescence emission and excitation spectra,external quantum efficiency and thermal stability properties was also investigated in detail.In addition,a w-LED was fabricated by using SrLu_(2)O_(4):Ce^(3+)(blue),β-sialon:Eu^(2+)(green) and(Sr,Ca)AlSiN_(3):Eu^(2+)(red) phosphors combined with a 405 nm near-UV LED chip,and its color rendering index(CRI) reaches 96.0.When Sr_(0.8)Ca_(0.2)Lu_(2)O_(4):Ce^(3+) is applied as blue phosphor to substitute SrLu_(2)O_(4):Ce^(3+),the obtained w-LED devices have high luminous efficiency,and CRI greater than 95.0.These re sults show that the Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) can be potential blue phosphors for n-UV pumped high CRI w-LEDs application.展开更多
文摘Y 1-a, Gd a) 3-x(Al 1-b, Ga b) 5O 12∶Ce 3+ x was synthesized by high-temperature solid state reaction in reducing atmosphere based on high purity raw materials. The influences of Y 3+, Gd 3+, Al 3+, Ga 3+ and activator-Ce 3+ on the performance of the phosphor were investigated. Ce 3+ is the luminescent center and activates the phosphor after it replaces Y partially. When x is less than 0.12, the volume of the crystal and the emission intensity of the phosphor increase with the quantity of Ce 3+. When CeO 2 is added too much, the phase CeAlO 3 will appear. The excitation and emission peaks of the phosphor will shift to longer wavelength when the amount of Gd 3+ increases. The wavelength of the emission peak can shift about 20 nm when a equals 0.45. In opposite, the excitation and emission peaks will shift to shorter wavelength, when part of Al 3+ is replaced by Ga 3+. The wavelength of the emission peak can shift about 20 nm when b equals 0.55. Through the replacemeat of Y 3+ or Al 3+ by Gd 3+ or Ga 3+, the emission peak of the phosphor can be adjusted from 520 to 560 nm. In this way, the phosphor is more suitable for different chips.
基金Project supported by the National Key Research and Development Program of China(2017YFB0404301)。
文摘A broadband blue-emitting Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+)(x=0-0.2) phospho rs were synthesized,which can be used for near-UV pumped white light-emitting diodes(w-LEDs).The crystal structures,photoluminescence pro perties,external quantum efficiency,the rmal stability and application perfo rmance of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+),by partially substituting Sr^(2+) with Ca^(2+)(x=0-0.2),were studied by various analytical techniques.When the Ca/Sr ratio of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) gradually increases,the emission peak of Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) red-shiftes from 459 to 465 nm,corrected external quantum efficiency increases from 31.8% to 42.9%,and the thermal stability is also improved.The mechanism of the changes of the photoluminescence emission and excitation spectra,external quantum efficiency and thermal stability properties was also investigated in detail.In addition,a w-LED was fabricated by using SrLu_(2)O_(4):Ce^(3+)(blue),β-sialon:Eu^(2+)(green) and(Sr,Ca)AlSiN_(3):Eu^(2+)(red) phosphors combined with a 405 nm near-UV LED chip,and its color rendering index(CRI) reaches 96.0.When Sr_(0.8)Ca_(0.2)Lu_(2)O_(4):Ce^(3+) is applied as blue phosphor to substitute SrLu_(2)O_(4):Ce^(3+),the obtained w-LED devices have high luminous efficiency,and CRI greater than 95.0.These re sults show that the Sr_(1-x)Ca_(x)Lu_(2)O_(4):Ce^(3+) can be potential blue phosphors for n-UV pumped high CRI w-LEDs application.
