An energy transfer strategy for highly luminescent green-emitting Ce3+/Tb3+ codoped Ca2LaHf2Al3O12 garnet phosphors in white light-emitting diodes. (June 2022)

• Record Type: Journal Article
• Authors: Ma, Nan; Li, Wei; Devakumar, Balaji; Huang, Xiaoyong; Lee, Adam F.
• Is Part Of: Materials today chemistry. Volume 24(2022)
• Publication Date: 2022-06
• Subjects: Luminescence properties -- Garnet structure -- Quantum efficiency -- Ce3+ ions -- Solid-state lighting; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.100773
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: Bright, energy-efficient, and stable white lighting sources, such as light-emitting diodes, are desirable to mitigate climate change. A near-ultraviolet-excitable, green-emitting Ca2 LaHf2 Al3 O12 :Ce 3+, Tb 3+ garnet phosphor with high photoluminescence efficiency, prepared by solid-state synthesis, is described. X-ray diffraction Rietveld refinement reveals its garnet structure with space group Ia 3 ¯ d and crystallographic parameters a = b = c = 12.528 Å, α = β = γ = 90°, and V = 1966.470 Å 3 . On 408 nm excitation, it produces bright green light peaking at 543 nm owing to the 5 D4 → 7 F5 transition of Tb 3+ ions and demonstrates an ultrahigh internal quantum efficiency (80%) and high external quantum efficiency (59.2%). The luminescence intensity of Ca2 LaHf2 Al3 O12 :0.05Ce 3+, 0.6Tb 3+ is double that of a Ca2 LaHf2 Al3 O12 :0.05Ce 3+ green phosphor owing to Ce 3+ →Tb 3+ energy transfer. This Ca2 LaHf2 Al3 O12 :0.05Ce 3+, 0.6Tb 3+ green phosphor was used to fabricate a near-UV-pumped white LED device; the resulting luminous efficacy and color rendering index at 3397 K were 17.56 lm/W and 93.1, respectively. Graphical abstract: An efficient green-emitting Ca2 LaHf2 Al3 O12 :Ce 3+, Tb 3+ garnet phosphor was developed using a Ce 3+ →Tb 3+ energy transfer strategy for high-color rendering white light-emitting diodes. Image 1 Highlights: A near-UV-excitable green-emitting Ca2 LaHf2 Al3 O12 :Ce 3+, Tb 3+ phosphor was reported. Bright green emission around 543 nm was generated under 408 nm excitation. Internal quantum efficiency and external quantum efficiency reached 80% and 59.2%, respectively. Energy transfer from Ce 3+ to Tb 3+ ions was studied. This green phosphor enabled to fabricate a warm white light-emitting diode with a high color rendering index of 93.1.