Utilizing energy transfer strategy to produce efficient green luminescence in Ca2LuHf2Al3O12:Ce3+,Tb3+ garnet phosphors for high-quality near-UV-pumped warm-white LEDs

Nan Ma; Wei Li; Balaji Devakumar; Zongjie Zhang; Xiaoyong Huang

doi:10.1016/j.jcis.2021.05.108

Utilizing energy transfer strategy to produce efficient green luminescence in Ca₂LuHf₂Al₃O₁₂:Ce³⁺,Tb³⁺ garnet phosphors for high-quality near-UV-pumped warm-white LEDs

J Colloid Interface Sci. 2021 Nov:601:365-377. doi: 10.1016/j.jcis.2021.05.108. Epub 2021 May 23.

Authors

Nan Ma¹, Wei Li¹, Balaji Devakumar², Zongjie Zhang¹, Xiaoyong Huang³

Affiliations

¹ College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, PR China.
² Department of Physics, Sri Vidya Mandir Arts and Science College, Katteri, Uthangarai, Krishnagiri 636902, Tamil Nadu, India.
³ College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, PR China. Electronic address: huangxy04@126.com.

PMID: 34087597
DOI: 10.1016/j.jcis.2021.05.108

Abstract

White light-emitting diodes (LEDs) are widely used in lighting and display devices, and the exploration of phosphors with excellent luminescence performance and good stability is the key to the development of white LEDs. In this work, we reported novel near-UV-excited green-emitting Ca₂LuHf₂(AlO₄)₃:Ce³⁺,Tb³⁺ garnet phosphors with efficient Ce³⁺ → Tb³⁺ energy transfer. The CLHA:Ce³⁺,Tb³⁺ green phosphors were successfully synthesized by a high-temperature solid-state method, and the phosphors were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, photoluminescence excitation and photoluminescence spectra, the Commission International de I'Eclairage (CIE) chromaticity coordinates, quantum efficiency and temperature-dependent emission spectra. Due to the spin-allowed 4f → 5d transition of Ce³⁺ ions, the CLHA:Ce³⁺,Tb³⁺ phosphors exhibited a strong broad excitation band in the 300-470 nm near-ultraviolet (near-UV) range. Under 408 nm excitation, the CLHA:Ce³⁺,Tb³⁺ phosphors showed strong green light with emission center at 543 nm. The mechanism of energy transfer from Ce³⁺ to Tb³⁺ ions was attributed to quadruple-quadruple interaction. Impressively, the internal quantum efficiency and external quantum efficiency of the optimal CLHA:0.02Ce³⁺,0.5Tb³⁺ green phosphors were measured to be 77.1% and 55.8%, respectively. Finally, using the CLHA:0.02Ce³⁺,0.5Tb³⁺ phosphors as green-emitting color converter, a near-UV-pumped white LED device was fabricated, and under 80 mA driving current the LED device demonstrated bright warm-white light with high color rendering index (93.7), low correlated color temperature (3574 K), CIE chromaticity coordinates (0.3922, 0.3633), and high luminous efficacy (29.35 lm/W).

Keywords: Color rendering index; Green phosphors; Rare-earth ions; Solid-state lighting; Thermal stability.