Superior white light emission and color tunability of tri-doped YBO3:Tb3+, Eu3+ and Dy3+ for white light emitting diodes

Abstract

A tri-doped YBO₃:Tb³⁺, Eu³⁺ and Dy³⁺ phosphor, which is capable of producing white light by combining blue, green, yellow, orange and red emissions when excited at 365 nm ultraviolet (UV) light, was developed using a general hydrothermal method. The samples showed strong photoluminescence spectra at 485, 541, 578, 591, 611, and 627 nm under the excitation wavelength of 365 nm (ultraviolet light) indicating the presence of blue, green, yellow, orange and red light due to the transitions ⁴F_9/2 → ⁶H_15/2 (Dy³⁺), ⁵D₄ → ⁷F₅ (Tb³⁺), ⁴F_9/2 → ⁶H_13/2 (Dy³⁺), ⁵D₀ → ⁷F₁ (Eu³⁺) and ⁵D₀ → ⁷F₂ (Eu³⁺), respectively. Tri-doping is seemed to be more successful in the creation of white light. The effect of the variations in doping percentages on color tunability was also evident. Evidence of efficient energy transfers from the host excitations to activators Tb³⁺ and Eu³⁺, and from Dy³⁺ to Tb³⁺ to Eu³⁺ existed. Although there is a weak energy transfer from host to Dy³⁺ occurred, strong photoluminescence excitation bands existed in Dy³⁺.