Energy transfer mediated single-phased white light emission in Bi3+-Eu3+ codoped Ba3YGa2O7.5 for WLED

Novel color tunable LaCaGaO4:Bi3+,Eu3+ phosphors for high color rendering warm white LEDs

“…The two primary components of the PLE spectrum observed at 613 nm are a wide peak centered at 252 nm and multiple sharp peaks in the 400–500 nm range. The former is attributed to the charge transfer band from the 2p 6 orbital of the O 2– ions to the 4f 6 orbital of the Eu 3+ ions, while the latter is a result of the distinctive 7 F 0 → 5 L 6 and 7 F 0 → 5 D 2 transitions of the Eu 3+ ions 15,32,33 . Under 252 nm light excitation, the LCGO:0.02Eu 3+ sample shows a series of sharp line emissions in the range from 500 to 725 nm.…”

“…The former is attributed to the charge transfer band from the 2p 6 orbital of the O 2ions to the 4f 6 orbital of the Eu 3+ ions, while the latter is a result of the distinctive 7 F 0 → 5 L 6 and 7 F 0 → 5 D 2 transitions of the Eu 3+ ions. 15,32,33 Under 252 nm light excitation, the LCGO:0.02Eu 3+ sample shows a series of sharp line emissions in the range from 500 to 725 nm. The distinctive 5 D 1 → 7 F 0 and 5 D 0 → 7 F J (J = 0-4) transitions of the Eu 3+ ions are what cause these emission peaks.…”

“…It is feasible to perform luminescence color modulation and create w‐LED devices with high R a and low CCT by varying the ratio of trichromatic phosphors. However, the use of multiple phosphors not only increases the manufacturing cost but also tends to produce reabsorption of emissions 15 . To produce many luminous centers emanating from a single substrate, one viable method is to build an energy transfer between the sensitizer and activator.…”

“…However, the use of multiple phosphors not only increases the manufacturing cost but also tends to produce reabsorption of emissions. 15 To produce many luminous centers emanating from a single substrate, one viable method is to build an energy transfer between the sensitizer and activator.…”

Moderate Trap Engineering for Enhanced Thermal Stability and High Efficiency in a Bi3+-Doped Phosphor

“…Ce 3+ , Eu 2+ , and Bi 3+ are three activators with parity-allowed transitions that can be effectively excited by the n-UV lights and then emit adjustable light in the visible region. – Among them, Bi 3+ -doped phosphors can be synthesized without a reducing atmosphere, which is favorable for safety and economics. In addition, Bi 3+ -doped phosphors usually have a larger Stoker shift, which can effectively reduce the reabsorption effect. – Therefore, Bi 3+ -doped phosphors have received extensive attention for LED lighting. – However, inadequate thermal stability is a significant issue for the Bi 3+ -doped phosphors, as most of them lose more than 30% of their room-temperature emission at 423 K. – The serious thermal quenching (TQ) effect greatly limited the practical application of Bi 3+ -doped phosphors in LED lighting, where the chip will inevitably generate heat during operation.…”