Introducing cation disorder to enhance thermal stability in LuY3(BO3)4: Eu3+ phosphors for pc-WLEDs

Thermal quenching is a serious drawback that limits the application of phosphor-converted white light-emitting diodes (pc-WLEDs), because the operating temperature of phosphors tends to increase, resulting in emission loss due to non-radiative transitions. Herein,by introducing Lu3+ ions and Eu3+ ions into YBO3 to create lattice distortion and cation disorder, a series of Lu1-xY3(BO3)4: xEu3+ red phosphors have been designed to obtain novel phosphors with excellent thermal stability. The phosphors were synthesized by the traditional high-temperature solid-phase method. XRD results and EDS energy spectrum access the phase composite and crystal structure. Under 393 nm excitation, Lu1-xY3(BO3)4: xEu3+ phosphors emit red light peaking at 594 nm, 613 nm, and 651 nm Lu0.6Y3(BO3)4:0.4Eu3+ and Lu0.2Y3(BO3)4:0.8Eu3+ can maintain 93% and 86% emission intensity respectively at 150 °C, and they can still maintain 90.2% and 78% respectively at 200 °C. Thermoluminescence spectroscopy proves that the Lu0.2Y3(BO3)4:0.8Eu3+ phosphor has deep defects at 145 °C and 400 °C, which can release electrons to compensate for the emission intensity at high temperatures, thereby improving thermal stability.The prepared phosphor has extremely high thermal stability and particularly high color rendering purity (99.8%). Under the driving current of 120 mA, the color rendering index of the pc-WLED packaged with Lu0.2Y3(BO3)4:0.8Eu3+ phosphor powder is 89.4, and the correlated color temperature is 4681K.All these results indicate that LuY3(BO3)4:Eu3+ phosphors are promising for pc-WLED applications, especially for applications requiring high temperature operating conditions.