Blue‐Light‐Excited Cyan‐Emitting Carbon‐Dot‐Ormosil Gel for Blue‐Overshoot Mitigation and Cyan‐Gap Bridging in WLEDs

ABSTRACT Currently, the primary method for manufacturing white light‐emitting diodes (WLEDs) involves pairing blue‐emitting InGaN LED chips with a yellow‐emitting phosphor coating or complementary green and red phosphors. However, the light spectrum from these WLEDs typically features a “blue overshoot” (within 440 – 460 nm, posing potential health hazards to the retina) and a “cyan gap” (spanning 470 – 520 nm, diminishing color‐rendering ability). Achieving uniform dispersion of these phosphors presents another challenge during the WLED encapsulation process. In this context, we propose a strategy to “kill three birds with one stone” by preparing a blue‐light‐excited cyan‐emitting carbon‐dot (CD)‐Ormosil gel. The glass derived from this gel exhibits a strong absorption band at 450 nm and photoluminescence peaks at 485 and 520 nm, thereby reducing the “blue overshoot” and filling the “cyan gap” in the WLED's spectrum. Furthermore, the CD‐Ormosil gel demonstrates excellent compatibility with commercial phosphors, making it an ideal encapsulating material for WLED devices. Therefore, the development of this cyan‐emitting CD‐Ormosil gel holds great promise to address the issues of blue overshoot, cyan gap, and phosphor encapsulation in WLED technology, paving the way for more efficient, healthier, and visually appealing lighting solutions.