Advanced Fabrication of Phosphor-in-Silica Glass for Stable and High-Power LEDs

ConspectusPhosphor-converted light-emitting diodes (pc-LEDs) have become critically important for various optoelectronic applications, particularly in solid-state lighting systems, backlight displays, night-vision, and bioimaging. Their significance stems from their ability to provide energy-efficient, tunable, and stable light emission across multiple spectral ranges. High-power pc-LEDs are typically fabricated by integrating spectral converters incorporating inorganic phosphors (IPs) onto blue LED chips. This conventional architecture enables efficient wavelength conversion through photoluminescence, where the phosphor layer absorbs a portion of the blue emission and re-emits light at longer wavelengths. The most economically viable and effective approach for synthesizing transparent and chemically durable spectral converters is to encapsulate efficient IP particles within silica glass matrices. The encapsulation by silica glass preserves the phosphors’ luminescence properties while providing superior chemical and thermal stability compared to other inorganic and organic alternatives. However, the fabrication of phosphor-in-silica glass (PiSG) requires applying high-pressure or high-vacuum sintering to densify the composite into a translucent spectral converter with limited sizes and shapes, making the high-throughput fabrication of PiSG challenging. In this Account, we first detail the fabrication of silica glass using both additive manufacturing (AM) and non-AM techniques coupled with pressureless sintering. We then highlight how our group has advanced these methods, particularly 3D stereolithography (SLA) and injection molding (IM) to enable the high-throughput production of translucent, efficient, and chemically durable PiSG spectral converters in which the phosphor-silica interfacial reaction is inhibited. These innovations facilitate the fabrication of stable and high-power white/broadband pc-LEDs. Additionally, we discuss the critical role of IM and pressureless sintering in developing PiSG composites incorporating other IPs, such as long persistent phosphors. Finally, we outline future research directions and key challenges in the development of PiSG based spectral converters, addressing the challenges of scalability and performance optimization for pc-LEDs. The development of these PiSG materials exhibiting exceptional luminescence performance and ultrahigh chemical durability presents a significant advancement in spectral converters for pc-LEDs. We anticipate that this Account will not only facilitate the fabrication of high-power pc-LEDs with extended operational lifetimes but also inspire scientists to explore next-generation pc-LEDs for numerous applications.