ABSTRACT
Future generations of solid-state lighting (SSL) will prioritize the development of innovative luminescent materials with superior characteristics. The phosphors converted into white light-emitting diodes (white LEDs) often have a blue-green cavity. Cyan-emitting phosphor fills the spectral gap and produces "full-visible-spectrum lighting." Full-visible spectrum lighting is beneficial for several purposes, such as light therapy, plant growth, and promoting an active and healthy lifestyle. The design of cyan garnet-type phosphors, like Ca2LuHf2Al3O12 (CLHAO), has recently been the subject of interest. This review study reports a useful cyan-emitting phosphor based on CLHAO composition with a garnet structure to have a cyan-to-green emitting color with good energy transfer. It could be employed as cyan filler in warm-white LED manufacturing. Due to its stability, ability to dope with various ions suitable for their desired qualities, and ease of synthesis, this garnet-like compound is a great host material for rare-earth ions. The development of CLHAO cyan-emitting phosphors has exceptionally high luminescence, resulting in high CRI and warm-white LEDs, making them a viable desire for LED manufacturing. The development of CLHAO cyan-emitting phosphors with diverse synthesis techniques, along with their properties and applications in white LEDs, are extensively covered in this review paper.
ABSTRACT
Perovskite nanocrystals (NCs) feature adjustable bandgap, wide absorption range, and great color purity for robust perovskite optoelectronic applications. Nevertheless, the absence of lasting stability under continues energization, is still a major hurdle to the widespread use of NCs in commercial applications. In particular, the reactivity of red-emitting perovskites to environmental surroundings is more sensitive than that of their green counterparts. Here, we present a simple synthesis of ultrathin ZrO2coated, Sr2+doped CsPbBrI2NCs. Introducing divalent Sr2+may significantly eliminate Pb° surface traps, whereas ZrO2encapsulation greatly improves environmental stability. The photoluminescence quantum yield of the Sr2+-doped CsPbBrI2/ZrO2NCs was increased from 50.2% to 87.2% as a direct consequence of the efficient elimination of Pb° surface defects. Moreover, the thickness of the ZrO2thin coating gives remarkable heat resistance and improved water stability. Combining CsPbSr0.3BrI2/ZrO2NCs in a white light emitting diode (LED) with an excellent optical efficiency (100.08 lm W-1), high and a broad gamut 141% (NTSC) standard. This work offers a potential method to suppress Pb° traps by doping with Sr2+and improves the performance of perovskite NCs by ultrathin coating structured ZrO2, consequently enabling their applicability in commercial optical displays.
ABSTRACT
Single-phase white light-emitting Ca x Ba(9-x)Lu2Si6O24:Eu2+/Mn2+ codoped phosphors were successfully synthesized, and their photoluminescence properties were experimentally determined. The analysis of the experimental results suggests that the partial substitution of Ba2+ ions by smaller Ca2+ ions alters the distribution of the Eu2+ luminescence center among the three available Ba2+ sites in the host lattice, which enables the emission to be efficiently tuned from blue to blue-green-yellow region. The incorporation of Mn2+ ions resulted in a red light emission at around 618 nm, through energy transfer from Eu2+ to Mn2+ ions via dipole-dipole interactions. The incorporation of Ca2+ and Mn2+ ions also resulted in improved thermal stability. The results qualify the produced Ca x Ba(9-x)Lu2Si6O24:Eu2+/Mn2+ composition as a potential ultraviolet-convertible white light-emitting phosphor.
