Rare Earth Doped Alkali Earth Sulfide Phosphors for White-Light LEDs

Abstract

:Eu and SrS:Eu phosphors were synthesized by solid-state reaction. The effects of doping concentrations on luminescent properties of phosphors are investigated. The samples are excited using electroluminescent blue light emitting diode (460 nm) to examine them as potential coating phosphors for white-light LEDs. The excitation and emission spectra of these phosphors are broadband which can be viewed as the typical emission of Eu 2+ ascribed to the 4f-5d transitions. Because of their broadband absorption in the region 400-630 nm, these phosphors meet the application requirements for blue LED chips. A white-light LED was fabricated through the integration of a 460 nm chip. The results indicate that these phosphors can be considered as candidates for the application in blue LED chip-based white-light LEDs.

Synthesis and Luminescent Properties of Strontium Cerium Oxide Phosphors Doped with Rare Earths

“…Some authors [8][9][10] have assigned the luminescence of the Sr 2 CeO 4 material to the charge transfer between Ce 4+ and O 2because the position and shape of the absorption band and the emission band width are characteristic for this type of transition. Some authors have observed that the strong luminescence of Sr 2 CeO 4 makes it potentially applicable as blue phosphor material in low pressure mercury vapor lamps [11] and FED [12,13] as well as other types of luminescence devices [14]. Following this observation, several studies about this luminescent material have been conducted, and some synthetic routes have been developed for the preparation of Sr 2 CeO 4 powders.…”

ZnS Nanoparticles‐decorated Composite Graphene Paper: A Novel Flexible Electrochemical Sensor for Detection of Dopamine

“…Recently, metallic sulfides are one of the most researched materials due to possessing higher electrical conductivity and electrochemical activities through easy junction control and self‐ doping in photocatalytic applications [31], supercapacitors [32], light‐emitting diodes [33], gas detection systems [34] as well as lithium‐ion [35], and sodium‐ion batteries [36]. Among the metal sulfides, ZnS is one of the frequently studied nanomaterials owing to broadband energy, high electrochemical activity, electrical conductivity, abundant porous structure, the high density of active sites, and owning to various morphology according to the synthesis process [37–40].…”

Tuning of Emission Wavelength of CaS:Eu by Addition of Oxygen Using Atomic Layer Deposition

“…More specifically, the ability of shifting the peak emission of calcium sulfide doped with europium (CaS:Eu), a well-known red emitting inorganic phosphor material. CaS:Eu luminescent characteristics have been widely studied and used in a variety of applications such as, medical imaging [15,16], cell labeling [17], white-light-emitting diodes [18,19] and electroluminescent devices [20][21][22][23]. The red emission in CaS:Eu is originated from the Eu divalent state of ionization (Eu 2+ ) and its broad emission is caused by electron transition from the lower 4f 6 5d 1 state to the 4f 7 ground state [24].…”

“…However, we present a study where the tuning is performed by adding oxygen anions reinforcing the idea that ALD can be used to modify the vicinity of the dopant elements. These materials fabricated by ALD can thus be used for applications where the fine color tuning is advantageous such as: red electroluminescent devices [20][21][22][23]28], white-light-emitting diodes [18,19] solar cells [29], and lasers [6,8,30].…”