Preparation and luminescent properties of (Ca1-x,Srx)S:Eu2+ red-emitting phosphor for white LED

Luminescence properties of SrSi2O2N2 doped with divalent rare earth ions

“…Mixtures of SrCO 3 (Philips Lighting Components, 99.9%), Si 3 N 4Àx (NH) 3/2x (x % 1, made by thermal decomposition of Si(NH) 2 as described in Ref. [14], O contento2 wt%), and the rare earth dopants Eu 2 O 3 (Alfa Aesar, REacton 99.999%) or Yb 2 O 3 (Auer-Remy, 99.99%) were prepared by ball milling, and fired for 2-4 h at 1200-1500 1C in a reducing atmosphere (H 2 /N 2 ) in a tube furnace.…”

“…Doping such materials with Ce 3+ or Eu 2+ can lead to strong absorption in the near-UV to blue spectral range combined with efficient emission in the visible. For example, oxides like Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) or sulfides like CaS:Eu 2+ are currently applied in phosphor-converted LEDs (pcLEDs) as luminescence converters [1,2]. Nevertheless, pronounced temperature quenching of luminescence and low chemical stability restricts their use in LED lighting applications where a long device life time under harsh conditions is required.…”

Preparation, Characterization and Photoluminescence Properties of Ca1-xSrxS:Eu Red-emitting Phosphors for a White LED

“…17 Since the lattice parameter of SrS:Eu is larger than that of CaS:Eu, the distance between the Eu 2+ ion and S 2− ions in SrS:Eu is longer than that in CaS:Eu. Increasing the distance between the Eu 2+ ion and S 2− ions will decrease the crystal strength, which should lead to a decrease in the energy difference between T 2g and E g states of the 4f 1 (T 2g ) state to the 4f 7 ( 8 S 7/2 ) ground state.…”

“…[12][13][14][15] CaS:Eu and SrS:Eu are good red-emitting candidate phosphors for three-band phosphor-converted white LEDs pumped by blue LEDs, since both phosphors have a strong absorption at 455 nm due to the 4f → 5d transitions of the doping Eu. 16,17 The emission peaks of Ca 1-x Sr x S:Eu are located from 618 to 655 nm, and correspond to the transition from the lower 4f 6 5d 1 (T 2g ) state to the 4f 7 ( 8 S 7/2 ) ground state. However, relatively little is known about the optical properties of solid solutions of CaS:Eu and SrS:Eu phosphors for use in lighting applications.…”

Optical properties of flexible fluorescent films prepared by screen printing technology

“…[1][2][3][4] Nowadays, the white LEDs were mainly fabricated by the phosphor converted and multi-chips combination method. [5][6][7] The commercial white LEDs are fabricated by combing the blue Ga(In)N chip with yellow Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) phosphor, in which the silicone yellow phosphor YAG: Ce are coated on the blue chip to emit white light. However, this phosphor-converted technique has several disadvantages, such as, poor heat dissipation of LED chip and uniformity of white light emission, serious scattering phenomenon and so on.…”