Enhanced blue and green upconversion in hydrothermally synthesized hexagonal NaY1−xYbxF4:Ln3+ (Ln3+ = Er3+ or Tm3+)

Preparation and characterization of upconversion luminescent NaYF4:Yb, Er (Tm)/PS bulk transparent nanocomposites through in situ polymerization

“…Owing to the favorable electronic energy level schemes with equally spaced and long-lived excited states and being accessible under IR radiation, both Er 3+ and Tm 3+ ions are ideally suitable to convert infrared to visible light. Yb 3+ ions are added as sensitizer which can greatly enhance the infrared to visible upconversion efficiency due to the energy transfer from Yb 3+ to Er 3+ (or Tm 3+ ) [29]. Recently, some groups have introduced NaYF 4 :Yb 3+ , Er 3+ into polymer matrix to synthesize bulk nanocomposites [30][31][32].…”

Monodisperse and core–shell structured NaYF4:Ln@SiO2 (Ln=Yb/Er, Yb/Tm) microspheres: Synthesis and characterization

“…Recently, infrared-to-visible up-conversion phosphors with low optical background, high photo-stability and reduced instrument cost have been the subject of intensively research [31][32][33][34][35][36][37][38][39][40][41][42]. Upconversion phosphors could emit a higher energy photon after absorbing two lower energy excitation photons on the basis of sequential adsorption and energy-transfer steps [43].…”

Upconversion properties of Nd3+–Yb3+–Ho3+-doped β-Na(Y1.5Na0.5)F6 powders

“…As the rare-earth doped phosphors is concerned, hexagonal NaYF 4 is proved as one of the most efficient host for green, blue and red upconversion due to its low phonon energy and high chemical stability [16][17][18][19]. In this work, we report the upconversion luminescence of Ho 3+ in Nd 3+ -Yb 3+ -Ho 3+ -dopedˇ-Na(Y 1.5 Na 0.5 )F 6 powders under 808 nm and 980 nm excitations.…”