KLaF4:Er an efficient upconversion phosphor

Synthesis of RbREF4 (RE=Pr, Nd, Sm, Eu, and Tb) and RbRE2F7 (Dy, Ho, Er and Yb) under non-aqueous conditions

“…9(d). This behaviour is quite different from the emission behaviour of Er-doped cubic KLaF 4 samples in which the Er 3+ ions are eight coordinated [18]. Intensity of red emission is more as compared to the green in RbEr 2 F 7 and this is reversed in Er-doped KLaF 4 .…”

KLaF4 nanocrystallisation in oxyfluoride glass-ceramics

“…Both shells would constitute a diffusional barrier which limits crystal growth. The presence of K-La-F bonds in the parent glass, confirmed by 19 F NMR, gives rise to the α-KLaF 4 nano-crystals after heat treatment. Moreover, a diffusional process from K-F and Al-F-Al to the K-F-La environments takes place.…”

“…23 A phonon energy of 262 cm −1 has been reported for hexagonal KLaF 4 . 23 Tyagi et al 19 suggested that the advantageous lower phonon energy of KLaF 4 in comparison with NaYF 4 (360 cm −1 ) arises from the greater radii of the alkali-metal ion, whereas the greater size of the rare-earth ion in KLaF 4 as compared to NaYF 4 imparts higher stability. 24 However, to the best of our knowledge, glass-ceramics containing KLaF 4 have not been reported until now.…”

Investigation of Er3+, Yb3+, Nd3+ doped yttrium calcium oxyborate for photon upconversion applications

“…Er 3þ is also having matching energy level ( 4 I 15/ 2 / 4 I 11/2 ) with that of the pump photon 1064 nm. So, there may be chance of upconversion green emission by two photon absorption [20]. The green upconversion efficiency of Er 3þ :Yb 3þ :Nd 3þ :YCOB sample is greater than that of Er 3þ :Yb 3þ :YCOB sample.…”

“…The possibilities by which green light emitting levels 2 H 11/2 and 4 S 3/2 of Er 3þ ion can be populated are energy transfer upconversion and two-step absorption [13,20]. Due to its high absorption of 1064 nm photons, Yb 3þ ion will act as sensitizer.…”