NIR-to-visible and NIR-to-NIR upconversion in lanthanide doped nanocrystalline GdOF with trigonal structure

Abstract

particles were prepared in aqueous solution by a simple coprecipitation method and a suitable heat treatment at 500°C. From the experimental X-Ray powder diffraction patterns, a Rietveld analysis was carried out and it was determined that the nanoparticles are single phase trigonal GdOF. Electron microscopy images show that the average particle size is approximately 25 nm, even though a certain degree of agglomeration is evidenced. The spectroscopic properties of the lanthanide doped nanoparticles are investigated in terms of emission spectra. For proper lanthanide concentrations, the nanoparticles show visible upconversion upon excitation at 980 nm, making them useful as luminescent nanomaterials for photonic applications.

Synthesis, morphology and spectroscopic properties of red-luminescent rhombohedral YOF: Yb3+, Er3+ powders

“…11. 31,32 Luminescent decay curves of 2 H 11/2 / 4 I 15/2 and 4 F 9/2 / 4 I 15/2 transition of Er 3+ in different samples are recorded by monitoring the emissions at 536 nm and 672 nm, respectively. The change of the emission intensity is not obvious when the temperature increases from 400 C to 500 C, which can be explained by the similar morphologies and crystallinity of the YOF: Yb 3+ , Er 3+ @400 C and YOF: Yb 3+ , Er 3+ @500 C products.…”

“…The Yb 3+ ion would transfer its energy to Er 3+ ion by 2 F 5/2 / 2 F 7/2 (Yb 3+ ): 4 I 15/2 / 4 I 11/2 (Er 3+ ) process to make the Er 3+ populate 4 I 11/2 level, this is the energy transfer procedure 1 presented in Fig. 31,40 It can be seen that both of the red and green emissions of Er 3+ are relevant to a two photons absorption process. When excited to 4 I 11/2 level, Er 3+ ion will relax to the long lifetime lower lying level 4 I 13/2 by multiphonon emitting procedure.…”

Infrared to infrared upconversion emission in Pr3+/Yb3+ co-doped La2O3 and La(OH)3 nano-phosphors: A comparative study

“…It is interesting to note that there is very small change in the emission intensity in NIR region in this host compared to La 2 O 3 whereas for other colours it is reduced to half. The intense NIR emission on NIR excitation has large applications [20][21][22]. This emission arises due to excited to excited state transition where upper state is populated by the cooperative upconversion.…”

“…Only in few reports the upconversion in infrared to infrared regions have been observed [12,16,19]. Infrared to infrared upconversion emission have been studied by the several workers [20][21][22]. Since the study on infrared to infrared upconversion is very limited, therefore, it needs further attention.…”

Preparation and upconversion luminescence characterization of 12CaO·7Al2O3:Ho3+/Yb3+ polycrystals

“…The valence‐electron configuration of Ho 3+ is 4f 10 , 4f electrons can achieve energy transition in the electron shell itself, the outer 10 electrons of Ho 3+ have many different transition routes, the fluorescence effects include green‐light emission ( 5 F 4 / 5 S 2 → 5 I 8 ) and red‐light emission ( 5 F 5 → 5 I 8 ). Esterowitz et al discovered the sensitization of Ho 3+ quantum counter action by Yb 3+ in CaF 2 , and under 980‐nm excitation, Yb 3+ has big absorption cross sections, Ho 3+ is easily sensitized by Yb 3+ , so we choose Ho 3+ as the emitting ion of green and red light .…”