NIR fluorescence quenching by OH acceptors in the Nd3+ doped KY3F10 nanoparticles synthesized by microwave-hydrothermal treatment

作者：Orlovskii Yu V; Vanetsev A S; Keevend K; Kaldvee K; Samsonova E V; Puust L; del Rosal B; Jaque D; Ryabova A V; Baranchikov A E; Lange S; Sildos I; Kikas J; Loschenov V B

来源：Journal of Alloys and Compounds, 2016, 661: 312-321.

DOI：10.1016/j.jallcom.2015.11.156

• Nd3+: KY3F10 nanoparticles
• Microwave-hydrothermal synthesis
• Near IR fluorescence
• Fluorescence quenching
• OH acceptors
• Fluctuation kinetics

We performed site-selective spectroscopy and analyzed static (Direct Energy Transfer, DET) Forster kinetics of impurity quenching N(t) in the water-dispersible 0.1% Nd3+: KY3F10 nanoparticles (NPs) synthesized by microwave-hydrothermal treatment (MWHT) to determine the acceptor space dimension D and estimate the concentration of -OH acceptors. As a result we found two types of optical sites for Nd3+ ions and revealed that a moderate amount of -OH quenching acceptors is distributed in the volume of the nanoparticles, rather than on their surface. The result is similar to the one obtained for the previously studied water-dispersible the Nd3+: KYF4 and Nd3+: YPO4 NPs, and thus may be extended to all nanoparticles synthesized by water-based techniques. Therefore, all of the previously obtained results concerning the fluorescence quenching of such NPs should be reviewed in the light of the new data on the actual source of the quenching. Also, we compared quantitatively the near IR fluorescence quenching in the Nd3+: KY3F10 NPs with that in the Nd3+ doped KYF4 and YPO4 nanoparticles with close sizes and size distribution (all the nanoparticles were synthesized by MWHT). We found minimum fluorescence quenching and accordingly maximum fluorescence quantum yield for the Nd3+: KY3F10 nanocrystals, which is in agreement with the relative amount of -OH molecular groups in the volume of the NPs estimated from Forster kinetics and with the results of TG/DTG-DTA data analysis. The analysis of the fluorescence kinetics of the 1% Nd3+: KY3F10 NPs revealed the realization of the late fluctuation stage. The formation of the fluctuation stage confirmed the high concentration of the -OH acceptors in the volume of the NPs compared to the optically active Nd3+ ions. Furthermore, the analysis of the fluctuation stage confirmed the reduced -OH concentration in the Nd3+ doped KY3F10 NPs in comparison with the KYF4 and YPO4 NPs. This makes the Nd3+: KY3F10 NPs especially promising material for near IR imaging.

• 出版日期2016-3-15