Ojha N, Tuomisto M, Lastusaari M, Petit L
Laboratory of Photonics, Tampere University of Technology FI-33101 Tampere Finland
University of Turku, Department of Chemistry FI-20014 Turku Finland.
RSC Adv. 2018 May 24;8(34):19226-19236. doi: 10.1039/c8ra03298j. eCollection 2018 May 22.
The direct doping method was applied to fabricate upconverter fluorophosphate glasses in the system (90NaPO-(10-)NaO-NaF) (mol%) by adding NaYF:Er,Yb nanocrystals. An increase in the network connectivity, a red shift of the optical band gap and a decrease in the thermal properties occur when NaO is progressively replaced by NaF. To ensure the survival and the dispersion of the nanocrystals in the glasses with = 0 and 10, three doping temperatures ( ) (525, 550 and 575 °C) at which the nanocrystals were added in the glass melt after melting and 2 dwell times (3 and 5 minutes) before quenching the glasses were tested. Using 5 wt% of the NaYF:Er,Yb nanocrystals, green emission from the NaYF:Er,Yb nanocrystals-containing glasses was observed using a 980 nm pumping, the intensity of which depends on the glass composition and on the direct doping parameters ( and dwell time). The strongest upconversion was obtained from the glass with = 10 prepared using a of 550 °C and a 3 min dwell time. Finally, we showed that the upconversion, the emission at 1.5 μm and of the transmittance spectra of the nanocrystals-containing glasses could be measured to verify if decomposition of the nanocrystals occurred in glass melts during the preparation of the glasses.
采用直接掺杂法，通过添加NaYF:Er,Yb纳米晶体，在(90NaPO-(10-)NaO-NaF)（摩尔%）体系中制备上转换氟磷酸盐玻璃。当NaO逐渐被NaF取代时，网络连通性增加，光学带隙发生红移，热性能降低。为确保纳米晶体在 = 0和10的玻璃中存活和分散，测试了三种掺杂温度（ ）（525、550和575 °C），即在玻璃熔体熔化后添加纳米晶体，并在淬火前设置2个保温时间（3和5分钟）。使用5 wt%的NaYF:Er,Yb纳米晶体，在980 nm泵浦下观察到含NaYF:Er,Yb纳米晶体玻璃的绿色发射，其强度取决于玻璃组成和直接掺杂参数（ 和保温时间）。使用550 °C的 和3分钟保温时间制备的 = 10的玻璃获得了最强的上转换。最后，我们表明，可以测量含纳米晶体玻璃的上转换、1.5 μm处的发射和透过率光谱，以验证在玻璃制备过程中纳米晶体在玻璃熔体中是否发生分解。
