Jagannath G, Eraiah B, Jayanthi K, Keshri Shweta Rani, Som Sudipta, Vinitha G, Pramod A G, Krishnakanth K N, Devarajulu G, Balaji Sathravada, Venugopal Rao S, Annapurna K, Das Subrata, Allu Amarnath R
Department of Physics, Bangalore University, Bengaluru, Karnataka 560056, India.
Peter A. Rock Thermochemistry Laboratory and Neat ORU, University of California, Davis, Davis, CA 95616, USA.
Phys Chem Chem Phys. 2020 Jan 28;22(4):2019-2032. doi: 10.1039/c9cp05783h. Epub 2020 Jan 6.
Alkali borate glasses activated with trivalent europium ions and rooted with gold (Au) nanoparticles (NPs) were synthesised through a melt quenching process involving a selective thermochemical reduction and their applicability as photonic materials was assessed in detail. Non-linear optical (NLO) measurements were performed using a Z-scan approach in the wavelength range of 700-1000 nm. The open aperture Z-scan signatures for the Eu-containing glasses embedded with and without the Au NPs established a reverse saturable absorption (RSA) at all of the studied wavelengths ascribed to the two-photon absorption (2PA). Surprisingly, the nonlinear optical absorption switched to a saturable absorption (SA) with an increase in the concentration of AuCl. With the incorporation of the Au NPs, the UV excited photoluminescence (PL) intensity of the Eu-doped glasses increased first as a consequence of the local field enhancement by the Au NPs, and subsequently decreased at a higher concentration of AuCl due to the reverse energy transfer from the Eu ion to the Au NPs. The electronic polarization effect of the host glass enhanced the D→F transition intensity on the incorporation of the gold NPs owing to the gold NP-embedded glasses showing a deep-red emission. The NLO and PL studies suggested that the investigated glasses containing a 0.01 mol% of AuCl is practically appropriate for photonic applications.
通过涉及选择性热化学还原的熔体淬火工艺合成了用三价铕离子激活并固定有金（Au）纳米颗粒（NPs）的碱金属硼酸盐玻璃，并详细评估了它们作为光子材料的适用性。使用Z扫描方法在700 - 1000 nm波长范围内进行非线性光学（NLO）测量。对于嵌入和未嵌入Au NPs的含铕玻璃，开孔Z扫描特征在所有研究波长下都显示出归因于双光子吸收（2PA）的反饱和吸收（RSA）。令人惊讶的是，随着AuCl浓度的增加，非线性光学吸收转变为饱和吸收（SA）。随着Au NPs的掺入，由于Au NPs的局部场增强，Eu掺杂玻璃的紫外激发光致发光（PL）强度首先增加，随后在较高浓度的AuCl下由于从Eu离子到Au NPs的反向能量转移而降低。由于嵌入Au NPs的玻璃呈现深红色发射，主体玻璃的电子极化效应增强了掺入金纳米颗粒时的D→F跃迁强度。NLO和PL研究表明，含有0.01 mol% AuCl的研究玻璃实际上适用于光子应用。
