Upconversion Luminescence Er–Yb–Bi Codoped Transcarpathian Clinoptilolite
Year: 2026
Type: conference-paper
Abstract: Zeolites are promising materials for the creation of new materials with optically active centers, as their structure contains Si–O–Al and Si–O–Si groups with low-energy vibrations, and their pores can be used to accommodate cations, in particular, rare earth elements. There are luminophores based on synthetic zeolites doped with lanthanides, which operate via an upconversion mechanism in which lower-energy light is converted into higher-energy light through multiphoton absorption and energy transfer processes. Compared to low-conversion luminescent (LM) materials, LM upconversion labels demonstrate intriguing advantages, such as very low background light, high penetration depth, high detection sensitivity, and low photodamage to biological samples. The most effective upconversion LM materials are based on the Er3+ion in combination with the Yb3+ion as a sensitiser, which exhibits green and red emission. The presence of Bi can enhance the efficiency of the upconversion luminophore, as this metal can act as an excellent material for blocking and sealing zeolite pores, thereby protecting the optically active centers from LM quenching. A natural zeolite-containing mineral from the deposit in the village of Sokirnytsia in the Ukrainian Transcarpathian region was used in the current study. Transcarpathian clinoptilolite (CL) is an effective sorbent for rare earth elements. During the synthesis of upconversion LM materials based on the CL–Bi(III)– Er(III)–Yb(III) composition, the results of studies on the sorption properties of CL with respect to Yb(III), Er(III), and Bi(III) were utilised. A Yb laser with a power of 3 W (λ = 980 nm) was used to excite the upconversion LM. In the upconversion LM spectra of samples based on Transcarpathian CL, in addition to the peaks at λ = 633 nm and 539 nm, which correspond to red and green emission, two further peaks are clearly visible at λ = 492 nm and λ = 380 nm. Moreover, the highest LM intensity is observed at λ = 492 nm.For the first time, a mechanism has been proposed for the effect of bismuth activation in various forms of its cationic hydroxo complexes on controlling the upconversion LM intensity of natural zeolite-based composites, particularly the 492 nm band. This is relevant to the development of white-emitting phosphors by influencing the intensities of the emission components. The LM intensity at λ = 380 nm is minimal for samples that dwto not contain Ві. The absolute Yb content is of key importance for LM in this spectral region. At λ = 492 nm, the intensity of samples without Bi is very high; however, with equal Er and Yb contents, the presence of Bi enhances the LM. The Yb content in the samples has virtually no effect on the LM intensity at λ = 539 nm. The efficiency of green emission increases with an increase in the Yb/Er ratio. The intensity of LM at λ = 633 nm is even slightly reduced if the samples contain Bi. An increase in the Er content in the samples leads to a decrease in the intensity of red emission. (5 зауваження) The upconversion LM materials we have synthesised and investigated can be used as quantum dot-labelled nanoparticles in vitro cell cultures. Upon irradiation of such biomaterials, they degrade much more slowly than their organic counterparts, i.e., they possess high photostability. Furthermore, they exhibit low overall toxicity to living organisms.
Institution: Lviv University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7225754613