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New nanosized upconversion oxide materials (2017 - 2020)
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Project leader Tamara Gavrilovic

Agreement No 

Research application No

The goals of this interdisciplinary project proposal are related with the resolution of problems widely investigated in the field of luminescent up-converting nanomaterials, such as: stabilization, modification, (bio)functionalization of the surface and toxicity of materials. The design and preparation of multifunctional nanomaterials with improved performance have aroused considerable interest in recent years. The development of synthetic methods which will provide materials of high purity, crystallinity, uniformity of size, morphology, and composition, is one of the most challenging problems in materials science. Several groups of luminescent up-converting nanomaterials will be produced, coated and modified. Among them are: metal oxides (TiO2, ZnO, ZrO2, HfO2), aluminates (SrAlO4), silicates (SrSiO4) and phosphates (APO4, A = La, Y, Gd, Lu). The properties of these functional nanostructures will be examined from the fundamental point of view; however, adapted for practical applications including needs for specific high-tech products required by Latvian industry. As an example, proposed structures might be employed as solid-state laser amplifiers, as well as for imaging agents, cancer detection and drug delivery. The implementation of this project will be significant not only for scientific research, but also for major society due to diverse potential in physical, biomedical and pharmaceutical applications, and various technical solutions.

Project progress

April 3, 2018

Particle size effects on the structure and emission of Eu3+:LaPO4 and EuPO4 phosphors.

A new publication within ERDF Post Doc project No. which includes detailed study of particle's size effect on structural and luminescent properties of doped phosphate materials has been published.

Tamara Gavrilović, Jovana Periša, Jelena Papan, Katarina Vuković, Krisjanis Smits, Dragana J. Jovanović, Miroslav D. Dramićanin

Rare-earth doped LaPO4 represents an important class of luminescent nanomaterials, has proven to be suitable for production of efficient down-shifting and up-conversion phosphors. The size effect on emission intensities and decays, structure, and morphology were analyzed by steady-state and time-resolved photoluminescence spectroscopy, X-ray diffraction, scanning and transmission electron spectroscopy, and diffuse reflection spectroscopy. It was found that the particle size has significant influence on the structure and luminescent properties of particles. In particular, with a decrease in particle diameter emission bands broaden due to structural disorder and new emission bands from defect states appear in ultrasmall (2 nm) particles. Judd-Ofelt analysis showed that internal quantum yield of Eu3+ emission is strongly influenced by particle's morphology. Journal of Luminescence

Synthesis, structure and spectroscopic properties of luminescent GdVO4:Dy3+ and DyVO4 particles

Joint publication between researchers from Serbia, Latvia, Italy, Poland and Vietnam has been published.

Dragana J. Jovanović, Andrea Chiappini, Lidia Zur , Tamara V. Gavrilović, Thi Ngoc Lam Tran, Alessandro Chiasera, Anna Lukowiak, Krisjanis Smits, Miroslav D. Dramićanin, Maurizio Ferrari

GdVO4:Dy3+ and DyVO4 samples with particles of different morphology and size were prepared by four synthetic methods: high temperature solid-state, co precipitation, reverse micelle and colloidal. The size effect on the structure, Raman active modes, and photoluminescence emission intensities were analyzed by X-ray diffraction, Raman and photoluminescence spectroscopy, scanning and transmission electron microscopy, and diffuse reflection spectroscopy. Due to strong emission in the NIR spectral region, these luminescent GdVO4:Dy3+ and DyVO4 (bulk)particles incorporated in silica waveguides could find potential application for enhancement of 1.3 µm photoluminescence. Optical Materials

All results were orally presented in a frame of Workshop at Institute of Solid State Physics, University of Latvia.

Project progress

January 9, 2018

We are happy to announce that significant progress has been recently accomplished and four different methods for preparation of phosphors based on phosphate and vanadate host were developed and optimized: high temperature solid-state, co-precipitation, reverse micelle and colloidal route.
Samples with particles of different morphology and size with satisfactory luminescent intensity were obtained. At this moment, some of them incorporated in silica waveguides could find potential application for enhancement of 1.3 μm photoluminescence.

The work investigating luminescent lanthanum nanoparticles was presented at international conference ‘’Spectral shaping for biomedical and energy applications’’, SHIFT 2017, 13-17 November, Tenerife, Spain.

The article, with detailed study of nanoparticle’s size effect on structural and optical properties of doped lanthanum and europium phosphate has been accepted for publication, which can be found online. Also, very proud to report that a joint manuscript between our team and researchers from Italy, Vietnam, Poland and Serbia studying phosphors based on vanadate host has been submitted and accepted for publication.

We will continue our work, hopefully acquiring materials with improved performances, and attractive practical applications.