News

A publication in Materials & Design presenting a novel method of phosphorescent strontium aluminate coating preparation on aluminum

We are proud to announce that a new publication “Novel method of phosphorescent strontium aluminate coating preparation on aluminum” has been written and published in Materials & Design in October. This publication was funded by the ERDF project “Phosphorescent coatings prepared by plasma electrolytic oxidation” No: Nr.1.1.1.1/16/A/182.

Novel method of phosphorescent strontium aluminate coating preparation on aluminum

Teksta latviskotā versija pieejama http://www.lum.lv/publikacija-par-jaunu-metodi-fosforiscejoso-parklajumu-izveidei-uz-aluminija-virsmas/

Participation in AMT and LumDeTr

In August we participated in the student oriented conference AMT (Advanced Materials and Technologies) in Palanga, Lithuania, presenting multiple posters and attending the lectures.

Just last week we also participated in the LumDeTr (Luminescent Detectors and Transformers of Ionizing Radiation) conference in Prague, Czech Republic. We would like to acknowledge the Mobility Financial Support received from the Faculty of Physics, Mathematics and Optometry, University of Latvia, which partially funded the attendance of this conference.

The search for defects in undoped SrAl2O4 material

A new publication in the frame of ERDF Project Nr.1.1.1.1/16/A/182 on fundamental processes in phosphorescent materials has been published.

Virginija Vitola, Donats Millers, Krisjanis Smits, Ivita Bite, Aleksejs Zolotarjovs

SrAl2O4:Eu,Dy is a very efficient long afterglow phosphor with wide range of possible applications. The luminescence properties and the possible luminescence mechanism of this material have been studied extensively, but there is almost no information available about the undoped material. Therefore, this article deals with the luminescence and thermally stimulated luminescence of an undoped SrAl2O4, revealing the possible defects that might be involved in the creation of the long afterglow in doped material. We conclude that undoped material exhibits some luminescence under X-ray irradiation in low temperature; close to room temperatures luminescence is almost fully thermally quenched in comparison to low temperatures. We can observe F and F2 center luminescence as wellas trace metal luminescence inthe emission spectrum.TSL glow curveyields the peaksthat are close to those observed in material with Eu and Dy doping; therefore these peaks are clearly related to intrinsic defects. The peak at around 400K, that is shifting with rare earth doping, might be due to dopant interaction with intrinsic defects.

Published in Optical Materials

Download PDF

Teksta latviskotā versija pieejama šeit: http://www.lum.lv/defektu-noteiksana-nedopeta-sral2o4-materiala/

Update on ERDF Project Nr.1.1.1.1/16/A/182

ERDF Project Nr.1.1.1.1/16/A/182:

A significant improvement on the control of various electrical parameters was achieved in the last couple of months due to the planned upgrades of the power supply unit. New limits of coating preparation can be achieved now with higher voltages (up to 1000V) as well as with vastly improved software and automated control algorithms allowing uninterrupted change of any desired parameter in time. This modification allows the in-depth studies of effects of high voltage on coating formation process and implementation of RE ions in it. In addition, the stability of the power supply was improved allowing extra-long processing time on high loads. This is important for the different oxide phase formation as recrystallisation occurs only at longer processing times.

With the new setup a new set of samples was prepared and further optimization of parameters is undergoing. The main aim is to improve PEO coating to match and exceed the performance of similar materials in other forms.

Teksta latviskotā versija ir atrodama šeit.

X-ray excited luminescence of SrAl2O4:Eu,Dy at low temperatures

A new publication in the frame of ERDF Project Nr.1.1.1.1/16/A/182 on fundamental processes in phosphorescent materials has been published.

V. Liepina, D. Millers * , K. Smits, A. Zolotarjovs, I. Bite

SrAl2O4:Eu,Dy is a very efficient long afterglow phosphor with wide range of possible applications. In this study we carried out the study of X-ray excited luminescence of SrAl2O4:Dy and SrAl2O4:Eu,Dy samples, including the measurements of afterglow at low temperatures within extended time scale. We observed both Eu and Dy luminescence peaks in the afterglow and TSL measurements. In recent articles the tunneling of electron from trap levels to excited Eu luminescence center was discussed, and in this research we conclude that under X-ray irradiation Eu2+ and Dy3+ serve as hole traps; electron tunneling is present in both SrAl2O4:Eu, Dy and SrAl2O4: Dy, and luminescence afterglow at 10 K arises from decay of excited Eu2+ and Dy3+ centers created via electron tunneling from host trap to Eu3+ and Dy4+ ions.

Journal of Physics and Chemistry of Solids

pdf-iconDownload PDF

Teksta latviskotā versija pieejama šeit: http://www.lum.lv/rentgenstarojuma-ierosinata-sral2o4-luminescence-zemas-temperaturas/

UPDATES for ERDF Post Doc project No. 1.1.1.2/VIAA/1/16/215: Novel nanosized upconverting oxide materials for practical applications

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
pplication 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. https://doi.org/10.1016/j.jlumin.2017.12.002 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.

Teksta latviskotā versija: http://www.lum.lv/jaunumi-eraf-post-doc-project-no-1-1-1-2viaa116215-jauni-nanoizmeru-oksidu-materiali-ar-upconversion-luminiscenci/

Project ERDF Project Nr.1.1.1.1/16/A/182: Phosphorescent coatings prepared by plasma electrolytic oxidation update

PEO A certain project milestone has been recently achieved and luminescent coatings with sufficient luminescence intensity to be seen by the naked eye have been acquired. We will continue our work on intensity and luminescence afterglow parameter improvement and it certainly looks like we’re moving in the right direction although of course there’s tons of work still ahead of us.

A publication studying optical properties of strontium aluminate has been submitted and is being reviewed.

We’re also happy to announce that starting September Boriss Poļakovs and Krišjānis Auziņš have joined the project and are actively working to contribute to project’s successful ongoing.

Improvements on PEO reactor chamber (see photo) have been  made to insure better repeatability and constant results, allowing to study the coatings with greater detail and less errors. Technical improvements have also been made to aluminum samples – it is now possible to split the samples into smaller pieces with absolutely no potential damage to the coating.

Teksta latviskotā versija pieejama šeit. 

 

Taking part in the new COST Actions

Our leading researcher, Krisjanis Smits, was entitled to represent Latvia in two COST actions:

             1.CA COST Action CA16215
             European network for the promotion of portable, affordable and simple analytical platforms

             2.CA COST Action CA15107
             Multi-Functional Nano-Carbon Composite Materials Network (MultiComp)

PROMES CNRS visit

Our team is visiting PROMES CNRS facilities (Font-Romeu, France). We are grateful for the access to the facilities in frame of SFERA 2 project. This great opportunity will be used to prepare samples for the successful realization of ERDF Project Nr.1.1.1.1/16/A/182.

IMG-20170724-WA0000

Granted access to MSSFs Facility at PROMES, CNRS

Our group was accepted to access PROMES CNRS solar facilities within the framework of the EU-DG RTD’s project: “The European Solar Research Infrastructure for Concentrated Solar Power. Second Phase – SFERA-II

We are looking forward to continue research collaboration with the facility and prepare samples for further study.

sfera logo

sfera reactor

ERDF project -Phosphorescent coatings prepared by plasma electrolytic oxidation-

     

Project No: Nr.1.1.1.1/16/A/182

Main scope:

The proposed project foresees studies of luminescent coatings prepared by plasma electrolytic oxidation (PEO). Up to now, PEO coatings were mostly studied because of their tribological properties; however, PEO coatings also have good wear resistance, high hardness and are chemically stable therefore this technology can be applied to form protective coatings on metals. It is known that many oxide based materials exhibit good luminescent properties; however, the luminescence of PEO produced oxide layers was not studied before. The first research in this direction was made by private company Elgoo tech in cooperation with Insitute of Solid State Physics University of Latvia.

During the research project, PEO process will be used to produce luminous aluminium coatings. The analysis of accessible data indicates that PEO synthesis is a promising approach for production of materials with long lasting luminescence, for example SrAl2O4:Eu:Dy. The coatings prepared by PEO will be transparent in blue and UV range, therefore the final long lasting luminescence efficiency is expected to be several times higher than that of luminescent paints currently in use. In addition, coatings could serve as protection for metals since the durability of such coatings is expected to be better compared to paints.

See information in Latvian here!

See official institute webpage about the project here!

UPDATES


A publication in Materials & Design presenting a novel method of phosphorescent strontium aluminate coating preparation on aluminum

We are proud to announce that a new publication “Novel method of phosphorescent strontium aluminate coating preparation on aluminum” has been written and published in Materials & Design in October. This publication was funded by the ERDF project “Phosphorescent coatings prepared by plasma electrolytic oxidation” No: Nr.1.1.1.1/16/A/182.

Novel method of phosphorescent strontium aluminate coating preparation on aluminum

Teksta latviskotā versija pieejama http://www.lum.lv/publikacija-par-jaunu-metodi-fosforiscejoso-parklajumu-izveidei-uz-aluminija-virsmas/

The search for defects in undoped SrAl2O4 material

A new publication in the frame of ERDF Project Nr.1.1.1.1/16/A/182 on fundamental processes in phosphorescent materials has been published.

Virginija Vitola, Donats Millers, Krisjanis Smits, Ivita Bite, Aleksejs Zolotarjovs

SrAl2O4:Eu,Dy is a very efficient long afterglow phosphor with wide range of possible applications. The luminescence properties and the possible luminescence mechanism of this material have been studied extensively, but there is almost no information available about the undoped material. Therefore, this article deals with the luminescence and thermally stimulated luminescence of an undoped SrAl2O4, revealing the possible defects that might be involved in the creation of the long afterglow in doped material. We conclude that undoped material exhibits some luminescence under X-ray irradiation in low temperature; close to room temperatures luminescence is almost fully thermally quenched in comparison to low temperatures. We can observe F and F2 center luminescence as wellas trace metal luminescence inthe emission spectrum.TSL glow curveyields the peaksthat are close to those observed in material with Eu and Dy doping; therefore these peaks are clearly related to intrinsic defects. The peak at around 400K, that is shifting with rare earth doping, might be due to dopant interaction with intrinsic defects.

Published in Optical Materials

Download PDF

Teksta latviskotā versija pieejama šeit: http://www.lum.lv/defektu-noteiksana-nedopeta-sral2o4-materiala/

ERAF projekts Nr.1.1.1.1/16/A/182 – Fosforiscējoša pārklājuma iegūšana plazmas elektrolītiskajā oksidācijas procesā – jaunumi

Pēdējo pāris mēnešu laikā panākts ievērojams uzlabojums procesa elektrisko parametru kontrolē,ko nodrošināja barošanas bloka veiktā modernizācija. PEO iekārtai ir vairāki uzlabojumi ieskaitot augstāku spriegumu limitu (līdz 1000 V), kā arī ar ievērojami vieglāk lietojamu programmatūru un automatizētiem vadības algoritmiem, kas ļauj nepārtraukti mainīt jebkuru vēlamo parametru procesa laikā. Šīs iespējas ļauj padziļināti izpētīt augsta sprieguma ietekmi uz pārklājuma veidošanas procesu un RE jonu ieviešanu tajā. Turklāt tika uzlabota barošanas avota stabilitāte, nodrošinot ilgāku nepārtrauktu apstrādes laiku pie lielām slodzēm. Tas ir svarīgi dažādiem oksīda fāzes veidošanās procesiem, jo pārkristalizācija notiek tikai ilgākos apstrādes laikos.
Tika sagatavots paraugu komplekts un turpināta parametru optimizācija. Galvenais mērķis ir nemainīgs: uzlabot ilgspīdošu PEO pārklājumu ar kvalitāti, kas sakrīt vai pārsniedz līdzīgu materiālu kvalitāti.

X-ray excited luminescence of SrAl2O4:Eu,Dy at low temperatures

A new publication in the frame of ERDF Project Nr.1.1.1.1/16/A/182 on fundamental processes in phosphorescent materials has been published.

V. Liepina, D. Millers * , K. Smits, A. Zolotarjovs, I. Bite

SrAl2O4:Eu,Dy is a very efficient long afterglow phosphor with wide range of possible applications. In this study we carried out the study of X-ray excited luminescence of SrAl2O4:Dy and SrAl2O4:Eu,Dy samples, including the measurements of afterglow at low temperatures within extended time scale. We observed both Eu and Dy luminescence peaks in the afterglow and TSL measurements. In recent articles the tunneling of electron from trap levels to excited Eu luminescence center was discussed, and in this research we conclude that under X-ray irradiation Eu2+ and Dy3+ serve as hole traps; electron tunneling is present in both SrAl2O4:Eu, Dy and SrAl2O4: Dy, and luminescence afterglow at 10 K arises from decay of excited Eu2+ and Dy3+ centers created via electron tunneling from host trap to Eu3+ and Dy4+ ions.

Journal of Physics and Chemistry of Solids

pdf-iconDownload PDF

Teksta latviskotā versija pieejama šeit: http://www.lum.lv/rentgenstarojuma-ierosinata-sral2o4-luminescence-zemas-temperaturas/

Project ERDF Project Nr.1.1.1.1/16/A/182: Phosphorescent coatings prepared by plasma electrolytic oxidation update

PEO A certain project milestone has been recently achieved and luminescent coatings with sufficient luminescence intensity to be seen by the naked eye have been acquired. We will continue our work on intensity and luminescence afterglow parameter improvement and it certainly looks like we’re moving in the right direction although of course there’s tons of work still ahead of us.

A publication studying optical properties of strontium aluminate has been submitted and is being reviewed.

We’re also happy to announce that starting September Boriss Poļakovs and Krišjānis Auziņš have joined the project and are actively working to contribute to project’s successful ongoing.

Improvements on PEO reactor chamber (see photo) have been  made to insure better repeatability and constant results, allowing to study the coatings with greater detail and less errors. Technical improvements have also been made to aluminum samples – it is now possible to split the samples into smaller pieces with absolutely no potential damage to the coating.

Teksta latviskotā versija pieejama šeit. 

 

PROMES CNRS visit

Our team is visiting PROMES CNRS facilities (Font-Romeu, France). We are grateful for the access to the facilities in frame of SFERA 2 project. This great opportunity will be used to prepare samples for the successful realization of ERDF Project Nr.1.1.1.1/16/A/182.

IMG-20170724-WA0000

ERAF projekts -Fosforiscējoša pārklājuma iegūšana plazmas elektrolītiskajā oksidācijas procesā-.

Līguma numurs 1.1.1.1/16/A/182

Projekta ilgums: 27.02.2017 -31.10.2019

Projekta zinātniskais vadītājs: Dr.phys. Krisjanis Smits

 

Projekta mērķis ir ne-saimnieciskajā rūpnieciskajā pētījumā iegūt alumīniju saturošu fosforiscējošu pārklājumu plazmas elektrolītiskās oksidācijas (PEO) procesā.

Projekta gaitā paredzēts PEO procesā iegūt leģētus ar Eu joniem aktivētus kompleksos oksīdus, izveidot aktivatoru nanokristālu pārklājumu poru aizpildīšanai un, veicot gala oksidāciju, PEO procesā iegūt luminiscentu pārklājumu. Paralēli veicamajām darbībām, tām tiks pielāgota SIA “ElGoo tech” īpašumā esošā PEO aparatūra un tās parametri, kā rezultātā iegūsim validētu nepatentētu tehnoloģiju. Tiks veikta iegūto materiālu īpašību (luminiscences, struktūras un morfoloģijas) izpēte. Plānots iepirkums, kura nolikumā, vērtēšanā un tehniskajā specifikācijā tiks piemēroti Zaļā publiskā iepirkuma kritēriji un principi.

Ar saimniecisko darbību nesaistīto projektu plānots īstenot kopā ar sadarbības partneri – komersantu SIA “ElGoo tech” no 2017.gada 1.februāra līdz 2019.gada 31.oktobrim, ar kuru kopā ir izstrādāts šis projekts un noslēgts sadarbības līgums. Plānotās projekta izmaksas ir 539 844.50 EUR.

Plānots iegūt 120 gab. fosforiscējoša pārklājuma paraugus, vienu šī procesa validētas nepatentētas tehnoloģijas aprakstu, 6 zinātniskos rakstus, piesaistīto privāto finansējumu un 1 komersantu, kurš sadarbojas ar pētniecības organizāciju. Pētījumā tiks nodarbināti vismaz 11 darbinieki, t.sk. 4, kuriem tiks izveidotas jaunas darba vietas.

Projektu plānots īstenot inovatīvo materiālu un tehnoloģijas nozarē izmantojot starpdisciplinaritāti – dabas zinātnes (1.3 fizika (Physical sciences) un 1.4 ķīmija (Chemical sciences)) un inženierzinātnes un tehnoloģija (2.5 materiālu zinātne (Materials engineering) un 2.10 nanotehnoliģijas (Nano-technology)).

Tiks pētīta iespēja izveidot luminiscentus pārklājumus, izmantojot plazmas elektroķīmisko oksidāciju (PEO). Patreiz PEO procesā iegūtie pārklājumi tiek aktīvi izmantoti, jo tiem piemīt labas aizsargājošās (liela cietība, laba nodilumizturība, termiskā aizsardzība, pretkorozijas uc.) īpašības. Metālu un dažu tā sakausējumu oksīdiem, ir labas optiskās īpašības, taču, piemēram, luminiscence PEO procesā iegūtiem pārklājumiem iepriekš nav pētīta. Pirmie pētījumi tika veikti SIA “ElGoo tech” sadarbojoties ar LU CFI, kuros iegūti pirmie labi luminiscējošie pārklājumi. Šie rezultāti un literatūrā atrodamie cita veida pētījumi parāda, ka ar PEO metodi iespējams izveidot arī fosforiscentos pārklājums, kuriem būtu ievērojams pielietojumu potenciāls, piemēram, SrAl2O4:Eu:Dy, kuram piemīt vienas no lielākajām kvantu efektivitātēm un ilgākā pēcspīdēšana.

Tādēļ šī pētījumu projekta ietvaros plānots iegūt alumīniju saturošus pārklājumus ar ilgu pēcspīdēšanu (fosforiscenci). Iegūstamie pārklājumi būs caurspīdīgi tuvajā UV apgabalā, tādejādi gala pārklājumam būs vairākas reizes lielāka efektivitāte salīdzinot ar pārdošanā esošajām fosforiscentajām krāsām. vienlaicīgi fosforiscējošais pārklājums kalpos kā metālu atikorozijas pārklājums un šāda pārklājuma noturība, ilgmūžība būs daudz lielāka salīdzinot ar krāsām.

Projekta sasniegtajiem rezultātiem pēc projekta beigām tiks nodrošināta:

  1. Finansiālā ilgtspēja – no valsts un privātā sektora budžeta tiks finansētas 4 jaunizveidotās darba vietas un finansēta projekta rezultātu publiskā pieejamība, SIA „ElGoo tech” no savas saimnieciskās darbības peļņas uzturēs projektā modificēto PEO aparatūru un budžetā paredzēs realizēt eksperimentālo pētījumu;
  2. Institucionālā ilgtspēja – 4 projektā iesaistītie zinātniskie darbinieki tiks nodarbināti jaunizveidotajās darba vietās, tā saglabājot pētījumā iegūto praktisko pieredzi un zinātību un izmantojot to tālākajā darbā, savukārt projekta īstenotāji (LU CFI un SIA „ElGoo tech”) apņemas pētījuma rezultātus izmantot savā turpmākajā zinātniskajā un saimnieciskajā darbībā;
  3. Politiskā ilgtspēja – ir nodrošināta, jo projekta mērķi atbilst RIS3 noteiktajiem tautsaimniecības transformācijas virzieniem un izaugsmes 1., 2. un 3.prioritātei. Projektu raksturojošie atslēgas vārdi – plazmas elektroķīmiskā oksidācija, pārklājumi, fosforiscence, luminiscence, oksīdi, nanokristāli.

 

Oficiālā www.CFI.lv lapa par projektu ir atrodama šeit.

Looking back. UPCON 2016: Bright future for upconversion

A great review of the may-2016 conference that took place in Wroclaw, Poland!

Check out the view from Dayong Jin published in Nature Photonics here.

upcon_image

Krisjanis Smits and Aleksejs Zolotarjovs had a really productive and interesting visit. We hope to meet again soon with all the participants of the conference.

European Cooperation in Science and Technology (COST) Action CM1403