Type: Specific Objective 1.1.1 "Improve research and innovation capacity and the ability of Latvian research institutions to attract external funding, by investing in human capital and infrastructure". measure “Industry-Driven Research”

Agreement No:

Duration: 2021. – 2023.

Project Leader: Institute of Solid State Physics, University of Latvia, Dr. habil. Phys. Donats Millers.

Project partners: Sidrabe Vacuum, Ltd; B.A.Sc. Matiss Piesins.

Total budget: 535 856,88 EUR

ISSP UL budget: 321 132.63 EUR

Project description:

The main goal of the project is the development of mechanoluminescent (ML) thin films for optical real time stress detectors. Such detector can be used in various applications connected to registration of stress anomalies, for example, dynamic stress sensing for diagnosis of possible damage in constructions via structural health monitoring process. Thin film coating is a material-efficient method where a thin layer of material can be deposited directly on the material of interest or be deposited on a polymer sheet or bulk material. The main result of the project is development of laboratory technology of applicable ML material.

The tasks of ISSP UL:

Elaborate technology of ML material synthesis as well as synthesis of ZnS:Mn and SrAl2O4: Eu, Dy, Cr  and other compositions. The study of ML mechanism, including impact of dopands, intrinsic defects and treatment of material. Investigations of luminescence intensity dependence on mechanical strain applied followed by choose of optimal composition for mechanical strain changes detection.  The study of thin films luminescent properties including mechanoluminescence and analysis of results obtained to assess possible applications for mechanical strain detection.


Progress of project implementation during 01.09.2023 – 13.10.2023


A Latvian patent for a mechanoluminescence detection device has been submitted. All the results obtained during the project are summarized, opportunities for future research are evaluated and the most promising directions in mechanoluminescence research are selected.

Progress of project implementation during 01.08.2023 – 30.08.2023


Observation of mechanoluminescence from composite materials (strontium aluminate particles embedded in epoxy) is used to further investigate the mechanism and electronic processes that cause this effect. Special attention is paid to the temperature dependence of mechanoluminescence.

The development of the Latvian patent for the mechanoluminescence detection device continues.

Progress of project implementation during 01.07.2023 – 31.07.2023


A Latvian patent for a mechanoluminescence detection device is being prepared, which is developed taking into account the obtained information on the specifics of mechanoluminescence measurements. At the same time, attempts to make a mechanoluminescent coating using the magnetron sputtering method continue. In addition, fundamental mechanoluminescence properties are investigated using powders, ceramics and composite materials.

Progress of project implementation during 01.04.2023 – 30.06.2023


Sample synthesis and mechanoluminescnece analysis is ongoing. At this stage, special attention is paid to coating methods that can be easily adapted to the production of existing parts (including 3D printing and modern composite material forming techniques). A large amount of time is also spent on prototyping tasks - the first iterations of the prototype have been created, with which it is possible to detect the signal of mechanoluminescent coatings. Peculiarities of using the prototype were also discussed - the ability of the portable device to analyze data locally with specially developed algorithms.

Progress of project implementation during 01.01.2023 – 31.13.2023


During this project stage, several samples were developed using different coating techniques and types. Not only magnetron sputtered coatings are investigated, but also the use of commercially available long-lasting powders in the creation of composite materials with the possibility of easily applying them to already created structures and parts is analyzed. In addition, the analysis of the experimental data was carried out to study the mechanism of mechanoluminescence with the aim of converting the signal from the optical sensor into a usable format.

Progress of project implementation during 01.10.2022 – 31.12.2022


The production of mechanoluminescent coatings using magnetron sputtering is proven to be non-trivial, with a row of challenges like the production of desired phase of complex oxide, getting large enough thickness without sacrificing the adhesion properties that are crucial for mechanoluminescence applications and getting luminescent properties good enough to be detectable with conventional methods. The team is creating series of samples using different oxides, dopants and sputtering parameters to achieve the desired performance. In parallel, other ways to develop mechanoluminescent coatings are under investigation –in fields of SLA 3d printing and incorporation in epoxy resin or paints for application on virtually any part.


Progress of project implementation during 01.07.2022 – 30.09.2022


During this stage of the project the continuation on investigation of mechanoluminescence properties of strontium aluminate coatings and powders was performed. In previous stages, the mechanoluminescence use in combination with additive manufacturing was demonstrated, with promising results in both usecases and performance of the approach. An additional publicaition on data analysis algorithms was developed for spatial stress distribution detection using convenvtional CMOS cameras, thus enabling the approach to be used in real scenarios independent of the type of coating – magnetron sputtered or epoxy/laque type.


Progress of project implementation during 01.04.2022 – 30.06.2022


During the research period from 01.04.2022. to 30.06.2022 of the project No. / 20 / A / 138 “Development of mechanoluminescent thin films for real-time stress detectors”, at ISSP UL the coatings received from the project partner Sidrabe were studied. Various optica, morphology and mechanical properties were analysed for coatings prepared with Eu and Dy dopants. The coatings were also prepared on various substrates. In addition, the addition of mechanoluminescent particle addition in polymers was studied, together with the evaluation of other coating production methods. During this period, the publication on Eu and Dy doped strontium aluminate nanoparticle use for spatial visualisation of mechanical stresses in 3d-printed parts was prepared. 


Progress of project implementation during 01.01.2022 – 31.03.2022


The magnetron sputtered layers and composite layers for mechanoluminescence investigation were prepared. The luminescence spectra, crystalline structure and composition of prepared layers were studied. It was found the composite layers containing SrAl2O4:Eu,Dy revealed the well expressed mechanoluminescent properties.

Results obtained in experiments were used in 2 presentations at ISSP, LU 2022 annual Scientific Conference (A. Spustaka and E.Einbergs), as well as at International Conference “Open Readings 2022” (A. Spustaka).


Progress of project implementation during 01.10.2021 – 30.12.2021


The study of ZnS:Mn thin films sputtering process optimization was continued. The optimal adhesion between film and Al substrate was obtained. It was observed that the thin films used in experiments have not well expressed crystalline structure and it could be the origin of luminescence difference of target material and thin film obtained from it. The experiments are foreseen for polycrystalline thin films obtaining.

The results and knowledge obtained during project implementation was presented by doctoral student Ernests Einbergs at the Latvian Scientific Council, Ministry of Education and Science and State Agency of Education and Development jointly organized action “Connect to Science”.


Progress of project implementation during 01.07.2021 – 30.09.2021


The studies of structure and luminescent properties of manganic doped zinc sulphide were completed for thin films.  The results of investigation of thin films first set (11 samples) was negotiated with partner Sidrabe Vacuum, Ltd and resulted in modification of thin films manufacturing technology. Therefore, more appropriate thin films were obtained and study of them is in progress.

The presentation for action of science popularization “Connect to Science” is under preparation. This action is jointly organized by the Latvian Scientific Council, Ministry of Education and Science and State Agency of Education and Development and will be hold within 04. October –  04. November, 2021.


Progress of project implementation during 01.04.2021 – 30.06.2021


The equipment for mechanoluminescence studies has been developed and tested. The 3 separate binders were tested for mechanoluminescent composition SrAl2O4:Eu,Dy  binding to material foreseen for mechanical deformation.

 A price survey has been conducted and followed by obtaining materials for thin film production on metallic Al substrate. These thin films are necessary for thin films mechanoluminescence testing.

Three students involved in the implementation of the project have improved their qualifications - replaced by a bachelor's degree, master's degree and doctoral degree. A presentation for a scientific conference is under preparation and therefore analysis is performed of information obtained in experiments.