Project coordinator: Dr. Phys. Jurģis Grūbe

Total cost: 270 762 EUR

Duration (years): 2020-2022

LZP FLPP Nr. lzp-2019/1-0422

Preparation of active microstructures from photoresist/chromophore systems would benefit in cost-efficient device fabrication. Unfortunately, most organic chromophores absorb almost all of the blue light used for photolithography at the surface of the thin film and there is no light interaction with photoresist within the whole thin film. This drawback could be overcome by adding photoactive nanoparticles in photoresist exhibiting upconversion luminescence. Such nanoparticles absorb infrared light and emit blue light within the film.

The main goal of this project is development of photoresist/nanoparticle system that would be a part of the active media in organic photonic devices. Such approach opens new perspectives in creating organic waveguides and solid state lasers.

In the first part of the project issues related to synthesis of photoactive nanoparticles and mixing them into photoresist will be addressed. In the second part of the project photoresist doped with nanoparticles will be combined with organic chromophores. Photolithography of this complex system will be studied. In the end of project, we will assemble knowledge how nanoparticles are dispersed into photoresist and the possibility of combining with organic chromophores. Results of the project will give advanced knowledge required for the further development of organic laser.


Project news

04.07.2022.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Research and development on a modified nanoparticle synthesis method is ongoing. This may potentially reduce the cost of nanoparticle synthesis. Obtained nanoparticles do not possess spectroscopic properties suitable for the implementation of the project yet.
  2. Work continues on a new scientific article on a modified nanoparticle synthesis method.
  3. Work continues on the exposure of nanoparticles mixed into the photoresist. The repeatability of the production and exposure of samples allows the work on recording the structures to be elaborated further.
  4. The following samples are being prepared: nanoparticles, photoresist, organic compound, and photolithographic records are made in them.
  5. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. A focused laser diode beam with dimensions of around 20 µm has been obtained, which is sufficient to start creating various types of organic waveguides. In addition to the photolithography system, we have added a table, which can be precisely positioned in 2 dimensions in a controlled manner, allowing more complex structures to be recorded.
  6. We continue the work to prepare a publication of up-conversion luminescence photolithography
  7. Three students participated in the 18th International Young Scientist conference "Developments in Optics and Communications" 2022, April 21-22, 2022 in Riga, Latvia. They presented the conference participants with the scientific results obtained during the project in connection with the synthesis of nanoparticles and the incorporation of nanoparticles into SU8 photoresist, as well as the acquisition of structures using in a photolithography recording system created in the laboratory specific for this task. The conference took place online.

04.04.2022.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Research and development on a modified nanoparticle synthesis method is ongoing. This may potentially reduce the cost of nanoparticle synthesis.
  2. Work continues on a new scientific article on a modified nanoparticle synthesis method.
  3. Work continues on the exposure of nanoparticles mixed into the photoresist. The repeatability of the production and exposure of samples allows the work on recording the structures to be elaborated further.
  4. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. In addition to the photolithography system, we have added a table, which can be precisely positioned in 2 dimensions in a controlled manner, allowing more complex structures to be recorded.
  5. We continue the work to prepare a publication of up-conversion luminescence photolithography
  6. Two students participated in the 38TH SCIENTIFIC CONFERENCE AT THE INSTITUTE OF SOLID PHYSICS, UL, on February 22-24, 2022 in Riga, Latvia. They presented the scientific results obtained during the project related to the synthesis of nanoparticles, the incorporation of nanoparticles into SU8 photoresist, and the obtaining of structures. The conference took place online.

30.12.2021.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Research and development on a modified nanoparticle synthesis method is ongoing. This may potentially reduce the cost of nanoparticle synthesis.
  2. We have started to prepare a new scientific article on a modified nanoparticle synthesis method.
  3. Work continues on the exposure of nanoparticles mixed into the photoresist. The repeatability of the production and exposure of samples allows the work on recording the structures to be elaborated further.
  4. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. In addition to the photolithography system, we have added a table, which can be precisely positioned in 2 dimensions in a controlled manner, allowing more complex structures to be recorded.
  5. We continue the work to prepare a publication of up-conversion luminescence photolithography.
  6. Project coordinator Jurģis Grūbe has participated in the 4th International Conference on Optics, Photonics and Lasers (OPAL' 2021), October 13-15, 2021, Corfu, Greece.

30.09.2021.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Research and development on a modified nanoparticle synthesis method is ongoing. This may potentially reduce the cost of nanoparticle synthesis.
  2. Work continues on the exposure of nanoparticles mixed into the photoresist. Repeatability of sample production and exposure has been achieved. The exposed structures show a thickness of less than a micron.
  3. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. We were able to focus the laser diode beam on a spot less than 50 µm, which would allow to reduce the exposure time for the photoresist, and create finer exposed structures.
  4. A scientific article has been published: J. Grube, Up-Conversion Luminescence Processes in NaLaF4 Doped with Tm3+ and Yb3+ and Dependence on Tm3+ Concentration and Temperature, Applied Spectroscopy (2021), https://doi.org/10.1177/00037028211045424, which explains how temperature affects the intensities of up-conversion luminescence bands of Tm3+.

We have started to prepare a new scientific article.


30.06.2021.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. The process of synthesis of sore-shell nanoparticles has been continued. The core consists of NaYF4:Yb3+,Tm3+, and the shell is NaYF4. Electron microscopy measurements show that the size of synthesised sore-shell nanoparticles is less than 100. Intense up-converted luminescence in the UV spectrum was observed for the synthesised nanoparticles.
  2. While working on nanoparticle synthesis, the scientific group came up with ideas on how the nanoparticle synthesis method could be modified, which would potentially reduce the expenses of nanoparticle synthesis. Work continues to explore the potential of this method.
  3. Work continues on the exposure of nanoparticles mixed into the photoresist. Repeatability of sample production and exposure has been achieved. The exposed structures show a thickness of less than a micron.
  4. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. We were able to focus the laser diode beam on a spot less than 50 µm, which would allow to reduce the exposure time for the photoresist, and create finer exposed structures.

31.03.2021.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Core-shell nanoparticles have been successfully synthesised. The core consists of NaYF4:Yb3+, Tm3+, and the shell is NaYF4. Electron microscopy measurements show that the size of synthesised sore-shell nanoparticles is less than 100.
  2. Work continues on the exposure of nanoparticles mixed into the photoresist. The influence of preparation, exposure, and development parameters of various photoresists on the properties/stability of the exposed structures has been determined.
  3. Work continues to improve the experimental equipment for photolithography by focusing the laser diode beam with the help of a prism and a lens. We were able to focus the laser diode beam on a spot less than 50 µm, which would allow to reduce the exposure time for the photoresist, and create finer exposed structures.

30.12.2020.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. Work continues on the improving of the equipment for the synthesis of nanoparticles. The process of synthesis of sore-shell nanoparticles has been started. Growing a shell structure consisting of e.g. inactivated NaYF4 around the core nanoparticles allows to improve the spectroscopic properties of activated (core) nanoparticles.
  2. Several experiments have been performed with the exposure of nanoparticles mixed into the photoresist to determine the parameters that affect the exposure itself, and the subsequent development process.
  3. Work continues to improve the experimental equipment for photolithography by focusing the laser beam with the help of a prism and a lens.

30.09.2020.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. The work continues on improving the equipment for the synthesis of nanoparticles. The process of synthesis of sore-shell nanoparticles has been started. Growing a shell structure consisting of e.g. inactivated NaYF4 around the core nanoparticles allows to improve the spectroscopic properties of activated (core) nanoparticles.
  2. The work to improve the equipment for photolithography has been started. The system that is used currently is a to be upgraded by adding a more efficient laser diode beam focusing system so that the laser diode could be focused into a tighter spot.

30.06.2020.

The work continues in the shadow of the COVID-19 pandemic. We are facing various constraints that affect the project implementation.

  1. The work continues on improving the equipment for the synthesis of nanoparticles. The first synthesis processes have been performed. The obtained results allow to make improvements to the synthesis equipment so that the process runs smoothly, and high repeatability is achieved.
  2. The nanoparticles were mixed into a photoresist to create a composite material. UC photolithography is performed on this composite material at different exposure times. After development, it was observed that exposure has taken place, and structures have been created in the composite material. The obtained structures have been analysed (geometric dimensions) using an optical microscope, and a Dektak profilometer.

31.03.2020.

  1. The work to improve the equipment for the synthesis of nanoparticles has been started. Chemicals that are necessary for more successful implementation of the synthesis of nanoparticles have been purchased.
  2. Light absorption measurements have been performed on various photoresists (SU8, AZ1505, and others) to determine the positions of their absorption bands. They will later be compared with the up-converted luminescence spectra of the synthesised nanoparticles.
  3. The reaction of different photoresists to the mixing with different solvents in which the synthesised nanoparticles are intended to be stored is investigated.
  4. A COVID-19 pandemic has begun, that has limited work capacity in the laboratories. We are working remotely on analysing the scientific literature.