Title: Development of tandem chalcogenide- organic solar cells
Research proposal No: 1.1.1.9/LZP/1/24/017
Duration: 01.04.2025.-31.03.2028.
Project Leader: Dr.phys. Raitis Gržibovskis
Total budget: 184 140 EUR
European Regional Development Fund (ERDF) funding: 156 519 EUR
ISSP UL budget: 9 207 EUR
Project description:
The European Union's goal of achieving CO2 neutrality by 2050 forces us to look for new and more environmentally friendly energy sources. One of these types is solar energy, which can be directly converted into electricity by solar cells. Today, a very relevant research direction is the use of organic materials in the creation of solar cells. The diversity of molecules and the possibility of creating flexible, lightweight, and semi-transparent solar cells make organic materials an attractive alternative to classic silicon solar panels.
However, organic materials have a drawback- a relatively short lifespan of solar cells made from them. While the effects of oxygen and moisture can be prevented by applying protective layers, it is more difficult to avoid degradation caused by light intensity and elevated temperatures. As a solution, this project proposes to create hybrid (chalcogenide-organic material) tandem solar cells. A solar cell based on antimony sulfide (Sb2S3) would absorb part of the sunlight, thereby reducing the amount of energy that reaches the organic materials. In this way, the lifespan of the solar cell could be extended.
The project aims to develop chalcogenide-organic tandem solar cells. It is planned that the chalcogenide layer will reduce the amount of light reaching the organic layer, thus extending the longevity of the tandem cell.
The work in the project will be divided into two stages. In the first stage, each (Sb2S3 and organic material) solar cell would be developed separately and they would be connected only electrically. In the second stage, a layered tandem solar cell would be created, where all layers would be physically on top of each other. Research related to Sb2S3 will be conducted at Tallinn University of Technology in Estonia, allowing the postdoctorate to gain new knowledge and skills in working with chalcogenides, their thin film deposition, and structure characterization. A work related to organic materials will be conducted at the Organic Materials Laboratory of the Institute of Solid State Physics of the University of Latvia.
PROJECT PROGRESS
Time period: 01.04.2025. - 31.08.2025.
At the beginning of the project, I visited our collaboration partners- Tallinn University of Technology (TalTech)- where the first experiments took place in the Laboratory for Thin Film Energy Materials, Department of Materials and Environmental Technology, led by tenured full professor Ilona Oja Acik. In the week and a half, I learned how to manufacture antimony sulfide (Sb2S3) solar cells by the spray pyrolysis method and how to characterize them by the equipment available at TalTech. The characterization included the measurements of current-voltage characteristics (I-V curves), the external quantum efficiency (EQE) measurements, as well as light absorption and transmittance measurements. A series of Sb2S3 solar cells was made with various active layer thicknesses.
Upon returning to the Institute of Solid State Physics, University of Latvia (ISSP UL), the Sb2S3 solar cells were used as the optical filters for organic solar cells (OSC). This allowed determining the optimal Sb2S3 solar cell manufacturing parameters were the efficiency of chalocogenide cells exceeded the losses in OSCs.
In August, we started the synthesis and characterization of NiOx nanoparticles, which could allow creating inverted Sb2S3 solar cells with the structure of ITO/ NiOx/ Sb2S3 / electron transport layer/ Ag.
I’ve submitted an abstract, “THE DEVELOPMENT OF 4T CHALCOGENIDE-ORGANIC TANDEM SOLAR CELLS” to participate in the 17th European Conference on Molecular Electronics (ECME 2025), which will take place in Cambridge, UK, from 22nd to 26th September 2025.
At the beginning of September, I’ve planned one more visit to TalTech.