Identification number: lzp-2022/1-0494
Type: Latvian Council of Science
Project duration: 2023 - 2025
Project manager: Dr.phys. Raitis Gržibovskis LU CFI
Partners: RTU, Faculty of Material Sciences and Applied Chemistry, Dr. chem. Kaspars Traskovskis
Total funding: 300 000 EUR
Project aim: The objective of this research project is the development of novel non-fullerene electron acceptors with one-dimensional charge transfer properties that will allow the construction of highly efficient ternary OSCs.
Project summary:
Solar cells allow turning the sunlight directly into electricity. While most of the commercially available solar cells are made of silicon, organic materials are actively researched. The most popular structure for organic solar cells (OSCs) is a bulk heterojunction layer consisting of donor and acceptor materials sandwiched between charge carrier transport layers and electrodes. The creation of bulk heterojunction cells leads to the trade-off principle: using narrow bandgap materials allows absorbing lower energy photons generating more current, but at the same time it leads to the voltage losses of the cell. One possible solution is an implementation of a tandem solar cell where two separate cells are working in different spectral regions. Yet, the multilayered structures greatly complicate the manufacturing process, making such devices less attractive for possible commercialization. A much simpler option is the use of ternary OSCs where the active layer consists of three materials instead of just two.
For several years the fullerenes were a popular group of acceptors for OSCs due to their solubility in organic solvents, high electron mobility, as well as their relatively deep electron affinity level. Unfortunately fullerenes also possess disadvantages which limit their use for OSCs: weak absorption, limited tunability of their energy levels, and morphological instability
In order to expand the spectral coverage and thus increase the attainable efficiency of the current generation of OSCs, in the proposed project we will develop novel ternary devices that will incorporate the known donor PBDB-T or its structural analogs and Y6 acceptor. This leaves a window of relatively weak absorbance in the 650-800 nm range, which will be covered by our-synthesized novel non-fullerene acceptors.