| Is Part of |
Open readings 2023: 66th international conference for students of physics and natural sciences, April 18-21, 2023, Vilnius, Lithuania: annual abstract book / editors: M. Keršys, Š. Mickus.. Vilnius : Vilnius University press, 2023. p. 162.. ISBN 9786090708835 |
| Abstract [eng] |
For the last decade, perovskite solar cell technology gained significant popularity due to the promise of low-cost fabrication and high efficiency. On the way to successful commercialization, each component needs to be optimized, independent, and in full stack. In particular, hole-selective contact is commonly mentioned as one of the weaker links. And this is the case where molecular design can be particularly useful. In the last years, material [2-(9H-Carbazol-9-yl)ethyl]phosphonic acid, better known as 2PACz became a popular choice for the fabrication of perovskite solar cells. Originally used in tandem devices,[1] due to the simplicity of the layer formation, very low material consumption, and superior performance, this and related materials (MeO-2PACz and Me-4PACz) are becoming a “standard” option. Layer formation of the 2PACz is based on the (self)-assembly of the phosphonic acid functional group on the surface of indium tin oxide (ITO), thus leading to the functional layer with the thickness of the single molecule. 2PACz molecule has a T-shape, where the phosphonic acid functional group and linker are perpendicular to the carbazole molecule (attached to the nitrogen atom). In this work, we are exploring an alternative design, in which carbazole chromophore would be in the same line as the linker and anchoring group, proposedly having a “rod” – type shape. It is expected that this could lead to denser packing, avoiding “voids” between the molecules. As a consequence, due to the higher concentration of the carbazole chromophore higher efficiency and stability are anticipated. To achieve that, we are using the reactive -OH group in the second position of the carbazole for further functionalization. Starting with the 2-methoxy-9-methylcarbazole, the methoxy group was hydrolyzed with BBr3, and further functionalized with a phosphonic acid group through the three-stage synthesis, including alkylation, Arbuzov reaction, and nucleophilic ester cleavage. The structure of the target material was confirmed by means of 1H and 13C NMR spectroscopy. Synthesized materials will be further used for the fabrications of the perovskite solar cells and the performance will be compared to that of the state-of-the-art phosphonic acid-based selective materials. |
