@conference{
author = "Rajić, Vladimir and Ramadani, Barbara and Latas, Nemanja and Mančić, Lidija and Mantione, Daniele and Stanković, Ana and Ivanović, Milutin",
year = "2024",
abstract = "As the Sun is the most abundant energy source available, solar cells can become the primary source of renewable energy. Today, one of the most promising candidates to achieve this goal is perovskite solar cells (PSC) since they are solution-processable with PCE (>25%) that surpass conventional Si photovoltaics. However, the commercial potential of PSCs is still mainly limited by the low stability of perovskite active/absorbing layer to the environmental stimuli. This is also an issue in the case of formamidinium lead iodide perovskite - CH(NH2)2PbI 3 (FAPbI3 or FAPI) which possesses several advantages to be an active layer of efficient PSC, in comparison to the counterpart methylammonium lead iodide- CH3NH3PbI3 (MAPI). It has been shown that the humidity and oxygen from the atmosphere, heat, UV light and ion migration may have detrimental influences leading to the degradation of quality of material, and corollary performance and stability of the device. The reason for this vulnerability of perovskites is the complexity of the material itself, which is a multielement and multi-component hybrid material. To address the stability of perovskite thin films and the consequent performance of PSCs, various materials such as organic acids, metallic and organic halides, amines, organosulfur compounds, graphene, polymers, etc., have been proposed as additives or surface passivation agents. In this work, we opt for poly(ionic) (PILs) liquids additives, which are polyelectrolyte salts comprising cations and anions, with the cationic or anionic centers constrained to the repeating units in the polymer chain. PILs offer several advantages (even in comparison to their monomer counterparts), including high ionic conductivity, low vapor pressure, high hydrophobicity, excellent thermal and electrochemical stability, and a tunable chemical structure. Based on these qualities, PILs have found applications in various thin film electronic devices such as solar cells, light-emitting diodes, capacitors, etc. Aforementioned aspects make them also suitable candidates for controlling the growth of perovskite crystals, passivating grain boundaries and surface defects, improving interfacial energetics, doping the perovskite and hole transport material, and overall enhancing the stability and efficiency of PSCs. Furthermore, PILs based on TFSI pendant anion have shown potential for preparing compact grains of perovskites in thin films with less pronounced grain boundaries, significantly reducing the J-V hysteresis index in PSCs [1]. Also, the use of TFSI-based PILs has demonstrated efficient passivation of defects at the surface of perovskite thin films, which greatly reduces interface recombination and consequently improves device efficiency and stability for different perovskite compositions and architectures [2]. Hence within this work, two poly(ionic) liquids based on polymerized anion bis(trifluoromethane)sulfonamide (TFSI) (with pendant cations Li+ and imidazolium, namely [PLiMTFSI] Li and [PLiMTFSI] [DCMim]) are used as additives along with the counterpart salt LiTFSI. As could be seen in Fig 1. where XPS data are presented, after addition of [PLiMTFSI] [DCMim] the greatest shift towards lower binding energy was observed which is subscribed to the strongest p-doping/interaction of/with perovskite thin film found in this case. Furthermore, from UV-Vis absorption and Photoluminescence spectra of pristine perovskite thin film and with additives presented in Fig. 2 can be inferred that the highest intensity was measured in both type of spectra in the case of perovskite film with additive [PLiMTFSI] [DCMim]. Here is expected that PIL most effectively passivates defects at the surface and grain boundaries of perovskite polycrystalline thin film, which is reflected in better quality of the thin film and corollary higher absorption. Indeed, in Fig. 3 can be observed that after addition of PIL additives (in contrast to LiTFSI) [PLiMTFSI] Li and especially [PLiMTFSI] [DCMim] into the perovskite thin film, crystallites of perovskite grow bigger and the thin film becomes more homogeneous and uniform.",
publisher = "Belgrade : Serbian Academy of Sciences and Arts",
journal = "Program & Book of Abstracts / Third International Conference ELMINA 2024, Belgrade, Serbia, September 9th -13th, 2024",
title = "Influence of (Poly)ionic Liquid Additives on Electronic Structure, Optical Properties and Morphology of FAPbI3 Perovskite Thin Films for High Performance Solar Cells",
pages = "129-130",
url = "https://hdl.handle.net/21.15107/rcub_dais_16777"
}
