Periodic Reporting for period 1 - BOLLA (Bandgap tunable perovskites for Organic poLLutAnts removal in water)
Okres sprawozdawczy: 2021-10-01 do 2023-09-30
The action BOLLA is a study of fundamental physics with strong technological relevance aimed at investigating new strategies to modulate the bandgap of metal halide perovskite (MHP) semiconductors, ensuring long term stability and efficiencies. The final objective of the project is to exploit such bandgap tunability to engineer a flexible solar driven electrochemical water purification system using only earth-abundant and inexpensive materials and fabrication methods that are compatible with large-scale large-volume production, encompassing several fields of chemistry, physics, materials science and engineering. Organic pollutants in water represent a serious concern because they cannot be efficiently eliminated in conventional wastewater systems. Electrochemical oxidation is a viable alternative approach which, however, requires high power inputs to drive the reactions. Solar energy could be used instead. Among the available new technologies in the photovoltaic sector, MHP semiconductors are by far the most promising, thanks to their tunable optoelectronic properties and high efficiency. In this sense, the possibility of tuning the semiconductor bandgap is a fundamental property to customize and target the right voltage to activate catalytic processes.
The main objectives of the project are: synthesizing photochemically and thermally stable MHP thin films, engineering printable carbon based MHP solar cells, designing an electrochemical system for the oxidation of organic pollutants in water and integrating the developed MHP solar cells with the working electrodes to drive the electrochemical reactions.
The main objectives of the project are: synthesizing photochemically and thermally stable MHP thin films, engineering printable carbon based MHP solar cells, designing an electrochemical system for the oxidation of organic pollutants in water and integrating the developed MHP solar cells with the working electrodes to drive the electrochemical reactions.
The work has been structured in 5 interconnected work packages (WPs): 4 scientific WPs, each one connected to a specific project’s objective, and an extra work package dedicated to dissemination and exploitation activities. The first work package focused on developing photochemically stable halide perovskite materials with both wide and narrow bandgaps. Narrow bandgap materials have been achieved by using Sn-based, fully iodide halide perovskite compositions, which are notoriously electronically p-doped semiconductors. We performed an in-depth study of their optoelectronic properties, highlighting the interplay between defects contributing to doping and the ones which instead act as non-radiative recombination channels. These results have been mainly included in 2 publications: Mater. Horiz., 2022,9, 1763-1773 and Adv. Sci. 2022, 2202795. Wide bandgap materials have been achieved through mixed halide I/Br Sn-based perovskite compositions. We showed for the first time that this class of materials do not suffer from photo-induced halide segregation and that a fine tuning of Br content can lead to films with reduced doping and improved optoelectronic quality. These results have been published in the following articles: ACS Energy Lett. 2023, 8, 6, 2801–2808 and ACS Energy Lett. 2023, 8, 9, 3876–3882.
The second work package focused on engineering fully printable carbon-based architectures for the fabrication of printable solar cells. Together with VTT in Oulu, Finland, which took part in the project BOLLA as Secondment organization, we were able to study the rheological properties of both commercial and home-made conductive pastes to optimize the printing quality and engineer solar cell devices consisting of a triple-mesoscopic stack where the perovskite active material gets infiltrated. The third work package looked at the characterization of the electrochemical system for the electrical oxidation of dyes in water, which are common organic pollutants. We used treated carbon paper sheets as electrodes and we optimized the voltage response of the system at different applied voltages, finding a maximum degradation rate at 1.4 V. Finally, in the last experimental work package, we designed photovoltaic devices to be coupled with the electrochemical system to perform photo driven oxidation of organic pollutants in water. We obtained 90% removal of organic dyes by using two carbon-based cells connected in series, with maximum power point voltage and current of 1.2 V and 19.5 mA, respectively.
BOLLA's results have been disseminated through conference presentations, journal publications and outreach activities. The Fellow presented her research at five different conferences throughout the duration of the Action where she contributed with 4 talks and 1 poster and 4 articles have been already published in peer-reviewed journals. Additional manuscripts that use data collected during this fellowship are currently under development. During the project she also organized a Conference Science Cafè as part of the Genoa Science Festival 2022.
The second work package focused on engineering fully printable carbon-based architectures for the fabrication of printable solar cells. Together with VTT in Oulu, Finland, which took part in the project BOLLA as Secondment organization, we were able to study the rheological properties of both commercial and home-made conductive pastes to optimize the printing quality and engineer solar cell devices consisting of a triple-mesoscopic stack where the perovskite active material gets infiltrated. The third work package looked at the characterization of the electrochemical system for the electrical oxidation of dyes in water, which are common organic pollutants. We used treated carbon paper sheets as electrodes and we optimized the voltage response of the system at different applied voltages, finding a maximum degradation rate at 1.4 V. Finally, in the last experimental work package, we designed photovoltaic devices to be coupled with the electrochemical system to perform photo driven oxidation of organic pollutants in water. We obtained 90% removal of organic dyes by using two carbon-based cells connected in series, with maximum power point voltage and current of 1.2 V and 19.5 mA, respectively.
BOLLA's results have been disseminated through conference presentations, journal publications and outreach activities. The Fellow presented her research at five different conferences throughout the duration of the Action where she contributed with 4 talks and 1 poster and 4 articles have been already published in peer-reviewed journals. Additional manuscripts that use data collected during this fellowship are currently under development. During the project she also organized a Conference Science Cafè as part of the Genoa Science Festival 2022.
BOLLA achieved many different breakthrough results. We showed for the first time that Sn based perovskites can be used to obtain both narrow and wide bandgap semiconductors, allowing for photostable bandgap tuning between 1.3 and 2.2 eV. We managed to obtain photochemically stable materials, where defects were investigated as primary source of instability. The defect activity in these materials is indeed very peculiar. Defects which contribute to electronic doping coexist with deep traps and finely tuning the chemical composition helps in shifting their equilibrium and prevalence. Finally, we coupled for the first time printable halide perovskite solar cells with carbon-based electrodes dipped in water to run photo driven oxidation of organic pollutants in water.
The output results of BOLLA far exceeded promises and results obtained during this fellowship will surely continue to achieve impact in coming years. On a wider scale, the activities of BOLLA hang together with the European Union’ efforts towards the implementation of the United Nations 2030 Agenda that includes the 17 Sustainable Development Goals. More specifically BOLLA well identifies with goals 6 and 7, which relate to Clean Water and Sanitation and Affordable and Clean Energy, respectively.
All details of the Action, the main scientific results and outreach activities can be found on the project website: https://bolla-msca.eu/(odnośnik otworzy się w nowym oknie).
The output results of BOLLA far exceeded promises and results obtained during this fellowship will surely continue to achieve impact in coming years. On a wider scale, the activities of BOLLA hang together with the European Union’ efforts towards the implementation of the United Nations 2030 Agenda that includes the 17 Sustainable Development Goals. More specifically BOLLA well identifies with goals 6 and 7, which relate to Clean Water and Sanitation and Affordable and Clean Energy, respectively.
All details of the Action, the main scientific results and outreach activities can be found on the project website: https://bolla-msca.eu/(odnośnik otworzy się w nowym oknie).