The Photochemical Stability of PbI2 and PbBr2: Optical and XPS and DFT Studies

We investigated the photochemical stability of PbX2 (X = I and Br) halides by optical and X-ray photoelectron spectroscopy (XPS). The optical absorbance displayed a strong reduction for PbI2 with light soaking and permanent behavior for PbBr2. The XPS survey spectra showed a sharp drop in the I:Pb ratio for PbI2 from 1.63 to 1.14 with exposure time from 0 to 1000 h while for PbBr2, it remains practically unchanged (1.59–1.55). The measurements of the XPS Pb 4f and Pb 5d spectra have shown the partial photolysis of PbI2 with the release of metallic lead whereas PbBr2 demonstrated remarkable photochemical stability. According to the density functional theory (DFT), calculations of the metal and iodide vacancy formation energies for PbBr2 are higher than for PbI2 which confirms the better stability to light soaking. The high photochemical stability of PbBr2 means that it can be used as excess under MAPbBr3 perovskite synthesis to improve not only the power conversion efficiency but also stability to light soaking. © 2023 by the authors.Russian Foundation for Basic Research, РФФИ: 21-52-52002; Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A18-118020190098-5, FEUZ-2023-0013; Fédération pour la Recherche sur le Cerveau, FRC: 0089-2019-0010/AAAA-A19-119071190044-3This work was supported by the Ministry of Science and Higher Education of the Russian Federation under the theme “Electron” No. AAAA-A18-118020190098-5 and Project FEUZ-2023-0013. The XPS measurements were supported by the Russian Foundation for Basic Research (Project No. 21-52-52002). Sample preparation was supported at FRC PCP MC RAS by the Ministry of Science and Higher Education of the Russian Federation (Project No. 0089-2019-0010/AAAA-A19-119071190044-3)

OBTAINING OF COMPLEX NANOPARTICLES BY THE SPARK DISCHARGE METHOD

In the research, several samples of complex oxide FeAl2O4 nanopowders and intermetal-lic FeAl nanopowders were obtained by the spark discharge method. X-ray diffraction anal-ysis and BET analysis, were performed and obtained dependence of electrode mass loss on input energy into discharge circuit

THE EFFECT OF A-CATION SUBSTITUTION ON THE STABILITY OF HYBRID PEROVSKITES UNDER POWERFUL ELECTRON FLUXES

Perovskites with A-cation substitution APbI3 (where A= MA, FA, Cs0.12FA0.88, Cs0.1MA0.15FA0.75) were studied by XRD analysis, XPS, UV-VIS, PL spectroscopy, AFM, SEM. Perovskites with A = Cs0.12FA0.88 and FA have shown remarkable stability under electron irradiation.Работа выполнена при поддержке гранта РНФ 22-61-00047

THE EFFECT OF PARTIAL LEAD SUBSTITUTION ON THE STABILITY OF HYBRID PEROVSKITES UNDER POWERFUL ELECTRON FLUXES

Perovskites with partial lead substitution CsFAMxPb1-xI3 (where M is various metals) were studied by XRD analysis, UV-VIS, PL spectroscopy, AFM, IR S-SNOM, SEM. Perovskites with M = La3+, Lu3+, Ag+ and Dy2+ have shown remarkable stability under electron irradiation.Работа выполнена при поддержке гранта РНФ 22-61-00047

USING EU2+/EU3+ REDOX CHEMISTRY TO BOOST PHOTOSTABILITY AND RADIATION HARDNESS OF PEROVSKITE

The work is devoted to the use of Eu[над]2[над]+/Eu[над]3[над]+ redox chemistry to increase the photostability and radiation resistance of complex lead halides (perovskites), as this will allow the use of perovskites as batteries for spacecraft and in solar cells on Earth conditions.Работа выполнена при поддержке РНФ (грант 22-61-00047)

TOWARDS BETTER PEROVSKITE ABSORBER MATERIALS: Cu+ DOPING IMPROVES RADIATION HARDNESS OF COMPLEX LEAD HALIDES

We present the possibility of controlling the electronic properties and major hybrid perovskites degradation pathways through minor modification of their chemical composition (e.g., replacing 1% of Pb2+ with Cu+) for engineering new perovskite absorber for aerospace applications.Работа выполнена при поддержке гранта РНФ 22-61-0047

MEASURING DISCHARGE ENERGY IN THE INSTALLATION OF NANOPARTICLES SYNTHESIS BY THE SPARK DISCHARGE METHOD

A new method of waveform processing that has not been used before is proposed in order to determine the electrode drop in voltage and energy introduced into the discharge gap. The method can serve as a useful complement to existing methods