| Autor: |
Filipoiu N; Horia Hulubei National Institute for Physics and Nuclear Engineering, 077126, Magurele, Ilfov, Romania.; University of Bucharest, Faculty of Physics, 077125, Magurele, Ilfov, Romania. nemnes@solid.fizica.unibuc.ro., Mirea AG; National Institute of Materials Physics, Magurele, 077125, Ilfov, Romania. mihaela.florea@infim.ro., Derbali S; National Institute of Materials Physics, Magurele, 077125, Ilfov, Romania. mihaela.florea@infim.ro., Pantis-Simut CA; Horia Hulubei National Institute for Physics and Nuclear Engineering, 077126, Magurele, Ilfov, Romania.; University of Bucharest, Faculty of Physics, 077125, Magurele, Ilfov, Romania. nemnes@solid.fizica.unibuc.ro.; Research Institute of the University of Bucharest (ICUB), 90 Panduri Street, 050663, Bucharest, Romania., Anghel DV; Horia Hulubei National Institute for Physics and Nuclear Engineering, 077126, Magurele, Ilfov, Romania.; University of Bucharest, Faculty of Physics, 077125, Magurele, Ilfov, Romania. nemnes@solid.fizica.unibuc.ro.; Research Institute of the University of Bucharest (ICUB), 90 Panduri Street, 050663, Bucharest, Romania., Manolescu A; Department of Engineering, School of Technology, Reykjavik University, Menntavegur 1, IS-102, Reykjavik, Iceland., Pintilie I; National Institute of Materials Physics, Magurele, 077125, Ilfov, Romania. mihaela.florea@infim.ro., Florea M; National Institute of Materials Physics, Magurele, 077125, Ilfov, Romania. mihaela.florea@infim.ro., Nemnes GA; Horia Hulubei National Institute for Physics and Nuclear Engineering, 077126, Magurele, Ilfov, Romania.; University of Bucharest, Faculty of Physics, 077125, Magurele, Ilfov, Romania. nemnes@solid.fizica.unibuc.ro.; Research Institute of the University of Bucharest (ICUB), 90 Panduri Street, 050663, Bucharest, Romania. |
| Abstrakt: |
Electronic and stability properties of quasi-2D alkylammonium perovskites are investigated using density functional theory (DFT) calculations and validated experimentally on selected classes of compounds. Our analysis is focused on perovskite structures of formula (A) 2 (A') n -1 Pb n X 3 n +1 , with large cations A = butyl-, pentyl-, hexylammonium (BA, PA, HXA), small cations A' = methylammonium, formamidinium, ethylammonium, guanidinium (MA, FA, EA, GA) and halogens X = I, Br, Cl. The role of the halogen ions is outlined for the band structure, stability and defect formation energies. Two opposing trends are found for the absorption efficiency versus stability, the latter being assessed with respect to possible degradation mechanisms. Experimental validation is performed on quasi-2D perovskites based on pentylammonium cations, namely: (PA) 2 PbX 4 and (PA) 2 (MA)Pb 2 X 7 , synthesized by antisolvent-assisted vapor crystallization. Structural and optical analysis are inline with the DFT based calculations. In addition, the thermogravimetric analysis shows an enhanced stability of bromide and chloride based compounds, in agreement with the theoretical predictions. |
