Understanding the Mechanisms of Methylammonium-Induced Thermal Instability in Mixed-FAMA Perovskites.

Autor: Tay DJJ; Interdisciplinary Graduate Programme (IGP), Graduate College, Nanyang Technological University, Singapore, 637460, Singapore.; Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, Singapore, 637553, Singapore., Febriansyah B; School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore., Salim T; School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore., Kovalev M; Cambridge Centre for Advanced Research and Education (CARES), 1 Create Way, Singapore, 138602, Singapore., Sharma A; School of Electrical and Electronics Engineering, Nanyang Technological University, Singapore, 639798, Singapore., Koh TM; Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, Singapore, 637553, Singapore., Mhaisalkar SG; Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, Singapore, 637553, Singapore.; School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore., Ager JW; Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, 94720, USA., Mathews N; Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, Singapore, 637553, Singapore.; School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Aug 08, pp. e2403389. Date of Electronic Publication: 2024 Aug 08.
DOI: 10.1002/smll.202403389
Abstrakt: Despite a recent shift toward methylammonium (MA)-free lead-halide perovskites for perovskite solar cells, high-efficiency formamidinium lead iodide (FAPbI 3 ) devices still often require methylammonium chloride (MACl) as an additive, which evaporates away during the annealing process. In this article, it is shown that the residual MA + , however, triggers thermal instability. To investigate the possibility of an optimal concentration of MA + that may improve thermal stability, the intrinsic thermal stability of pure FA, FA-rich, MA-rich, and pure MA perovskite films (FA 1-x MA x PbI 3 , FAMA) is studied. The results show that the thermal stability of FAMA perovskites decreases with more MA + , under degradation conditions that isolate the intrinsic thermal stability of the material (i.e., without moisture and oxygen effects). X-ray diffraction (XRD), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS), photoluminescence (PL) and UV-visible spectroscopy, and depth-profiling X-ray Photoelectron Spectroscopy (XPS) are employed to show that the observed trend is mainly due to the decomposition of the MA + cation, as opposed to other effects such as the precursor solvent and film morphologies. It is also found that the surfaces of these FAMA films are MA + rich, although this phenomenon does not appear to affect thermal stability. Finally, it is demonstrated that this trend is unaffected by the presence of Spiro-OMeTAD atop the film, and thus solar cell devices should preserve this trend.
(© 2024 Wiley‐VCH GmbH.)
Databáze: MEDLINE
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