Title:	Role of the Fabrication Technique in the Stability of CH3NH3PbI3 Perovskite Thin Films
Author(s):	M. Habibi, M. Eslamian
Topic:	Thin Film Photovoltaics
Subtopic:	Perovskite, Organic and Dye-Sensitised Devices
Event:	33rd European Photovoltaic Solar Energy Conference and Exhibition
Session:	3DV.2.108
Pages:	1213 - 1217
ISBN:	3-936338-47-7
Paper DOI:	10.4229/EUPVSEC20172017-3DV.2.108
Price:	0,00 EUR
Document(s):	paper, poster

Abstract/Summary:

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Despite the high power conversion efficiency of the state-of-the-art halide perovskite solar cells, their poor stability against humidity, oxygen, temperature, and light has hindered their commercialization. In this work, it is shown that the nature of the deposition method, and its attributes, is an important parameter that affects the stability of the perovskite films. To this end, the stability of the CH3NH3PbI3 perovskite films deposited by spray and blade coating, as two scalable and commercially viable techniques, and spin coating, as a lab scale technique are compared. To achieve a uniform and defect-free film made by spray and blade coating, the substrate temperature was raised during the deposition process, whereas the anti-solvent treatment was performed in the case of the spin-coated films. It is shown that the perovskite stability is influenced by the morphology of the film which is in turn controlled by the dynamics of the coating process. The stability analysis was performed by obtaining the SEM and XRD graphs of the films exposed to a humid environment (35-60%). Comparison of the ratio of the XRD peak intensity of the lead iodide (PbI2) to perovskite after 10 days revealed that the blade-coated samples are the most stable films. The sprayand spin- coated counterparts, on the other hand, are rough and prone to decomposition. It is also observed that the fabrication of a fully-covered and smooth perovskite film through the anti-solvent engineering can prolong the stability of the spin-coated films. In conclusion, a smooth film with fewer number of gap-free grain boundaries is found to be more stable. In this context, the blade-coated samples and then the spin-coated samples treated by antisolvent (toluene) showed the best stability.