Browsing by Author "Gordesli-Duatepe, Fatma Pinar"

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    Effect of Uv Light Exposure Duration on the Removal of Exfoliation Agent Residues in Two-Dimensional Perovskite Nanosheets: an Afm Study
    (John Wiley and Sons Inc, 2025) Gördesli Duatepe, Fatma Pınar; Küçükcan, Begümnur; Sağlam, Özge; Pinar Gordesli-Duatepe, Fatma; Gordesli-Duatepe, Fatma Pinar
    Accurate determination of dielectric properties and surface characteristics of two-dimensional (2D) perovskite nanosheets, produced by chemical exfoliation of layered perovskites, is often hindered by exfoliation agent residues such as tetrabutylammonium (TBA). This study investigated the effect of ultraviolet (UV) light exposure duration on the removal of TBA residues from 2D Ca2NaNb4O13− nanosheets deposited on silicon substrates via Langmuir-Blodgett method using atomic force microscopy (AFM). Nanoscale adhesion forces between silicon AFM tips and nanofilms exposed to UV light for 3, 12, 18, and 24 hours were measured. Nanofilms exposed to UV for 12 hours showed significant heterogeneity in adhesion forces compared to control nanofilms not exposed to UV. This heterogeneity improved after 18 hours and reached maximum homogeneity at 24 hours. A noticeable decrease in adhesion forces indicated a reduction in TBA residues after 18 hours, with further reduction observed at 24 hours. The most probable adhesion forces for control nanofilms and those exposed to UV for 3 and 12 hours were 1.6-fold and 2.0-fold higher, respectively, compared to nanofilms exposed to UV for 18 and 24 hours. Similarly, surface roughness peaked at 12 hours and then decreased with longer exposure, resulting in a smoother surface at 24 hours. © 2025 The Author(s). ChemPlusChem published by Wiley-VCH GmbH.
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    Langmuir-Blodgett Deposition and Physicochemical Surface Characterization of Two-Dimensional Perovskite Nanosheets on Ito-Pet Substrates
    (Elsevier B.V., 2023) Küçükcan B.; Günay B.; Gordesli-Duatepe F.P.; Sağlam Ö.; Sağlam, Özge; Gordesli-Duatepe, Fatma Pinar; Küçükcan, Begümnur; Günay, Bensu
    We successfully obtained Ca2NaNb4O13? single perovskite nanosheets by delaminating x = 4 Dion-Jacobson type KCa2NaNb4O13 layered materials. These nanosheets were then deposited onto conductive, transparent, and flexible indium tin oxide-polyethylene terephthalate (ITO-PET) substrates using the Langmuir-Blodgett (LB) technique. The polar and apolar (dispersive) surface tension components of LB nanofilms composed of Ca2NaNb4O13? perovskite nanosheets and the work of adhesion between the nanofilms and silicon and ITO-PET substrates were determined through contact angle measurements combined with mathematical modeling based on surface thermodynamics. The results showed that the apolar surface tension components had similar values for all surfaces studied, while the polar surface tension components of the nanofilms deposited on the substrates had higher values than those of the bare substrates. The higher polar interaction observed between the nanofilm and ITO-PET resulted in higher total work of adhesion of the nanofilm to the ITO-PET surface in water, while the total work of adhesion computed between the nanofilm and Si was higher in air. © 2023 Elsevier B.V.