Photonics / Fotonik

Permanent URI for this collectionhttps://hdl.handle.net/11147/2590

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Author: search.filters.author.Ersan, FatihWoS Q: search.filters.wosQuartile.Q3

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Thickness-Dependent Piezoelecticity of Black Arsenic From Few-Layer To Monolayer
    (Elsevier, 2023) Akgenç Hanedar, Berna; Ersan, Fatih; Altalhi, Tariq; Yağmurcukardeş, Mehmet; Yakobson, Boris
    Ultra-thin forms of black phosphorus (b-P) have been widely investigated due to its unique properties arising from the in-plane anisotropy in its crystal structure. Recently, two-dimensional (2D) forms of black arsenic (b-As) have also been added to the 2D family. In this study, the thickness-dependent structural, electronic, and piezoelectric properties of layered b-As are investigated by means of ab-initio calculations. The structural optimizations confirm the van der Waals type layered structure for both these structures. In addition, increasing the thickness is shown to result in the decreasing of the band gap arising from the confinement of electrons in the layers. In contrast to the case of b-P, it is revealed that a transition from indirect-to-direct band gap behavior can be found in b-As which can be important for optically identifying the single-layer structure. Moreover, the piezoelectric properties are investigated as a function of the number of layers. It is shown that while a single-layer of b-As does not exhibit piezoelectric features, even in the case of bilayer structures the piezoelectricity is created. Our results revealed the strong in-plane anisotropy in piezoelectric coefficients for the three-layer and thicker structures. We have shown that the out-of-plane piezoelectric properties can be achieved by non-centrosymmetric features in the out-of-plane direction in thicker structures of b-As.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 23
    Aluminum and Lithium Sulfur Batteries: a Review of Recent Progress and Future Directions
    (IOP Publishing, 2021) Akgenç, Berna; Sarıkurt, Sevil; Yağmurcukardeş, Mehmet; Ersan, Fatih
    Advanced materials with various micro-/nanostructures have attracted plenty of attention for decades in energy storage devices such as rechargeable batteries (ion- or sulfur based batteries) and supercapacitors. To improve the electrochemical performance of batteries, it is uttermost important to develop advanced electrode materials. Moreover, the cathode material is also important that it restricts the efficiency and practical application of aluminum-ion batteries. Among the potential cathode materials, sulfur has become an important candidate material for aluminum-ion batteries cause of its considerable specific capacity. Two-dimensional materials are currently potential candidates as electrodes from lab-scale experiments to possible pragmatic theoretical studies. In this review, the fundamental principles, historical progress, latest developments, and major problems in Li-S and Al-S batteries are reviewed. Finally, future directions in terms of the experimental and theoretical applications have prospected.