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Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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Author: search.filters.author.Hernandez-Martinez, Pedro LudwigPublication Index: search.filters.publicationIndex.PubMed

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Tailored Synthesis of Iron Oxide Nanocrystals for Formation of Cuboid Mesocrystals
    (Amer Chemical Soc, 2021-08-02) Soran-Erdem, Zeliha; Sharma, Vijay Kumar; Hernandez-Martinez, Pedro Ludwig; Demir, Hilmi Volkan
    In this work, we systematically studied the shape- and size-controlled monodisperse synthesis of iron oxide nanocrystals (IONCs) for their use as building blocks in the formation of mesocrystals. For this aim, on understanding the influence of the oleic acid concentration, iron-oleate concentration, and heating rate on the synthesis of robust and reproducible IONCs with desired sizes and shapes, we synthesized highly monodisperse similar to 11 nm sized nanocubes and nanospheres. Magnetic measurements of both cubic and spherical IONCs revealed the presence of mixed paramagnetic and superparamagnetic phases in these nanocrystals. Moreover, we observed that the magnetic moments of the nanocubes are more substantial compared to their spherical counterparts. We then demonstrated a simple magnetic-field-assisted assembly of nanocubes into three-dimensional (3D) cuboid mesocrystals while nanospheres did not form any mesocrystals. These findings indicate that small cubic nanocrystals hold great promise as potential building blocks of 3D magnetic hierarchical structures with their superior magnetic properties and mesocrystal assembly capability, which may have high relevance in various fields ranging from high-density data storage to biomedical applications.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 14
    Near-Field Energy Transfer Into Silicon Inversely Proportional to Distance Using Quasi-2D Colloidal Quantum Well Donors
    (Wiley-VCH Verlag GmbH, 2021-09-12) Humayun, Muhammad Hamza; Hernandez-Martinez, Pedro Ludwig; Gheshlaghi, Negar; Erdem, Onur; Altintas, Yemliha; Shabani, Farzan; Demir, Hilmi Volkan
    Silicon is the most prevalent material system for light-harvesting applications; however, its inherent indirect bandgap and consequent weak absorption limits its potential in optoelectronics. This paper proposes to address this limitation by combining the sensitization of silicon with extraordinarily large absorption cross sections of quasi-2D colloidal quantum well nanoplatelets (NPLs) and to demonstrate excitation transfer from these NPLs to bulk silicon. Here, the distance dependency, d, of the resulting Forster resonant energy transfer from the NPL monolayer into a silicon substrate is systematically studied by tuning the thickness of a spacer layer (of Al2O3) in between them (varied from 1 to 50 nm in thickness). A slowly varying distance dependence of d(-1) with 25% efficiency at a donor-acceptor distance of 20 nm is observed. These results are corroborated with full electromagnetic solutions, which show that the inverse distance relationship emanates from the delocalized electric field intensity across both the NPL layer and the silicon because of the excitation of strong in-plane dipoles in the NPL monolayer. These findings pave the way for using colloidal NPLs as strong light-harvesting donors in combination with crystalline silicon as an acceptor medium for application in photovoltaic devices and other optoelectronic platforms.