Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Selective Growth of Fapbbr3 Nanocrystals With Precisely Tailored Optical Properties for Advanced Optoelectronic Applications(Amer Chemical Soc, 2025) Guvenc, C. Meric; Polat, Nahit; Arica, Tugce A.; Balci, SinanUnderstanding the evolution of semiconductor nanocrystals (NCs) during their colloidal synthesis is essential for achieving improved control over their physical and chemical properties. The fast reaction kinetics and concurrent nucleation and growth periods of lead halide perovskite NCs pose significant challenges in controlling the synthesis. Here, we present the room-temperature colloidal synthesis of FAPbBr3 NCs with physically decoupled nucleation and growth periods by using the common oleylamine and oleic acid ligand pair for lead halide perovskite NCs. Importantly, in this method, the nucleation and growth phases are entirely decoupled by halting the reaction at a metastable state, where the FAPbBr3 nuclei are formed. Subsequently, preformed FAPbBr3 nuclei are selectively grown by increasing supersaturation. This is achieved by reducing the monomer solubility through the injection of oleic acid into the solution. Notably, two-dimensional perovskite nanostructures form as intermediate products during the synthesis. Furthermore, the size of the FAPbBr3 NCs is tuned from 5.7 to 13.5 nm by controlling the injected oleic acid amount. Photoluminescence quantum yields of the FAPbBr3 perovskite NCs synthesized by using this method reached up to 95%. These findings demonstrate a robust strategy for the controlled synthesis of FAPbBr3 perovskite NCs, providing precisely tailored optical properties for advanced applications such as solar cells, photodetectors, and light-emitting diodes.Article Citation - WoS: 5Citation - Scopus: 5Light-Induced, Liquid Crystal-Templated Fabrication of Large-Area Pure Nanoporous Gold Films With High-Density Plasmonic Cavities(Amer Chemical Soc, 2024) Orhan, Ozan Baran; Polat, Nahit; Demir, Seren; Balci, Fadime Mert; Balci, SinanNanoporous gold (NPG) films are three-dimensional gold (Au) frameworks characterized by a uniform distribution of nanoscale irregular pores. Typically produced via a dealloying process, where the less noble silver (Ag) is selectively etched out, NPG films offer a large surface area, excellent chemical stability, remarkable catalytic activity, unique optical properties, and biocompatibility. These attributes make them invaluable for applications in catalysis, plasmonics, biosensors, and nanophotonics. However, the presence of residual Ag from the dealloying process can limit their performance in certain applications. In this study, we report a novel method for the fabrication of ultrapure, large-area NPG films (several cm2) using a light-induced and liquid crystal-templated method. A hexagonal lyotropic liquid crystal containing a strong acid and a nonionic surfactant is combined with an aqueous solution of HAuCl4, followed by the photochemical synthesis of gold nanoparticles (NPs) within the liquid crystal. After calcination of the Au NP-containing liquid crystal film at high temperature, pure NPG films are produced. We demonstrate surface-enhanced Raman spectroscopy (SERS) of Rhodamine 6G (R6G) molecules adsorbed on the NPG films and detect extremely low concentrations (below 10-6 M) of R6G. Additionally, we thoroughly investigated the formation and optical properties of the NPG films. The results reveal that the ultrapure NPG films contain high-density plasmonic nanocavities, where substantial electromagnetic fields are generated, leading to significant enhancement of optical processes at nanoscale dimensions.Article Citation - WoS: 1Citation - Scopus: 1Hyperspectral Imaging of Exciton Polaritons in Optical Microcavities(Amer Chemical Soc, 2024) Polat, Nahit; Yakar, Ozan; O''zdemir, Sahin K.; Balci, SinanPhotons can be confined in optical microcavities both spectrally and spatially, which allows us to study the light-matter interaction in both weak and strong coupling regimes. While the former is identified by the Purcell factor, which quantifies the suppression or enhancement of the spontaneous emission rate of the quantum emitters coupled to the cavity modes, the latter is identified by the formation of hybrid photon-matter modes called exciton polaritons and thus represents an avoided crossing in the spectra. Until now, various imaging and spectroscopic techniques have been extensively used to study exciton polariton formation in optical microcavities, and the coupling between excitons and photons has been statically and dynamically tuned. Herein, we demonstrate the hyperspectral imaging of exciton polaritons in optical microcavities. Two thin metal films acting as reflectors and a polymer matrix containing a collection of quantum emitters form a hybrid system for polariton imaging. We show a strong exciton-photon interaction between photons confined in the microcavity and Frenkel excitons of dye molecules placed inside the optical microcavity. We find that exciton polaritons can be imaged and spatially mapped in the optical microcavity by using hyperspectral imaging in the visible region. We envision that our findings will help us to understand exciton polariton formation in the spectral and spatial domains at the same time across different coupling regimes.