Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 2Citation - Scopus: 1Fully Inorganic Colloidal CsPbBr3 Perovskite Nanocrystals with Zn-Doping and Metal Oxide Encapsulation for Luminescent Display Panels(Amer Chemical Soc, 2025-11-07) Khorasani, Azam; Soheyli, Ehsan; Mutlugun, EvrenPerovskite nanocrystals (PeNCs) are emerging as exceptional materials due to their high photoluminescence quantum yield, tunable bandgap, and excellent charge carrier mobility, enabling a wide range of colors and promising applications in optoelectronics and photovoltaics. Despite their advantages, PeNCs face stability challenges caused by environmental factors. In the presented study, a facile and versatile colloidal hot-injection method was used to apply the beneficial aspects of Zn-doping in cesium lead bromide (CsPbBr3) PeNCs. The uniform platelet-shaped Zn-doped CsPbBr3 PeNCs were prepared by doping with a 0.1 molar ratio of zinc-oleate solution in the perovskite precursors during synthesis. Then, zinc-oxide (ZnO) and nickel-oxide (NiO) coating layers were utilized separately to effectively reduce surface defects, encapsulate PeNCs, and improve their stability issues. To fabricate the coated PeNCs with metal oxides, zinc acetate and nickel(II) acetate tetrahydrate solutions were prepared individually and added to the crude perovskite solutions. The quantum yield of Zn-doped CsPbBr3 (CsPb1-xZnxBr3) PeNCs coated with ZnO increased from 50% for bare CsPbBr3 to over 84%, while NiO-coated PeNCs exhibited a higher yield of 90% both of which remarkably enhanced the emission stability. Moreover, NiO coatings represented a proper protection against surface imperfections and improved resistance to external stimuli. The combination of facile/effective preparation method, excellent emission efficiency, and reliable emission stability nominates the prepared colloidal composite for display pixels, detectors, and lasers.Article Citation - WoS: 10Citation - Scopus: 11Recent Advances in CsPbX3 (X = Cl, Br, I) Perovskite NCs@Glass: Structures, Characterizations, and Applications(Wiley-VCH Verlag GmbH, 2025-04-07) Samiei, Sadaf; Lin, Jidong; Soheyli, Ehsan; Nabiyouni, Gholamreza; Chen, DaqinEncapsulation of perovskite nanocrystals (PeNCs) within metal oxide glasses and fabrication of PeNCs@glass composites has emerged as a transformative approach to enhance the stability and functionality of these promising luminescent materials. This review comprehensively examines the current state of research on encapsulation techniques, highlighting their effectiveness in preserving the structural integrity, and optical properties of PeNCs. The advantages and mechanisms by which metal oxide glasses mitigate the degradation of PeNCs are discussed and the tunable properties of metal oxide glass structures for optimizing the photoluminescence and quantum efficiency of encapsulated PeNCs are explored. The review further explores the various experimental techniques for characterizing composites made by nanoscale extreme crystalline species within the short-range ordered (amorphous) microstructures. As the ultimate aim of any advanced material for commercialization, diverse optoelectronic devices of these encapsulated systems, emphasize the potential for improved device performance and longevity. Finally, key challenges and future directions in the field are identified, including the need for scalable fabrication methods and the exploration of novel glass compositions to enhance the encapsulation efficacy. This review aims to provide a comprehensive overview of the advancements in the encapsulation of PeNCs with metal oxide glasses, underscoring their significance in developing next-generation optoelectronic devices.Article Citation - WoS: 5Citation - Scopus: 5Optimization of High Efficiency Blue Emissive N-, S-Doped Graphene Quantum Dots(Elsevier, 2025-02) Tiras, Kevser Sahin; Soheyli, Ehsan; Sharifirad, Zeynab; Mutlugun, EvrenGraphene quantum dots (GQDs) with bright emission at short wavelengths have attracted much attention due to their importance in various applications such as light-emitting diodes. During or after synthesis, several parameters can significantly improve the optical properties of GQDs. This study presents a facile solvothermal method with low-cost precursors using glutamic acid as the carbon source to realize blue emitting GQDs. The positive effects of urea and 1-octanethiol as nitrogen and sulfur dopants on the photoluminescence quantum yield (PLQY) of the prepared GQDs were demonstrated and optimized. The results confirmed the formation of 2.2 nm nanoparticles with a bright emission around 381 nm with a full width at half maximum of 58 nm and a PLQY approaching 70 %. The decay lifetime of the emission also showed a tri-exponential profile with an average lifetime of 2.4 ns. The simplicity of the preparation method without any post-treatment process, together with a high PLQY of 70 % at short wavelengths, nominates the prepared GQDs for optoelectronics and UV light-driven biological purposes.Article Citation - WoS: 17Citation - Scopus: 16Excitation-Independent Deep-Blue Emitting Carbon Dots With 62% Emission Quantum Efficiency and Monoexponential Decay Profile for High-Resolution Fingerprint Identification(IOP Publishing Ltd, 2022-08-15) Savaedi, Soheyla; Soheyli, Ehsan; Zheng, Guangsong; Lou, Qing; Sahraei, Reza; Shan, ChongxinReaching emissive nanomaterials at short wavelengths with a high quantum efficiency (QE) is an attractive task for researchers. This is more demanding in carbon dots (CDs) with diverse applications that usually emit photons at wavelengths around 450-620 nm. In this study, deep blue-emissive doped-CDs (d-CDs) with high photoluminescence (PL) QE up to 62% and excitation-independent properties were prepared via a short-time microwave irradiation method. The prepared CDs showed simultaneous amorphous and crystalline features, with average sizes of 4.75 nm and bright emission color located at 422 nm. It was found that the presence of sulfur-related dopant levels plays a key role in emission properties in such a way that the PL signal drops significantly in the absence of N-acetyl-l-cysteine (NAC) as a dopant source. On the other hand, the trisodium citrate dihydrate (TSC) was selected as a carbon source to form the main carbon skeleton without it no emission was recorded. Monoexponential-fitted recombination trend with an average lifetime of about 10 ns also confirmed excellent PL emission properties with uniform energy levels and minimized defect-contributing recombinations. The practical use of the as-prepared N, S-doped CDs was assessed in fingerprint detection indicating a bright and clear scheme for both core and termination regions of the fingerprint. Simplicity, cost-effectiveness, high-product yield, low toxicity, along with high/stable PL quantum efficiency in deep-blue wavelengths, and demonstrated ability for fingerprint purposes, support the prospective application of these dual doped-CDs for sensing and bioimaging applications.Article Citation - WoS: 3Citation - Scopus: 3Designed Optimization of Photoluminescence Emission for Carbon Dots With Bright Blue Emission at 416 NM and Mono-Exponential Decay Lifetime(Elsevier, 2025-09) Ruwaih, Mohammed Abbas; Soheyli, Ehsan; Naji, Jalil; Mutlugun, Evren; Kikhavani, Tavan; Sahraei, Reza; Abbas Ruwaih, MohammedThe presented study introduces optimized blue-emissive carbon dots (CDs) with high photoluminescence efficiency up to 65 % at 416 nm, large Stokes shift (69 nm), and full-width at half maximum (FWHM) of 73 nm. Xray photoelectron spectroscopy confirmed the formation of carbon-based bonds as the main component of CDs, with reliable amounts of O, S, and N as dopant components. These features, along with single-exponential time-decay profile at long average lifetime of 10.05 ns, supported the significant role of uniformly distributed mid-gap energy levels in the recombination process. The simplicity, low-cost, non-toxicity, and short reaction time of CDs, along with their excellent emission properties in the deep-blue region, make them suitable for use in environmental monitoring and high-contrast bioimaging.Article Citation - WoS: 4Citation - Scopus: 4Bright Green and Blue Solid-State Emitting Carbon Dots With Optimized Photoluminescence Characteristics for Fabrication of High-Performance Light Emitting Diodes(Elsevier Sci Ltd, 2025-09) Havasi, Nasrin; Sahraei, Reza; Soheyli, Ehsan; Lan, Yu; Lou, Qing; Houshmand, Fatemeh; Shan, Chong-XinLuminescent carbon dots (CDs) possess a range of fundamental and technological advantages, including low-cost, and scalable preparation methods, high emission efficiency, tunable electronic properties, and adaptable surface characteristics. However, aggregation-caused quench in solid-state emission of CDs has constrained their applications in luminescent solar-concentrators, and light-emitting devices. This study introduces a rapid and straightforward microwave method for producing bright blue-and green-emissive CDs, with emission peaks at 440 nm and 520 nm, respectively. Blue-CDs showed excitation-dependent feature with a biexponential decay profile and average lifetime of 6.3 ns, while the green one signified an excitation-independent photoluminescence profile with longer average lifetime of 9 ns through biexponential fitting of decay plot. Upon optimization of experimental parameters, reproducible green emission with a high efficiency of 78 % was achieved in dimethyl sulfoxide (DMSO). The critical role of biurea as a nitrogen precursor was elucidated through experimental and computational investigations. Furthermore, owing to the bright solid-state emission of the synthesized CDs, they were utilized as color-converting layers in the fabrication of durable monochrome LEDs, yielding blue and yellowish-green emissions with Commission Internationale de L'E<acute accent>clairage (CIE) coordinates of (0.16, 0.10) and (0.35, 0.57), respectively. This study highlights the potential of CDs for applications in light-emitting panels.