WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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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: 13Citation - Scopus: 15Rational Design of Chemical Bath Deposition Technique for Successful Preparation of Mn-Doped CdS Nanostructured Thin Films With Controlled Optical Properties(Elsevier Sci Ltd, 2021-02) Kharabaneh, Farzaneh Khani; Ghavidel, Elham; Soheyli, Ehsan; Yazici, Ahmet Faruk; Jawhar, Nawzad Nadhim; Mutlugun, Evren; Sahraei, RezaThe introduction of a rational design for depositing internally-doped nanostructured thin films is of great importance for optoelectronics. In this presented work, Mn-doped CdS thin films with high purity in composition were prepared through the chemical bath deposition technique using a nucleation-doping strategy. This work focuses on an improved chemical design to eliminate mostly ignored property of conventionally doped nanoscale thin films. The synthesis strategy was initiated by the initial formation of MnS nuclei in a colloidal depositing solution followed by injection of cadmium precursor to diffuse into the initial nuclei and play the role of host CdS matrix which was the beginning of the deposition process. Upon optimization of the PL-emission, it was revealed that relative intensity of Mn2+-related peak to the excitonic peak has significantly increased (similar to 100 times) in 80 degrees C, pH = 6, and precursor molar ratio of Cd:Mn:EDTA:S equal to 1:3:0.4:5, at deposition time of 300-min. The TRPL measurements further revealed the effective contribution of Mn-related midgap states with long-lived decay curve character, which confirms the success of the designed approach to reach internally doped thin films. It was found that the deposition temperature, amount of Cd/Mn/TA precursors, and deposition time are the most important experimental parameters in the proposed synthesis approach. Due to the versatility, generality, and colloidal advantages of this method, it can be extended to the other structures with various types of dopant agent.Article Citation - WoS: 23Citation - Scopus: 25Preparation of Highly Emissive and Reproducible Cu-In-S/ZnS Core/Shell Quantum Dots With a Mid-Gap Emission Character(Elsevier Science SA, 2020-05) Jawhar, Nawzad Nadhim; Soheyli, Ehsan; Yazici, Ahmet Faruk; Mutlugun, Evren; Sahraei, RezaCopper indium sulfide (CIS) quantum dots (QDs) are one of the newest types of luminescent semiconductors with low-toxicity and earth-abundant features. The present work reports the successful aqueous synthesis of CIS/ZnS core/shell QDs using dual-stabilizing agents of N-acetyl-L-cysteine and trisodium citrate. Off-stoichiometric QDs with In-rich compositions were found to be very small and highly emissive after coating by a shell of wide bandgap ZnS. The effect of various experimental parameters was evaluated to achieve highly reproducible QDs with bright reddish emission. Results showed a significant contribution of mid-gap defect states in the recombination processes (based on the gradual increase in absorbance recorded for samples, relatively high Urbach energy, large Stokes shift, large FWHM value in PL spectra, as well as the long-lived PL decay time). In addition, the chemical stability of samples was investigated using highly oxidant H2O2 agent and results demonstrate their superior stability. The combination of low-toxicity, intense and stable emission, along with synthetic advantages demonstrates that the present aqueous-soluble and emissive QDs can be considered as an excellent bio-photonic structure suitable for different fields of biological imaging and diagnostics. (C) 2020 Elsevier B.V. All rights reserved.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: 6Citation - Scopus: 9Impact of Red Emissive Zncdtes Quantum Dots on the Electro-Optic Switching, Dielectric and Electrochemical Features of Nematic Liquid Crystal: Towards Tunable Optoelectronic Systems(Elsevier, 2023-06) Seidalilir, Zahra; Shishehbor, Sepideh; Soheyli, Ehsan; Sabaeian, MohammadIn the present study, the concentration-dependent dielectric, electro-optical, and electrochemical properties of ZnCdTeS quantum dots (QDs) doped E7 nematic liquid crystal (NLC) mixtures were investigated. The dielectric permittivity components (epsilon(parallel to) and epsilon(perpendicular to)) and dielectric anisotropy (Delta epsilon -epsilon(parallel to) - epsilon perpendicular to.) of NLC samples containing varied concentrations of ZnCdTeS QDs (i. e. 0.10, 0.25, 0.50, 0.75, and 1 wt%) were measured at various temperatures. In the nematic phase, the results demonstrated that e. increases much more than epsilon(perpendicular to) upon an increase in the concentration of ZnCdTeS QDs. Delta epsilon enhanced as the concentration of QDs increased, reaching a maximum at 0.50 wt%, then decreased with further addition. Dielectric measurements revealed the formation of self-aligned QD arrays along the nematic director, which act similarly to multiple parallel capacitors in the NLC system. Moreover, electro-optical studies illustrated the significant effect of QDs doping on lowering the threshold voltage and response time. Interestingly, the optical switching-off time of NLC containing 0.50 wt% of the QDs decreased by similar to 50% compared to that of the pure E7 sample. The reduced screening effect resulting from the QDs ioncapturing mechanism, enhanced effective intermolecular interactions, and increased dielectric anisotropy in the NLC system are the major factors responsible for the improved electro-optical characteristics. The impedance behavior of NLC cells was studied in the frequency range of 0.1 Hz-100 kHz. It indicated that the addition of ZnCdTeS QDs results in a remarkable increase of 96% in the electrical conductivity of the NLC system. Furthermore, the QDs doping significantly improved the NLC device's charge capacitance. Such studies would undoubtedly be beneficial for designing next-generation tunable optoelectronic systems since QDs can be utilized for tuning the dielectric anisotropy, electro-optical characteristics, charge capacitance, and conductivity of NLCs.Article Citation - WoS: 45Citation - Scopus: 46Exploring CsPbx3 (X = Cl, Br, I) Perovskite Nanocrystals in Amorphous Oxide Glasses: Innovations in Fabrication and Applications(Wiley-VCH Verlag GmbH, 2023-12-10) Samiei, Sadaf; Soheyli, Ehsan; Vighnesh, Kunnathodi; Nabiyouni, Gholamreza; Rogach, Andrey L.Metal halide perovskites with excellent optical and electronic properties have become a trending material in the current research. However, their limited stability under ambient conditions degrades quality and threatens their potential commercialization as optoelectronic devices. Various approaches are adopted to improve the stability of perovskite nanocrystals (PeNC) while maintaining their advantageous optical properties, particularly strong luminescence. Among different possible improvement strategies, encapsulation of PeNCs within the amorphous glass matrices of inorganic oxides has drawn widespread attention because it ensures high resistance against chemical corrosion and high temperature, thus enhancing their chemical, thermal, and mechanical stability with improved light-emission characteristics. In this article, two types of materials, namely all-inorganic metal halide PeNCs and amorphous oxide glasses are briefly introduced, and then the methods are reviewed to fabricate and improve the quality of PeNC@glass composites. These methods are classified into three universal categories: compositional modification, structural modification, and dual encapsulation. In the final part of this review paper, examples of applications of PeNCs@glass composites in light-emitting devices and displays, data storage and anti-counterfeiting, lasing, photodetectors and X-ray detectors, photocatalysis, optical filters, solar concentrators, and batteries are provided.Article Citation - WoS: 5Citation - Scopus: 5Enhanced Photoluminescence Emission Intensity and Stability of Deep Blue-Emissive (Et 3 Nh)pbbr 3 Perovskite Nanocrystals by Using Metal-Organic Frameworks(Elsevier Sci Ltd, 2024-08) Hemmati, Tayebeh; Naghipour, Ali; Sahraei, Reza; Soheyli, EhsanThe primary obstacle faced by researchers in the field of luminescent metal-halide perovskites is their inherent instability, prompting a shift in focus towards enhancing the stability of perovskite nanocrystals (PNCs). One of the promising approaches to address this challenge involves the utilization of metal-organic frameworks (MOFs) to fabricate PNCs@MOF composites. The present study reports a facile and low-cost colloidal strategy to prepare (Et3NH)PbBr3 PNCs followed by their encapsulation within UiO-67 to enhance their photoluminescence (PL) emission stability. The PNCs and modified UiO-67 were prepared separately via simple and efficient ligandassisted reprecipitation (LARP) and hydrothermal methods, respectively. After modification of the UiO-67, the pore sizes experienced a substantial increase from 1.90 to 28.84 nm which significantly facilitated the localization of PNCs within the porous matrix. Under a full survey of experimental conditions, the resulting (Et3NH) PbBr3@UiO-67 composite exhibited a bright deep-blue emission at around 410 nm with an emission quantum yield of 52 %. The emission durability of the fabricated PNCs@MOF composites was assessed against temperature and long-time of storage, confirming the superior advantages of MOF even at elevated temperatures of up to 100 degrees C. The stable and luminous deep-blue emission displayed by the PNCs@MOF composites in this investigation, offers a promising advancement in materials development for optoelectronic applications.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.