WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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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: 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.