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Basic Parameter Extraction From An Organic Solar Cell Through The Single Diode Model And A Metaheuristic Technique With The Lambert W Function
(Ieee, 2014) Tutkun, Nedim; Elibol, Erdem; Maden, Dinçer
Recently solar power has increasingly been used to generate electricity worldwide through photovoltaic (PV) systems. The electrical performance of each PV module plays major role in maximum power transfer. In order to absorb the maximum power from such systems, optimal output voltage and current should be obtained from the I-V characteristics of previously developed models. It is fact that, this is a relatively uneasy task because manufacturer's data sheet is confined to limited number of measured values. In this study, the hybrid genetic algorithms method is employed to extract basic parameters of the ideality factor and the parasitic resistances in the single diode model to transfer maximum power from a PV module to a resistive electrical load. Optimal parameters in the circuital model are found using the I-V characteristic of a silicon diode expressed by the Lambert W function. The results are meaningful and encouraging for maximum power transfer under certain conditions.
CdSeTe Kuantum Noktaları ile Bromo Krezol Mor Kombinasyonunun Spektrofotometrik Değerlendirmesi
(2023) Demirci, Tuna; Elibol, Erdem
Kuantum noktalar (QDs) sahip oldukları benzersiz optik ve elektronik özellikleri ile son yıllarda birçok farklı teknolojik alanda popüler hale gelmişlerdir. Bu durum QD'lar ile organik bileşiklerin etkileşimine olan ilgiyi arttırmaktadır. Bu çalışmada bu ilgiye temel alarak, CdSeTe QD'lar ile Brom Krezol Moru (BCP) kloroform içerisinde oda sıcaklığın da etkileşimini ve CdSeTe QDs/BCP yapısının spektroskopik olarak karakterizasyonu açıklamayı amaçlamıştır. Bu amaç doğrultusunda CdSeTe QDs/ BCP oluşumunun etkileşimleri spektroskopik olarak Fourier dönüşümlü kızılötesi spektroskopisi (FTIR), absorbans ve emisyon üzerinden karakterizasyon çalışmaları yapılmıştır. BCP'nin CdSeTe QD'lar ile hibritleşmesiyle QDs'nin lüminesans pikinde 19 kat azalma tespit edilmiştir. Bununla birlikte Brom Krezol Moru (BCP) ile hibritleşen CdSeTe QD'lar BCP'nin soğurma özelliğini 112.8 katına kadar arttırmıştır.
CdSeTe quantum dot based fluorescence sensor systems for detection of vitamin C, folic acid and glucose
(Elsevier, 2024) Bakay, Melahat Sevgul; Elibol, Erdem; Cadirci, Musa
The levels of metabolites in the human body provide significant clues for the diagnosis, staging, and therapy planning of diseases. Recently, fluorescence-based metabolite detection methods have become popular thanks to their important advantages such as using less sample, not requiring prior preparation, and responding quickly. In this regard, quantum dots (QDs) are unique materials in metabolite detection studies due to their well-known fluorescence-emitting structures, high luminescence, tunable size, and high absorption cross-section ratio. In this experiment, we synthesized the mercaptopropionic acid (MPA) capped CdSeTe-alloy QDs and investigated their metabolite detection performance using vitamin C (VitC), folic acid (FA) and glucose (Glu). Under the optimized conditions (pH, QD concentration and incubation times), the quenching fluorescent responses were obtained from metabolite-added CdSeTe QD solution which ascribed to the Forster resonance energy transfer (FRET) mechanism. The linearity ranges and limit of detection (LOD) values for VitC, FA and Glu were determined. The presented method has also been applied to quantify the amount of metabolites in human blood serum samples in the linear ranges of 10-20 mu g/mL for CVit, 7.5-20 ng/mL for FA, and 0.25-1.5 mg/mL for glucose, with an accuracy of over 95 %. This sensor system has also shown a noteworthy advantage regarding sensitive, selective, reliable and cost-effective metabolite detection technique.
CdTe nanomalzeme ile güneş hücresi üretimi ve karakterizasyonu
(Düzce Üniversitesi, 2018) Elibol, Erdem; Tutkun, Nedim
Dünya genelinde enerjiye duyulan ihtiyacın artması buna karşın fosil yakıtların hızla azalması alternatif enerji kaynaklarının önemini artırmaktadır. Mevcut silisyum, germanyum bazlı birinci nesil güneş hücrelerinin yüksek maliyeti ve alternatif olarak ortaya çıkan ikinci nesil güneş hücrelerinin enerji dönüşüm verimlerinin %13 civarında kalması üçüncü nesil güneş hücreleri üzerine yoğunlaşma gereğini ortaya çıkarmıştır. Öyle ki henüz gelişim aşamasında olan üçüncü nesil güneş panelleri verim olarak birinci nesil güneş panellerini şimdiden yakalamışlardır. Üçüncü nesil güneş panelleri içinde Kuantum Nokta Duyarlı Güneş hücreleri (KNDGH) son beş yılda sergiledikleri aşama ile dikkat çekmektedir. Kolay işlenebilirlikleri, ayarlanabilir boyut ve bant aralıkları ve Çoklu Eksiton Üretimi (MEG) gibi benzersiz opto-elektronik özellikleri kuantum noktaları ilgi çekici hale getirmektedir. Bu özellikler KNDGH için teorik olarak enerji dönüşüm veriminin %44'e kadar çıkabileceğini göstermektedir. Bu çalışmada CdTe KNDGH tasarımı üzerine odaklanılmıştır. Tez çalışması 3 temel bölüme ayrılmıştır; CdTe KN sentezlenmesi, CdTe KN'nın tedavi edilmesi ve sentezlenen CdTe KN'lar ile KNDGH tasarlanması. CdTe KN sentezlenmesi için sıcak enjeksiyon metodu kullanılmış olup klasik metot ile sentezlenen CdTe KN Fotolümünesans Kuantum Verimi (PLQY) %8,12 olarak bulunmuştur. Sıcak enjeksiyon metodu daha sonra Kanula metoduyla modifiye edilmiş ve sentezlenen CdTe KN'nın PLQY değeri %25,66 ya çıkarılmıştır. Ayrıca KN'nın PL Maksimum Pik Noktasının Yarı Noktası (FWHM) 27nm seviyesine indirilmiş olup literatürdeki en yüksek monodispersi özelliği sergileyen organometalik CdTe KN sentezlenmiştir. Daha sonra sentezlenen CdTe KN'ya klorür pasifikasyon işlemi uygulanmış, farklı miktarda klorür (12-96 CdCI2/nm2) iyonu KN'ya enjekte edilmiştir. Yapılan analizler sonucunda 60 CdCI2/nm2 tedavisiyle CdTe(CI) KN'nın PLQY değeri %87,33'e çıkarılmıştır. Yapılan pasifleştirme tedavisi Kanula metoduyla %70 tekrarlanabilir hale getirilmiştir. Ayrıca CdTe KN'nın oksijen ortamında dayanım süresi 3 kat arttırılmıştır. Sentezleme ve tedavi işlemlerin ardından KNDGH tasarım aşamasına geçilmiştir. Bu aşamada KN'nın boyutu, TiO2 kalınlığı, FTO/TiO2 yüzeyine yapılan tedavi, CdTe KN'nın yüzeye tutturulması, redoks çifti ve toplayıcı elektrot seçimi üzerine birçok iyileştirme çalışması yapılmıştır. Tüm optimizasyon işlemleri sonucunda FTO/TiCI4/TiO2 (22µm) /TiCI4 /36 CdCI2/nm2 CdTe(CI) KN yüzey foto anot olarak kullanılırken, FTO/Pt yüzeyin toplayıcı elektrot olarak seçilmiştir. Bu iki yüzey arasına I-/I3- redoks çifti enjekte edilmiştir. Tasarlanan KNDGH için Jsc 3,22 mA/cm2, Voc 0,821V olurken, dolum faktörü %57,192 ve verim %1,515 olarak bulunmuştur. Bu verim değeri literatürdeki organometalik CdTe kullanılarak elde edilen en verimli (%0,197) CdTe KNDGH verimine göre 7,97 kat daha iyidir.
Charge Recombination Suppressed CdSeS/CdSe/ZnS QDSSC Design
(2021) Elibol, Erdem
The interest in quantum dot sensitized solar cells (QDSSC), which has theoretically proved to have up to 44% energy con- version efficiency in recent years, is growing rapidly. Although it has theoretically high efficiency value, PCE obtained in studies with QDSSCs is far from these values. This situation shows that there are many difficulties to be solved in QDSSC technology. One of the main challenges in QDSSC technology is irradiated load recombination occurring in QDSSC. For this reason, in this study, it is about using CdSeS QDs as an alternative to the most used CdS QDs in the literature in order to supp- ress the load recombination between TiO2 surface and electrolyte and QD surfaces. In the study, while CdS and CdSeS QDs were coated on the TiO2 surface with SILAR method, the previously synthesized CdSe QD was coated with chemical deep deposition method. Surfaces were last treated with ZnS QDs. An optimization study was carried out to determine the ideal number of CdSeS coatings for QDSSCs. As a result, the Jsc and Voc values for TiO2/CdSeS4/CdSe/ZnS QDSSCs were 8.799 mA/ cm2 and 0.795 V, respectively, while the PCE value increased to 4.452%.
Comparison between NiO and MnO2 nanoparticles deposited on graphene-coated nickel foam for water purification applications
(Elsevier, 2023) AlAnazi, Maha; Ghrib, Taher; Ercan, Filiz; Kotb, Essam; Bubshait, Ruqaiyah; Almilad, Fatimah; Elibol, Erdem
Nanoparticles of NiO, and MnO2 nanoparticles were successfully synthesized on graphene-coated Nickel foam (NFG) substrates for the synthesis of dual-functional specimens for antibacterial and photocatalytic applications. The morphological, structural, and optical properties were investigated thanks to the techniques of scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-Vis, and photoluminescence spectroscopy. It was observed from XRD analysis that alpha-MnO2 and NiO nanoparticles were deposited with high purity as a thin film on NFG substrates. The photocatalytic efficiency of the synthesized materials was tested on a Methylene blue (MB) solution as a target dye pollutant and the obtained results indicate a good degradation rate under visible light irradiation. Antibacterial activity was tested on Staph aureus, Pseudomonas aeruginosa, and the yeast Candida albicans. The obtained results show that MnO2/NFG and NiO/NFG specimens constitute good candidates for the treatment of wastewater.
Design of CdSexS1-x/ZnS Quantum Dot Sensitized Solar Cell
(American Institute of Physics Inc., 2022) Elibol, Erdem
Quantum Dot Sensitized Solar Cells (QDSSCs) are a high potential element of third generation solar energy systems, which has recently been viewed as an alternative to first- and second-generation solar cells. In this study, CdSexS1-x QDSSCs were designed and their performances were examined depending on parameter changes. TiO2 surfaces are coated on Fluorine doped tin oxide glass (FTO) surface in 3 layers by doctor blade method. CdSexS1-x QDs were coated on TiO2 surface by Successive Ionic Layer Adsorption and Reaction (SILAR) method, and it was aimed to improve surface passivation and electron transfer with ZnS coated with SILAR method. In the study, the selenium and sulphur amount in CdSexS1-x QDs were tested at different rates, and SILAR cycles of QD and ZnS were tested between 1-5 cycles. It was determined that the highest Power Conversation Efficiency (PCE) value was obtained with CdSe0.8S0.2 QDSSC where the amount of Se was 4 times the amount of S, CdSexS1-x QDs were coated as 5 SILAR cycles and ZnS was coated as 3 SILAR cycles. The PCE of CdSe0.8S0.2 QDSSCs was found to be 1.87%. In this case, it has been clearly demonstrated that modulation of Se to CdS QDs, which is one of the most used QDs in the literature, increases the performance of the QDSSC. In addition, the effects of the SILAR cycle, in which the amount of QD coated on the surface is controlled, and therefore the thicknesses of the QDs on the QDSSC performance have been discussed. © 2022 American Institute of Physics Inc.. All rights reserved.
Effect of Al0.1Ga0.9As thickness on the structural, optical, thermal, and electrical properties of (Al0.1 Ga 0.9As)/GaAs heterojunctions
(Elsevier Ltd, 2023) Al-Naghmaish, Aishah; Ghrib, Taher; Dakhlaoui, H.; AL-Saleem, N.K.; Ercan, F.; Kayed, Tarek S.; Elibol, Erdem
Al0.1Ga0.9As nano-films of various thicknesses were deposited on GaAs substrate and examined using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), UV–Visible spectrophotometry, Photoluminescence (PL), Electrochemical Impedance Spectroscopy (EIS), and Photothermal Deflection (PTD). The PTD technique is used to analyze the effect of Al0.1Ga0.9As thickness on thermal properties and showed its sensitivity to weak structural changes. By increasing the Al0.1Ga0.9As thickness, the crystallinity was degraded, an infrared emission centered at 997.4 nm whose intensity is the highest for 50 nm was observed. A pn junction was formed for thicknesses higher than 400 nm, the band gap was increased from 1.59 to 1.68 eV. The thermal conductivity increased from 35.3 to 37.3 W m? 1 K?1 and the thermal diffusivity increased from 0.195 to 0.22 cm2 s?1. As a result of this investigation, the Al0.1Ga0.9As/GaAs can be considered for potential applications in photoelectric and thermoelectric devices. © 2023 The Author(s)
Effects of different counter electrodes on performance of CdSeTe alloy QDSSC
(Pergamon-Elsevier Science Ltd, 2020) Elibol, Erdem
Quantum Dot Sensitized Solar Cells (QDSSC) is one of the most focused energy sources among the 3rd generation energy sources with the theoretically promised energy conversion efficiency. Even though the experimental studies have been far from the maximum efficiency that should be obtained theoretically, efficiency continues to increase rapidly with new application and treatment methods. One of the problems to be solved in QDSSC technology is the selection of the counter electrode (CE) and electrolyte that is compatible with the synthesized QD, and the studies on this subject are limited compared to other studies. In this study, CdSeTe QDSSCs were designed in combination with 3 different CE (Au, Pt, Cu2S) and 2 different electrolytes (triiodide, polysulfide) and the effects of CEs on QDSSC performance were compared. As a result of the study, it was determined that the use of Cu2S CE/polysulfide electrolyte in the design of CdSeTe QDSSS increased PCE up to 1.408%. The highest filling factor (FF) and highest V-oc values were obtained by Pt CE/triiodide electrolyte in these studies and these values were 60.664% and 0.730 V, respectively.
Exergetic, exergoeconomic, and sustainability analyses of diesel-biodiesel fuel blends including synthesized graphene oxide nanoparticles
(Elsevier Sci Ltd, 2022) Uysal, Cüneyt; Ağbulut, Ümit; Elibol, Erdem; Demirci, Tuna; Karagöz, Mustafa; Sarıdemir, Suat
In this study, graphene oxide nanoparticles were synthesized and added to 85 vol% diesel + 15 vol% biodiesel (D85B15) blend with amounts of 100 ppm, 500 ppm, and 1000 ppm to prepare D85B15GO100, D85B15GO500, and D85B15GO1000 blends, respectively. The prepared fuels were tested in a compression ignition diesel engine. The experiments were performed on various engine loads ranging from 3 Nm to 12 Nm with intervals of 3 Nm at fixed crankshaft speed of 2400 rpm. The results obtained from the experiments were used in the exergetic, exergoeconomic, and sustainability analyses of test engine. According to the results, D85B15GO100 had the highest exergy efficiency and sustainability index and the second-cheapest specific exergy cost of crankshaft work. As a result, at 12 Nm, the exergy efficiency, specific exergy cost of work produced by crankshaft, and sustainability index values of test engine were 25.82%, 75.82 $/GJ, 1.348 for D85B15, whereas these values were 27.05%, 77.52 $/GJ, 1.371 for D85B15GO100, respectively. Increase in graphene oxide nanoparticle content in the blend led to decrease in the exergy efficiency and sustainability index and increase in the specific exergy cost of crankshaft work. Finally, it can be concluded that D85B15GO100 is optimal fuel compared to the fuels tested in this study.
Fluorescent CdTe/ZnS Core/Shell Quantum Dots for Sensitive Metabolite Detection in Real Samples
(Springer/Plenum Publishers, 2025) Agbulut, Melahat Sevgul Bakay; Elibol, Erdem; Cadirci, Musa; Demirci, Tuna
This study highlights the aqueous synthesis of CdTe/ZnS core/shell quantum dots (QDs) and their application as fluorescence sensors for detecting critical metabolites, including folic acid, glucose, and vitamin C, in real biological samples. The synthesized QDs exhibit excellent quantum efficiency, stability, and biocompatibility, enhanced by mercaptopropionic acid (MPA) ligands, enabling eco-friendly and accurate sensing. Detection limits of 0.84 mu g/mL for folic acid, 0.33 mM for glucose, and 1.15 mu g/mL for vitamin C were achieved with high linearity (R-2 > 0.97). These results underscore the potential of CdTe/ZnS QDs in advanced biosensing technologies, offering sensitive and selective metabolite detection through a robust FRET-based mechanism. The versatility and aqueous solubility of these QDs pave the way for their integration into multiplex diagnostic systems for enhanced biomedical applications.
High efficiency green and red emitting CdSeTe quantum dots: Synthesis and PLQY improvement for optical applications
(Elsevier Science Sa, 2025) Elibol, Erdem; Demirci, Tuna; Koc, Durukan
Obtaining stable QDs with different emission colors and high PLQY values for optoelectronic applications is important. There are currently applied treatment methods to increase the PLQY value and stabilization of QDs. On the other hand, variations in the surface-to-volume ratio associated with changes in QD size indicate that the treatment methods applied must be optimized according to the specific size of the QDs. This study focuses on the optimization of the synthesis and treatment processes of green and red emission CdSeTe QDs with high PLQY for use in optoelectronic devices. Initially, the synthesis processes for green and red emission QDs were optimized according to precursor molar amounts, synthesis time and synthesis temperature. Then, chloride treatment, CdS and ZnS shell coating methods were optimized and applied separately to increase the PLQY values of these QDs. The results showed that the PLQY value increased up to 95.23 % with 30 % CdCl2 treatment by mass for green emitting CdSeTe QDs and up to 96.31 % with 40 % CdCl2 chloride treatment by mass for red emitting QDs. The study includes a comprehensive comparison of emission, absorption, XRD, elemental analysis, CV, PL lifetime, HR-TEM analysis and stabilization analysis for the synthesized CdSeTe QD types.
Improved photoluminescence and monodisperse performance of colloidal CdTe quantum dots with Cannula method
(Korean Institute Chemical Engineers, 2019) Elibol, Erdem; Elibol, Pınar Sevim; Çadırcı, Musa; Tutkun, Nedim
Colloidal quantum dots are nano semiconductor materials that have been found in many applications, producing multiple exciton generation, unique optical and electronic properties, adjustable in size and bandwidth. Synthesized QDs are expected to exhibit high photoluminescence quantum yield and monodisperse properties according to their application area. Cannula method was adapted together with the organometallic synthesis method for the first time in the literature to increase the photoluminescence quantum yield of organometallic CdTe QD and minimize the full width at half maximum value of the photoluminescence band. Injection of precursors by the Cannula method is much faster than the injecting with the conventional method of using a glass syringe, which limits the size distribution in the solution during synthesis. In addition, the fastest injection method using Cannula method yields the shortest full width half maximum value of 27.20 nm for CdTe QDs in the literature. The photoluminescence quantum yield value of the CdTe QDs synthesized by the classical method was 8.12 +/- 2.1%, while the photoluminescence quantum yield of the CdTe QDs synthesized by the Cannula method was increased to 25.66 +/- 2.1%.
Improving CdTe QDSSC's performance by Cannula synthesis method of CdTe QD
(Elsevier Sci Ltd, 2019) Elibol, Erdem; Tutkun, Nedim
In this study, CdTe Quantum Dots (QDs) used in QD Sensitized Solar Cell (QDSSC) design were synthesized by Cannula method. Cannula method is a method used to minimize problems occurring in hot injection method, while reducing the Full Width Half Maximum (FWHM) value to 27.20 nm, QD's Photoluminescence Quantum Yield (PLQY) increased to 25.66 +/- 2.1%. This study was carried out to determine the effects of CdTe QDs synthesized by Cannula method on CdTe QDSSC application. Firstly, CdTe QDSSCs with the same parameter values (TiO2 thickness, redox couple, collecting electrode, coating technique and duration) were designed with CdTe QDs synthesized by using classical method and Cannula method. The Photo Conversion Efficiency (PCE) of QDSSCs using CdTe QDs synthesized by Cannula method was 0.234%, 2.68 times bigger than the PCE of the CdTe QDSSC synthesized by the classical method. Then, to determine how the size of CdTe QD affects the PCE of CdTe QDSSCs, 6 CdTe QDSSCs were designed by using different size CdTe QDs which were synthesized by Cannula method. In addition, the FTO/TiO2 surface was treated with TiCl4 in CdTe QDSSCs designed. The decrease in the size of the CdTe QD has been found to increase the PCE of CdTe QDSSC. As a result, the PCE of CdTe QDSSC was increased to 0.385% by using 2.80 nm CdTe QDs synthesized by Cannula method. This PCE is the highest value in CdTe QDSSCs designed using CdTe QDs synthesized in the literature by hot injection method. The current density (J(sc)) and open circuit voltage (V-oc) of the designed CdTe QDSSC were found to be 1.292 mA/cm(2) and 0.724 V, respectively.
Improving the performance of CdTe QDSSCs by chloride treatment and parameter optimization
(Elsevier Sci Ltd, 2019) Elibol, Erdem; Elibol, Pınar Sevim; Çadırcı, Musa; Tutkun, Nedim
In this study, organometallic CdTe(Cl) Quantum Dot Sensitized Solar Cells (QDSSCs) using cadmium chloride (CdCl2) treated CdTe QDs were designed for the first time in the literature. The study is divided into 3 basic sections; synthesis of CdTe QD, treatment of CdTe QD with CdCl2 and design CdTe(Cl) QDSSCs. The hot injection method modified by Cannula method was used to synthesize organometallic CdTe QDs. The chloride passivation procedure was applied to CdTe QD with injection of different amount of chloride (12-96 CdCl2/nm(2)) into the CdTe solution. Uv-vis, Photoluminescence (PL), PL Quantum Yield (PLQY), Full width Half Maximum (FWHM) analyses were performed for all CdTe QDs which were synthesized and treated with chloride. As a result of the analyses, PLQY value was increased from 25.66 +/- 2.1 to 87.33 +/- 2.1% with 60 CdCl2/nm(2) treatment. To determine the effects of chloride treatment on QDSSC, CdTe QDSSCs were designed using 6 different CdTe (CI) QDs obtained by different amounts of chloride treatments applied to the surfaces of CdTe QDs. After that, TiO2 thickness, collector electrode selection were chosen by experimental optimization. As a result of the study, FTO/TiCl4/TiO2 (22 mu m)/TiCl4/(36 CdCl2/nm(2)) CdTe(Cl) QD surface was used as the photo anode at the end of all optimization procedures, while FTO/Pt was selected as the collecting electrode surface. I-/I-3(-) redox pairs were injected between these two surfaces. For the designed QDSSC, J(sc), V-oc, filling factor (FF), Power Conversion Efficiency (PCE) were found 2.842 +/- 0.10 mA/cm(2), 0.810 +/- 0.019 V, 56.630 +/- 1.79%, 1.306 +/- 0.10% respectively. This efficiency value is 5.58 times better than the most efficient CdTe QDSSC's efficiency (0.234%) obtained by using organometallic CdTe QDs in the literature.
Interaction and Characterization of The Triarylmethane Dye Bromophenol Blue with CdSeTe Quantum Dots
(2021) Elibol, Erdem; Demirci, Tuna
The use of hybrid associates in biological, optoelectronics and energy fields are increasing dayby day. In this context, in this study, CdSeTe Quantum dots (QD): Bromophenol Blue (BPB)hybrid associates were studied for the first time in the literature and their spectroscopiccharacterizations were examined. In the study, CdSeTe QDs were synthesized withtrioctylphosphine (TOP) ligands by hot injection method, and it was planned that the BPBwould passivate the surface of the QD by interacting with the TOP ligand of the CdSeTe QDs.CdSeTe QD: BPB hybrid associates were prepared in different concentrations, and the effectsof QD: BPB ratios on absorbance and emission characterizations were examined. Structureshave been characterized using Uv-vis, PL, ICP-OES and FTIR. With the results found, thepredictive mechanism has been put forward.
Investigating the effect of Zn doping and temperature on the photoluminescence behaviour of CuLaSe2 quantum dots
(Wiley, 2024) Cadirci, Musa; Elibol, Erdem; Demirci, Tuna; Kurban, Mustafa
In this study, CuLaSe2 and ZnCuLaSe2 quantum dots (QDs) with a mean size of similar to 4 nm were synthesized and characterized, and their temperature-dependent photoluminescence (PL) properties were studied in the temperature range from 90 to 300 K for the first time. The results show that the obtained QDs were spherical and revealed excitonic band gaps. The PL intensity for both types of materials decreased when increasing the temperature to 300 K, which was attributed to the nonradiative relaxation and thermal escape mechanisms. As the temperature was increased, the PL linewidths broadened, and PL peak energies were red shifted for both types of QDs due to the exciton-phonon coupling and lattice deformation potential mechanisms. In addition, we found that as the temperature was decreased, the PL spectrum of ZnCuLaSe2 QDs contained two extra components, which could be attributed to the shallow defect sites (low energy peak) and the crystal phase transition process (high energy peak). The spectrum of CuLaSe2 QDs contained one extra component, which could be attributed to the crystal phase transition process.
Investigation of Dependence of Optoelectronic Properties of P3HT: PCBM Based Organic Solar Cells on Active Layer Thickness
(2020) Şağam, Nazan; Elibol, Erdem; Gökşen, Kadir
This paper presents the production and results of optoelectronic characterization process forITO/PEDOT:PSS/P3HT:PCBM/Al organic solar cells (OSC). OSCs were produced in open air environment withvarious P3HT:PCBM active layer thicknesses of 70, 110, 140, 175 and 190 nm. The diode properties of the solarcells in the dark have been investigated by using current-voltage (I-V) measurements. The absorptioncharacteristics have been investigated by using transmission spectroscopy, and optical band gap energy (Eg) foreach sample has been calculated. Solar cell parameters for each solar cell has been investigated by using currentdensity-voltage (J-V) measurements under AM 1.5 solar raditation, and important solar cell parameters have beencalculated. It was observed that fill factor (FF) value of the solar cells increase between 0.3239 and 0.3409 withdecreasing diode ideality factor (n) value. The highest value of PCE was found to be 0.59, which belongs to thecell having 140 nm P3HT:PCBM thickness.
Long-term performance investigation of different solar panels in the West Black Sea Region
(Springer, 2024) Elibol, Erdem; Dikmen, Osman
Photovoltaic panels play a vital role in expanding renewable energy usage and mitigating environmental impacts. Ensuring the efficient integration of PV panels in diverse regions worldwide relies on precise calculations, considering factors like sunlight variability, climatic conditions, and grid connectivity. This study evaluates the performance of amorphous silicon (a-Si), polycrystalline silicon (pc-Si), and monocrystalline silicon (mc-Si) solar panels in the West Black Sea's Duzce province, Turkey. The respective capacities of these panels are 2.4 kW, 2.64 kW, and 2.35 kW. Over 6 years (2014-2019), we collected detailed data, including temperature, irradiance, wind speed, and power outputs, totaling 7.39 kW. We calculated the performance ratio, power conversion efficiency, and degradation rate for a-Si, pc-Si, and mc-Si panels under varying environmental conditions. The findings showed that a-Si panels had a PR of 71.391%, pc-Si panels scored 75.394%, and mc-Si panels excelled with a PR of 85.113%. The annual average DR relative to PR was - 0.577%/year, - 0.583%/year, and - 0.582%/year, respectively. PCE over the 6-year period was 4.519% for a-Si panels, while pc-Si and mc-Si panels achieved 10.478% and 12.736%. Six-year experimental study conducted in real-world conditions provides highly reliable data valuable to PV panel stakeholders and offers robust insights, particularly regarding region-specific panel selection. The results indicate monocrystalline silicon (mc-Si) as the most suitable PV panel type for Duzce, affirming its potential in the West Black Sea Region.
Mineral oils modified with CdSeTe QDs for improved stability and dielectric performance in high-voltage applications
(Springer, 2025) Bicen, Yunus; Elibol, Erdem; Demirci, Tuna
This study explored the application of CdSeTe quantum dots (QDs) in mineral oils for high-voltage applications through a comprehensive approach. CdSeTe QDs were synthesized using an organometallic method and added to mineral oil at concentrations of 1 mg/L (C1), 5 mg/L (C2), and 10 mg/L (C3). The samples' stability condition was monitored for a long period, and physicochemical tests were performed. Experimental results show that QD-modified oils have enhanced electrical properties compared to the base oil. The breakdown voltage was in the range of 17 to 23 kV for the base oil, while the breakdown voltage was in the range of 20 to 39 kV for the QD-modified (C2) insulating fluid sample. Throughout the 25-day monitoring period, the QDs were found to be properly dispersed in oil and free of aggregation in all samples. Values such as density and viscosity remained fairly constant due to the relatively low concentration ratio. However, an increase in total acid number was observed with increasing concentration. These results imply that QD-enhanced insulation oils may have applications in high-voltage applications in the future. The main innovation of this study lies in demonstrating that CdSeTe QDs can significantly enhance the dielectric strength of mineral oils while maintaining their essential physicochemical properties, offering a novel approach for improving insulation performance in high-voltage applications.

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