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Öğe Boosting inverted type organic solar cell efficiency through the use of spray coated Y and Sn co-doped zinc oxide nanoparticles as an electron transport layers(Springer, 2023) Gegin, Keziban; Demir, Ahmet; Ozturk, Sadullah; Erkovan, Mustafa; Kosemen, ArifThe purpose of this study was to investigate the use of zinc oxide nanoparticles (ZnO NPs) as an electron transport layer (ETL) in inverted type organic solar cells (IOSCs). Three different forms of ZnO NPs were synthesized: undoped, doped with Sn or Y, and co-doped with combinations of these elements (Sn-co-doped Y). The ZnO NPs ETL was introduced into the solar cells using a spray coating technique, resulting in a bulk heterojunction structure of ZnO NPs/P3HT:PCBM/V2O5/Ag. Various methodological approaches were used to characterize the ZnO nanoparticles, including scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and ultraviolet/visible spectrophotometer. The current-voltage performance of the solar cells was measured under 100 mW/cm(2) white light. The results showed that the efficiency of the solar cells using undoped ZnO as ETL was 3.09%. However, the use of 0.5 wt% Sn and 1 wt% Y co-doped ZnO as ETL significantly improved the efficiency to 3.67%, representing an approximate increase of 19% compared to the undoped ETL. All experimental processes were performed under ambient air conditions. In conclusion, this study highlights the potential of using doped or co-doped ZnO NPs as ETL for fabricating IOSCs at low temperatures and improving their efficiency.Öğe Comparison of Typical PV Module Performances Based on the Circuit Models(Ieee, 2018) Tutkun, Nedim; Gegin, Keziban; Sarma, Nur; Salam, Z.In PV systems, it is usually expected that power generation under varying conditions at any time should be maximum as much as possible. Therefore, it is essential to build a circuit model based on a widely used single or double diode model under instantly varying conditions with minimum estimation error through the measured values in the manufacturers' data sheet. It is fact that these approximate circuits models ease the performance analysis of PV systems if the unknown parameters are accurately estimated at various temperatures and unchanged irradiance levels or vice versa. This paper comparatively studies the performances of the two approximate circuit models for the four types of PV modules using the real-coded genetic algorithms. The results indicated that I-V characteristics obtained from the identified parameters exhibit almost similar trend with those given in manufacturers' data sheets under the same conditions. Besides, the estimated parameters obtained from using both models slightly show difference from each other and it can be said that the single diode model is solely satisfactory to model a typical PV model as long as they are accurately estimated.Öğe Katkılı çinko oksit ince filmlerin püskürtülerek kaplama tekniği ile üretilmesi ve polimer güneş hücrelerinde kullanılması(Düzce Üniversitesi, 2023) Gegin, Keziban; Demir, Ahmet; Kösemen, ArifBu çalışmada düşük sıcaklıkta (?150 °C) katkısız, katkılı ve eş katkılı olarak ZnO nanoparçacıklar üretilmesi ve atmosfer koşullarında püskürtülerek kaplama yöntemiyle ters tip organik güneş hücre yapısında elektron taşıma malzemesi olarak kullanılmasının fotovoltaik performans üzerine etkilerinin araştırılması amaçlanmıştır. Bu bağlamda, öncelikle üç farklı element (Al, Sn ve Y) kütlesel olarak sırasıyla %0,5, %1, %3 ve %5 oranlarında katkılanmıştır. Tüm örneklerin yapısal özellikleri taramalı elektron mikroskobu (SEM), enerji dağılımı X-ışını spektroskopisi (EDX), X-ışını kırınımı (XRD) ve X-ışını fotoelektron spektroskopisi (XPS) ile incelenmiştir. Optik özellikler ultraviyole görünür (UV-VIS) spektrofotometre kullanılarak karakterize edilmiştir. Fotovoltaik performans değerlendirmesi için açık devre gerilimi (Voc), kısa devre akım yoğunluğu (Jsc), dolum faktörü (FF) ve güç dönüşüm verimliliği (PCE) gibi temel parametreler değerlendirilmiştir. Özellikle Al katkısı, parçacık boyutunu küçülterek, Jsc değerinde bir artış meydana getirmesiyle hücrelerin fotovoltaik performansının iyileşmesini sağlamıştır. Katkısız ZnO nanoparçacıklı hücreler %1,59 PCE ile referans olarak belirlenmiştir. Tüm durumlar değerlendirildiğinde, tek katkı elementi olarak %5 Al katkılı hücreler %3,72 PCE ile en iyi fotovoltaik performansı göstermiştir. Ayrıca, farklı eş katkı oranları kullanılarak gerçekleştirilen deneylerde, (%0,5 Al - %0,5 Sn), (%0,5 Sn-%1 Y), (%0,5 Al - %1 Y) ve (%0,5 Al - %1 Sn) olacak şekilde dört farklı durum değerlendirilmiştir. Sonuçlar, eş katkılı ZnO nanoparçacıklarının güneş hücrelerinin fotovoltaik performansını artırdığını göstermiştir. En iyi PCE, %2,40 ile (%0,5 Al-%1 Sn) durumunda elde edilmiştir. Bilinen literatürde ilk kez denenen Sn ve Y eş katkısı (%0,5 Al-%1 Y) durumu için, %1,99 PCE ile katkılanmasının güneş hücrelerinin performansını artırabileceğini göstermektedir. Tüm bu sonuçlar, ZnO nanoparçacıklarının ters tip güneş hücrelerinin performansını etkileyen önemli faktörler olduğunu vurgulamaktadır ve uygun katkılama oran ve koşullarını sunmaktadır.Öğe Modeling of a Typical Photovoltaic Module using Matlab/Simulink(Ieee, 2018) Sarma, Nur; Gegin, Keziban; Şimşir, Mehmet; Tutkun, NedimThis paper presents detailed modeling principles of a typical photovoltaic (PV) module using the Matlab/Simulink software. The presented model is based on equations that are obtained from equivalent circuits of the single and double diode models. The presented models are designed with user-friendly blocks from the Simulink block library. The models provide better understanding of the output characteristics of a typical PV module and its changes, since the models can predict the behavior when it operates under various design parameters, as well as environmental conditions. The P-V and I-V output characteristics are determined using the developed models under various temperature and solar irradiation conditions. The accuracy of the developed models is validated by comparing the predicted results with the parameters provided in the datasheet of the investigated PV module.Öğe The novel n-channel liquid crystal organic field effect transistor (LC-n-OFET): A promising technology for low-power electronics(Elsevier, 2024) Kip, Sule Zeynep; Gegin, Keziban; Demir, Ahmet; Koysal, Oguz; Ozturk, Sadullah; Kosemen, ArifIn this study, a novel n-channel liquid crystal organic field effect transistor (LC-n-OFET) was fabricated using a mixture of E7 nematic liquid crystal (NLC) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in an OFET cell. The LC-n-OFET performance was investigated regarding dielectric properties, UV illumination sensitivity, and channel length dependence. Output and transfer current-voltage (I-V) characteristics were measured to evaluate the electrical properties in dark and under UV illumination for varying channel lengths. Additionally, the dielectric characteristics of the LC-n-OFET were determined along with the capacitance-frequency response (Ci-f), threshold voltage (VTh), field-effect mobility (mu FET), and on/off current ratio (Ion/off) as a function of UV illumination intensity and channel length changes. Electrical measurements showed the Ion/off current ratio is inversely proportional to channel length but directly proportional to UV intensity. Meanwhile, the threshold voltage (VTh) and mobility (mu FET) increased with longer channel length and higher light intensity. Overall, the novel LC-n-OFET exhibited promising performance with low VTh, high mu FET, and large Ion/off.
