Browsing by Author "Kaya, F. S."

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Comparative Evaluation of Al/Chlorophyll Device Under Varying Irradiance Intensity: Machine Learning Modeling Vs. Experimental Data
(Elsevier Science Sa, 2025) Kaya, F. S.; Orak, I.; Balci, Z.; Kilic, Z.
This study investigated the effect of chlorophyll, a natural photosynthetic pigment, on solar cell characteristic parameters. Chlorophyll thin film layers were analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The current-voltage (I-V) characteristics of an Al/p-Si/chlorophyll/Al structure were investigated to understand the device's behavior under different light intensities. The fill factor (FF) and efficiency values (eta), which are the characteristic parameters of the solar cell, were calculated from the current values predicted by machine learning (ML) models using the voltage values of the Al/p-Si/chlorophyll/Al devices produced and the results obtained were compared. The results demonstrate the light intensity-dependent electrical response of the Al/p-Si/chlorophyll/Al structure and provide valuable insights for further developments in organic photodetectors and solar cell technology.
Determination of Temperature and Light Intensity on the Ni/Chlorophyll-a N-Gap Device
(Pergamon-elsevier Science Ltd, 2023) Kaya, F. S.
Based on the light absorption property of chlorophylls, chlorophyll-a molecules, the most abundant molecules of chlorophylls, were coated on the interfacial layer for a fabricated Ni/chlorophyll-a/n-GaP device. Cur-rent-voltage (I-V) measurements were assessed for different temperatures and levels of light intensity. The characteristic parameters of the device were calculated using different methods based on I-V measurements taken at room temperature. The Ni/chlorophyll-a/n-GaP device was subjected to I-V analysis for a temperature range of 80-300 K. The barrier height values increased with increasing temperature whereas ideality factor values decreased. The I-V characteristics of the device were examined under various light intensities at 300 K and the photovoltaic effects of the device were analyzed. The photocurrent value increased from 2.58 x 10-7 at 30 mW cm-2 to 5.46 x 10-7 at 100 mW cm-2, and the sensitivity value increased from 9.72 at 30 mW cm-2 to 18.83 at mW & sdot;cm- 2, almost doubling. The results indicate that a chlorophyll-a layer has potential as a novel material for optoelectronic applications.
A Study on Investigation of Electrical Properties of Au/Chlorophyll-a Structure
(Elsevier, 2023) Kaya, F. S.; Duman, S.; Turgut, G.
The chlorophyll-a (Chl-a) thin film has been formed on the n-Si substrate using a spin-coater. The electrical properties of the Au/Chl-a/n-Si/Al structure have been examined with the data obtained from the current-voltage (I-V) measurements in the dark and under illumination at room temperature. The ideality factor (n) and barrier height (phi b) values have been calculated as 1.24 and 0.799 eV in the dark and 1.08 and 0.824 eV in daylight at room temperature. Also, I-V measurements were taken under different illuminations, and some photoelectrical parameters of the Au/Chl-a/n-Si/Al structure, such as photocurrent, photosensitivity, and Ion/Ioff, were investigated. The results show that the Chl-a thin film can be utilized to fabricate photodiodes and solar cells.