Browsing by Author "Bilgin,N."

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Effect of Porosity on the Efficiency of Dssc Produced by Using Nano-Size Tio2 Powders
(2014) Bilgin,N.; Park,J.; Ozturk,A.; Metallurgical and Materials Engineering; English Translation and Interpretation; 02. School of Arts and Sciences; 06. School Of Engineering; 01. Atılım University
The effect of porosity on the energy conversion efficiency of dye-sensitized solar cells (DSSCs) prepared by using pastes formed by mixing 20 nm and 200 nm TiO2 particles in different ratios is investigated. XRD and SEM analysis have been done to investigate the microstructure of pastes. The energy conversion efficiency of DSSCs was determined by drawing complete current density-voltage curve. The DSSC prepared using the mixture composed of 40 wt% 20 nm and 60 wt% 200 nm TiO2 particles maintained best energy conversion efficiency of 6.74%. The energy conversion efficiency of the DSSCs prepared by using pastes based on the mixture of two different size of TiO 2 particles is much better than that of the DSSCs prepared by using pastes composed of either only 20 nm or only 200 nm of TiO2 particles. The improved energy conversion efficiency is attributed to the establishment of further porous structure that lets more dye absorption from the surface through interior which provides enhancement of light absorption and multiple scattering.
Influence of Particle Size of Tio2 Powder on the Energy Conversion Efficiency of a Dye-Sensitized Solar Cell
(2013) Bilgin,N.; Park,J.; Ozturk,A.; Metallurgical and Materials Engineering; English Translation and Interpretation; 02. School of Arts and Sciences; 06. School Of Engineering; 01. Atılım University
Dye-sensitized solar cells (DSSCs) have been fabricated using a TiO2 paste composed of mixtures of 25 nm and 250 nm TiO2 particles at various ratios. A maximum energy conversion efficiency of 6.7% has been achieved using the DSSC, based on a TiO2 layer composed of 40 wt% 25 nm and 60 wt% 250 nm TiO2 particles. The short-circuit current density, open-circuit voltage, and filling factor of the cell were 12.95 mA, 0.82 V, and 0.63, respectively. The overall performance of the DSSCs based on TiO2 layers composed using a mixture of two different sized particles is much better than that of either only 25 nm or only 250 nm TiO2 particles. It is recognized that adding the larger particles to the small particles in the TiO2 paste increases the dye absorption and light scattering effects of DSSC, resulting in a higher short-circuit current density and improved energy conversion efficiency. © (2013) Trans Tech Publications, Switzerland.
Citation - Scopus: 2
Synthesis of Tio2 Nanostructures Via Hydrothermal Method
(American Ceramic Society, 2015) Bilgin,N.; Agartan,L.; Park,J.; Ozturk,A.; Metallurgical and Materials Engineering; English Translation and Interpretation; 02. School of Arts and Sciences; 06. School Of Engineering; 01. Atılım University
Titania (TiO2) nanostructures were produced via hydrothermal method using amorphous TiO2 powders synthesized by the sol-gel precipitation process. The hydrothermal system was isolated from the environment and hydrothermal reactions were allowed to execute at 130 °C for 36 h at autogeneous pressure, and at a stirring rate of 250 rpm. Scanning electron microscopy (SEM) analysis revealed that TiO2 nanofibers formed instead of nanotubes upon utilization of amorphous TiO2 precursor. After hydrothermal synthesis, the powders were acid treated by HCl several times. X-ray diffraction (XRD) analysis identified that the synthesized powders were Na-titanate and remained Na-titanate even after subjecting to acidic treatments several times. The photocatalytic performance of the powders was evaluated by degradation of methylene blue (MB) solution in UV illumination. Results were compared with nanotubes which were synthesized previously using P25 commercial titania powder and have shown that TiO2 in tubular structure offers better photocatalytic performance for the degradation of MB solution under UV illumination as compared to fiber-like structure. Copyright © 2015 by The American Ceramic Society. All rights reserved.