Showing papers by "Muhammad Hassan Sayyad published in 2018"

Synthesis, computational study and characterization of a 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2- one azo dye for dye-sensitized solar cell applications

Abstract: A solution-processable 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2-one azo dye was synthesized. Analysis of measured UV-visible absorption spectrum and frontier orbitals computed using simplified time dependent density functional theory (sTDDFT) revealed its suitability for optoelectronic applications. A dye-sensitized solar cell (DSSC) was fabricated using this metal-free organic dye as a sensitizer. The photovoltaic parameters of the cell were studied under simulated AM 1.5 illumination (100 mWcm $$^{-2}$$ ). Comparing the photovoltaic data with a DSSC using a different member of the azo family of dyes, open circuit voltage and fill factor of the device studied in this work were found higher by 33 and 104%, respectively. The performance was also compared with the DSSCs fabricated using 49 commercial mordant dyes and open circuit photovoltage of the device studied in this work was found higher. To gain insight into its charge transport, impedance spectroscopy was performed. Impedance spectra were observed both voltage and frequency dependent.

Step-by-Step Heating of Dye Solution for Efficient Solar Energy Harvesting in Dye-Sensitized Solar Cells

Abstract: A step-by-step heat treatment was applied to ruthenium-based N719 dye solution for its potential application in dye-sensitized solar cells (DSSCs). The effects were analyzed and compared with standard untreated devices. A significant increase in short circuit current density was observed by employing a step-by-step heating method for dye solution in DSSCs. This increase of Jsc is attributed to the enhancement in dye adsorption by the surface of the semiconductor and the higher number of charge carriers generated. DSSCs fabricated by a heated dye solution have achieved an overall power conversion efficiency of 8.41% which is significantly higher than the efficiency of 7.31% achieved with DSSCs fabricated without heated dye. Electrochemical impedance spectroscopy and capacitance voltage studies were performed to understand the better performance of the device fabricated with heated dye. Furthermore, transient photocurrent and transient photovoltage measurements were also performed to gain an insight into interfacial charge carrier recombinations.

Efficiency Enhancement in Plasmonic Dye-Sensitized Solar Cell Employing High Performance TiO2 Photoanode Doped with Silver Nanoparticles

Abstract: High performance TiO2 photoanodes undoped and doped with silver nanoparticels of size about 15 nm were fabricated. Employing these electrodes dye-sensitized solar cells (DSSCs) were fabricated using N719 dye as sensitizer and iodide-triodide as redox couple. Current-voltage measurements were performed under the illumination of 100 mW cm-2 (AM 1.5). The electrical parameters of the fabricated cells were extracted from the current-voltage data that include open-circuit voltage, short-circuit current, shunt resistance, series resistance, fill-factor, ideality factor and solar energy-to-electricity conversion efficiency. The comparison of parameters revealed improvement in both the photovoltaic and electrical parameters of the plasmonic cell. The conversion efficiency measured for the reference cell without Ag NPs in TiO2 was 7.43 %, whereas the efficiency of plasmonic device with TiO2:Ag NPs was 9.26 %, resulting an overall efficiency improvement of 23% with Ag NPs. The increased performance of the plasmonic DSSC can be assigned to the improvement of its photovoltaic and electrical parameters. The improved short-circuit photocurrent density appears to be boosted due the enhanced light harvesting capability of the photoanode caused by the localized surface plasmon resonance effect induced in Ag nanoparticles. While, the rise in Voc can be credited to the upward shift of Fermi level of TiO2 due to the dopping of Ag nanoparticles in TiO2 network.

Enhanced performance in dye-sensitized solar cell via laser generated noble metal nanoparticles treatment of photoelectrode

Abstract: To improve the conversion efficiency of dye-sensitized solar cell, the cell was fabricated employing silver nanoparticles doped photoanode. The nanoparticles of silver were produced using the pulsed laser ablation technique. The I-V characteristics and impedance spectroscopic measurements were performed on the doped and undoped photoanode based devices under simulated AM 1.5 illumination (100 mWcm−2 ) and dark, respectively. The nanoparticles doped photoanode based plasmonic DSSC exhibited about 46.3 % higher efficiency than the reference cell. This boosted performance of the plasmonic DSSC can be attributed to enhanced interfacial charge transfer, decrease of charge recombination, d…