Please use this identifier to cite or link to this item: http://localhost:8080/xmlui/handle/123456789/46
Title: Theoretical and Experimental Studies of Titanium Dioxide Based Dye-Synthesized Solar Cells
Authors: Tripathi, Brijesh
Keywords: Solar Energy
Issue Date: Aug-2013
Publisher: Pandit Deendayal Energy University, Gandhinagar
Series/Report no.: 10SSEPH01;ET000019
Abstract: Modeling and simulation is done to explore the effect of various parameters on the electrical performance of TiO2 nanoparticle/nanorod based dye-sensitized solar cells. The model could be validated by simulation software TiberCAD and the experimental results available in the literature. The results show that the porosity decreases with increasing diameter of nanorod for a fixed value of inter-rod separation. The short-circuit current density can be improved by optimizing the nanorod diameter. From this study it is observed that the nanorods of diameter from 65 nm to 90 nm with porosity range from 0.43 to 0.66 would result in better performing DSSC. Further, The steady-state current–voltage curve and dynamic response of a DSSC is mathematically modeled based on the electrical equivalent circuit. The effect of temperature and illumination on the steady state and dynamic parameters of dyesensitized solar cells are studied. It is found that the dynamic resistance of DSSC decreases from 619.21 to 90.34 with an increase in illumination level from 200 W/m 2 to 800 W/m2 . A positive temperature coefficient of dynamic resistance is observed. The interfacial charge transfer and recombination losses at the oxide/dye/electrolyte interface are found to be the most influential factor in the overall conversion efficiency and included in the mathematical model. The saturation current of rectifying diode and saturation current of recombination diode are responsible for the transfer recombination losses and have major influence on the overall conversion efficiency. Preparation and characterization of the nano-crystalline TiO2 based working electrodes was done. The working electrode consists of a layer of porous TiO2 material on FTO coated glass substrates. Various TiO2 layer deposition methods, such as spray-pyrolysis, hydrothermal method, and doctor-blade method have been tried out. The scanning electron microscopy (SEM) is done for morphological characterization of these layers. X-ray diffraction technique is used to explore the phases of TiO2 in the layer. Surface profilometer is used to explore exact thickness and roughness of the layer. Further, these electrodes have been used as a working electrode of DSSC and the current-voltage characterization is done to explore their actual device performance. The TiO2 layers developed by doctor-blade method have performed better than others. The fabrication of dye-sensitized solar cells with Ruthenium-based sensitizer dye as absorbers is described and the effect of electrode morphology on solar cell performance is presented. A dye-sensitized solar cell is fabricated with 12 m thick TiO2 layer, produced power conversion efficiency of 2.9% under AM1.5 spectrum with photo-generated current density of 7.2 mA/cm2 and open-circuit voltage of 672 mV. An entire electrochemical phenomenon of TiO2-electrolyte interface, diffusion of electrolyte and charge transfer at counter electrode is mathematically modeled using electrical equivalent circuit. The effect of temperature and illumination on the steady state and dynamic parameters of dye-sensitized solar cells is also studied. An improvement in the photoelectric conversion efficiency of a dye-sensitized solar cell is reported by simulating DSSC with plasmon enhanced light trapping in the absorbing region observed experimentally. Improved light transmission is observed experimentally in silver nanoparticle coated FTO glass. The size of Ag nanoparticle is estimated as 110 nm by comparing theoretical results with experimental data. The transmission data is used to explore the effect on electrical parameters of dye-sensitized solar cell using theoretical model. Localized surface plasmon resonance incurred by Ag nanoparticles is also used to enhance the photoelectric conversion efficiency of a TiO2 nanorod based dye-sensitized solar cell (DSSC). The transmission data is used to explore the effect on electrical parameters of TiO2 nanorod based DSSC using theoretical model. Current density increased from 11.7 mA/cm2 to 12.34 mA/cm2 and open-circuit voltage increased from 704 mV to 709.5 mV. Overall relative efficiency enhancement of 6.67% is showed in TiO2 nanorod based DSSC due to plasmon induced light trapping. For a TiO2 nanoparticle-based DSSC, relative efficiency enhancement of more than 8% has been demonstrated. Plasmon enhanced TiO2 nanoparticle-based DSSC showed increased efficiency of 11.76% under AM1.5 solar spectrum compared with 10.86% for a DSSC without Ag nanoparticles. In this case, the current density increased from 16.64 mA/cm2 to 17.55 mA/cm2 and the open-circuit voltage increased from 853 mV to 857 mV.
Description: Under the guidance of Dr. Manoj Kumar and Dr. Abhijit Ray
URI: http://localhost:8080/xmlui/handle/123456789/46
Appears in Collections:Department of Solar Energy

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