Studies on zinc oxide nanorod dye sensitized solar cell | |
| Author | Bora, Tanujjal |
| Call Number | AIT Thesis no.ME-09-01 |
| Subject(s) | Zinc oxide Dye-sensitized solar cells |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Microelectronics, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ME-09-01 |
| Abstract | Dye sensitized solar cell (DSSC), also known as Grätzel’s cell, is one of the most extensively studied solar cells in the present time because of its potentiality for high efficiency and low manufacturing cost. Using Zinc Oxide (ZnO) nanorods as photoelectrode material, DSSC performance with different surface area have been studied with various length, diameter and density of ZnO nanorods to optimize the hydrothermal growth conditions (precursor solution concentration and growth time) of the ZnO nanorods for maximum efficient DSSC. In order to increase the surface area of the photoelectrode for better dye adsorption, a branched like structure of the ZnO nanorods was obtained by hydrothermally growing vertical ZnO nanorods on FTO (F:SnO2) glass substrate from aqueous medium followed by a secondary stage hydrothermal growth of the ZnO nanorods in lateral direction from the surface of the existing vertical ZnO nanorods. The optimum hydrothermal growth conditions of the branched like ZnO nanorods for the maximum efficient DSSC (VOC = 0.54 V, JSC = 2.25 mA/cm2, FF = 41.16%, η = 0.5%, active area = 1 cm2) was obtained by using a 20 mM precursor solution concentration with 40 hours of growth time for both primary stage (vertical nanorods) and secondary stage (lateral nanorods) growth of the ZnO nanorods respectively. The length, diameter and density of the vertical and lateral ZnO nanorods obtained using the optimum conditions for the hydrothermal growth are 8.5 μm, 400 nm, 3.68x108/cm2 and 2.75 μm, 200 nm, 41.67x108/cm2 respectively. A maximum efficiency of 5.34% (VOC = 0.67 V, JSC = 11 mA/cm2, FF = 72.40%) was successfully obtained in this case for a 0.09 cm2 active area DSSC by using the optimum hydrothermal growth conditions determined for the ZnO nanorods. In another part of the thesis, the sensitization time for maximum dye adsorption on the ZnO nanorods was studied and an optimum time of 24 hours for maximum dye adsorption was determined. To decrease the sensitization time for maximum dye adsorption and obtain a uniform layer of dye molecules, another approach of dye sensitization using thiol molecules have also been studied. Further improvement in the DSSC performance was observed by using gold (Au) nanoparticles in the photoelectrode. By synthesizing Au nanoparticles on the surface of the ZnO nanorods, the efficiency of 1 cm2 DSSC was increased from 0.5% to 1.02%. Under this condition, due to the reduction in electron recombinations and capacitive effect in the DSSC, improvement in the JSC (from 2.14 mA/cm2 to 3.80 mA/cm2) and VOC (from 0.54 V to 0.69V) were observed respectively. In another experiment, silver grid lines were made on the counter electrode by ink jet printing technique and improvement in the fill factor (from 39.82% to 45.06%) of the DSSC was observed. |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ME-09-01 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Microelectronics (ME) |
| Chairperson(s) | Dutta, Joydeep |
| Examination Committee(s) | Afzulpurkar, Nitin V.;Weerakorn Ongsakul |
| Scholarship Donor(s) | Asian Institute of Technololgy Fellowship |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2009 |