Date of Publication

9-9-2011

Document Type

Master's Thesis

Degree Name

Master of Science in Physics

Subject Categories

Physics

College

College of Science

Department/Unit

Physics

Thesis Adviser

Gil Nonato C. Santos

Defense Panel Chair

Lydia S. Roleda

Defense Panel Member

Emmanuel T. Rodulfo
Ivan B. Culaba

Abstract/Summary

Dye Sensitized Solar Cells (DSSCs) with photoelectrodes synthesized via Horizontal Vapor Phase Crystal (HVPC) Growth Technique were fabricated and characterized in the present study. Nanostructured TiO2 was first synthesized on glass substrates at growth temperatures of 1000 oC, 1100 oC, and 1200 oC with varying substrate distance from the bulk powder to determine the optimum substrate location in the fabrication of the photoelectrodes for DSSCs. Other parameters such as the amount of TiO2 powder (99.99% P25 Degussa), dwell time, and ramp rate were kept constant at 35 mg, 6 h, and 10 oC/min respectively. The synthesized TiO2 nanomaterials were then subjected to Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) analysis. SEM and EDX results revealed that monodispersed TiO2 nanoparticles, nanocubes, nanoprisms, nanorods, and nanowires were successfully grown on glass substrate particularly at a substrate distance of 80 mm from the bulk powder. In the fabrication of DSSCs, Flourine-doped Tin Oxide (FTO) was used to deposit nanostructured TiO2 for their photoelectrodes employing the optimum substrate distance identified by SEM analysis. Bixin dye extracted from Annatto was utilized as a low-cost sensitizer and a graphite coated FTO as counter-electrode. Three DSSCs with photoelectrodes fabricated at different growth temperatures were subjected to artificial light vi De La Salle University and actual sunlight characterization to assess their photovoltaic performance in terms of the open-circuit voltage (Voc) and short-circuit photocurrent (Isc). All the DSSCs with photoelectrode fabricated by HVPC growth technique achieved a relatively large open-circuit voltage (Voc) of 387 mV, 427 mV, and 412 mV for growth temperature of 1000 oC, 1100 oC, and 1200 oC respectively. Among the fabricated DSSCs with photoelectrodes grown at different temperatures, DSSC-1200 exhibited the largest short-circuit photocurrent (Isc) of 45 µA compared to 40 µA for DSSC-1000 and 39 µA for DSSC-1100. As a consequence, DSSC-1200 demonstrated the largest recorded fill-factor of 0.24 and efficiency of 0.12 %. When the photoelectrode of a DSSC fabricated by solution based technique was first subjected to HVPC growth technique, a very large enhancement in open-circuit voltage (Voc) was achieved. The DL-DSSC-1200 resulted to the following cell parameters; Isc = 290 µA, Voc = 488 mV, Imp = 119 µA, Vmp = 269 mV, FF = 0.23, and = 0.87 % making it the best performing DSSC in the present study. In conclusion, HVPC growth technique could potentially be incorporated in the fabrication of photoelectrode for DSSCs either by itself or in conjunction with the solution based technique. Independently, it can be used to grow nanostructured TiO2 on FTO to serve as photoelectrode but an efficient sensitizer should be used in order to enhance its light absorption ability. When used in conjunction with solution based technique, a low-cost sensitizer like Bixin extract from Annatto used in the present study will be sufficient to demonstrate an enhancement in DSSC performance as a result of the relatively high open-circuit voltage (Voc) when the photoelectrode has undergone HVPC growth technique.

Abstract Format

html

Language

English

Format

Electronic

Electronic File Format

MS WORD

Accession Number

CDTG005075

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

86 leaves : ill. ; 1 computer optical disc

Keywords

Dye-sensitized solar cells; Renewable energy sources

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