Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science
Nicohl I. Cintron Rodriguez - Universidad Metropolitana Recinto de Cupey
Co-Author(s): Mitk'El B. Santiago Berrios; Universidad Metropolitana Recinto de Cupey, San Juan PR ; Maria Cepeda; Universidad Metropolitana Recinto de Cupey, San Juan PR
Zinc Oxide (ZnO) materials have captivated the attention of researchers for their simple and low-cost synthesis while they prove to be useful in a wide range of purposes encompassing areas from medicine to energy harvesting applications. This semiconductor has a wide band gap of 3.37 eV, making it an ideal semiconductor for the construction of various kinds of devices such as solar cells. Dye-sensitized solar cells (DSSC’s) have attracted attention of researchers for their ease and low-cost construction. A DSSC’s consists of a FTO contact where the photoanode is deposited, a dye such as Ruthenizer (N719 dye), an iodolyte solution, and a back contact to complete the device. In DSSC’s ZnO has been suggested to become a substitute of a most commonly used titanium oxide (TiO2). This is due to the environmentally friendly characteristics, higher electron mobility and wider band gap (3.37 eV) compared to TiO2. Recently, our research group demonstrated that the inclusion of ligands at the ZnO crystal defects have noticeable effects its electronic properties, possibly enhancing them. In this study, we examined the photoelectrochemical properties of pure ZnO and ZnO functionalized with Benzoic Acid (BA) and 3-Mercaptopropionic Acid (3-MPA) in a DSSC environment. We ZnO and functionalized ZnO materials were prepared using hydrothermal synthesis. The characterization of these materials have been previously reported by our laboratory and was done using X-ray powder diffraction, UV-vis spectroscopy, and FT-IR spectroscopy with the ATR module. The X-ray powder diffraction showed the characteristics diffraction peaks of ZnO in the wurtzite structure. The UV-vis spectroscopy demonstrated that the band gap of these materials is affected due to the presence of the ligand. FT-IR spectroscopy confirms that the ligand was attached at the ZnO surface at the defects of the crystal. Also, ZnO was functionalized with BA and 3-MPA and these materials were characterized doing photoelectrochemistry using a DSSC’s configuration. The results demonstrated that DSSC’s using 3-MPA increasing the absorption of the photoanode at a higher wavelength. The DSSC prepared with ZnO with benzoic acid demonstrated a higher absorption in comparison with pure ZnO. These results suggest that 3-MPA is acting as a protecting agent of the ZnO surface and that there is a chemical reaction between the thiol group and the carboxylate end of the N719 dye forming a molecular wire at the ZnO surface. Further experiment will be required to determine if this hypothesis is true. We have observed during the construction of DSSC’s the ZnO film stripped from the FTO surface in several occasions once the dye was applied due to their acidic environment. For future experiments, we are going to test this material using alkaline conditions. This poster presentation will address the synthesis of ZnO materials, the construction of DSSCs and the photoelectrochemical characterization of these devices.
Funder Acknowledgement(s): This work was supported by the National Science Foundation NSF-PREM: Center for Interfacial Electrochemistry of Energy Materials (Grant No.1827622)
Faculty Advisor: Mitk'El B. Santiago Berrios, email@example.com
Role: My tasks for this consisted in synthesizing ZnO nanoparticles through hydrothermal titration and characterizing them using X-ray powder diffraction, UV-vis spectroscopy, and FT-IR spectroscopy with the ATR module. Also, I functionalized ZnO thin films with organic materials such as benzoic acid (BA) and 3-Mercaptopropionic acid (3-MPA) to then characterize them photoelectrochemically using a DSSC?s configuration. This opportunity gave me the chance to confirm chemistry is my passion by raising up new curiosities in a topic I wasn?t focused on while I put to test my skills on a research lab.