Master of Science
Dr. Zhifeng Ding
In this thesis Cu2ZnSnS4 nanocrystal synthesis was optimized by way of photoelectrochemical measurements through tuning the stoichiometry. Formation of a Cu2ZnSnS4 light-absorbing layer was studied using multiple depositions methods. These included dropcasting, electrophoretic deposition, and use of 3-mercaptopropyl trimethoxysilane as a chemical linker. Dropcasting samples were compared according to the solvents used to suspend the nanocrystals. Photoelectrochemical measurements were used to compare dropcasting with electrophoretic deposition and use of 3-mercaptopropyl trimethoxysilane as a chemical linker. Dropcasting was shown to be the least effective method of depositing the light-absorbing layer. Samples prepared by electrophoretic deposition were optimized according to a number of variables, which included deposition time, nanocrystal concentration, solvent and applied potential. A concentration of 2 g/L, in isopropanol with an applied potential of 50 V for 40 seconds gave the largest photocurrent of all films tested (106 μA/cm2). Using 3-mercaptopropyl trimethoxysilane as a chemical linker photocurrent results as high as 74 μA/cm2 was observed from a much thinner layer. Preliminary solar cells were fabricated using electrophoretic deposition, one of the cells fabricated had a fill factor of 0.27. In this thesis electrophoretic deposition was proven to be the best method of depositing Cu2ZnSnS4 nanocrystals. While a functioning solar cell was fabricated, preliminary cells showed room for much improvement. This shows that upon further optimization, an efficient solar cell can be realized.
Jeffs, Kyle S.B., "Optimization of p-Type CZTS Nanocrystal Thin Film Layers For Applications in Low Cost Photovoltaic Devices" (2014). Electronic Thesis and Dissertation Repository. 2292.